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Glidden CK, Singleton AL, Chamberlin A, Tuan R, Palasio RGS, Caldeira RL, Monteiro AMV, Lwiza KMM, Liu P, Silva V, Athni TS, Sokolow SH, Mordecai EA, De Leo GA. Climate and urbanization drive changes in the habitat suitability of Schistosoma mansoni competent snails in Brazil. bioRxiv 2024:2024.01.03.574120. [PMID: 38260310 PMCID: PMC10802398 DOI: 10.1101/2024.01.03.574120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Schistosomiasis is a neglected tropical disease caused by Schistosoma parasites. Schistosoma are obligate parasites of freshwater Biomphalaria snails, so controlling snail populations is critical to reducing transmission risk. As snails are sensitive to environmental conditions, we expect their distribution is significantly impacted by global change. Here, we leveraged machine learning, remote sensing, and 30 years of snail occurrence records to map the historical and current distribution of competent Biomphalaria throughout Brazil. We identified key features influencing the distribution of suitable habitat and determined how Biomphalaria habitat has changed with climate and urbanization over the last three decades. Our models show that climate change has driven broad shifts in snail host range, whereas expansion of urban and peri-urban areas has driven localized increases in habitat suitability. Elucidating change in Biomphalaria distribution - while accounting for non-linearities that are difficult to detect from local case studies - can help inform schistosomiasis control strategies.
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2
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Rohr JR, Sack A, Bakhoum S, Barrett CB, Lopez-Carr D, Chamberlin AJ, Civitello DJ, Diatta C, Doruska MJ, De Leo GA, Haggerty CJE, Jones IJ, Jouanard N, Lund AJ, Ly AT, Ndione RA, Remais JV, Riveau G, Schacht AM, Seck M, Senghor S, Sokolow SH, Wolfe C. A planetary health innovation for disease, food and water challenges in Africa. Nature 2023:10.1038/s41586-023-06313-z. [PMID: 37438520 DOI: 10.1038/s41586-023-06313-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 06/12/2023] [Indexed: 07/14/2023]
Abstract
Many communities in low- and middle-income countries globally lack sustainable, cost-effective and mutually beneficial solutions for infectious disease, food, water and poverty challenges, despite their inherent interdependence1-7. Here we provide support for the hypothesis that agricultural development and fertilizer use in West Africa increase the burden of the parasitic disease schistosomiasis by fuelling the growth of submerged aquatic vegetation that chokes out water access points and serves as habitat for freshwater snails that transmit Schistosoma parasites to more than 200 million people globally8-10. In a cluster randomized controlled trial (ClinicalTrials.gov: NCT03187366) in which we removed invasive submerged vegetation from water points at 8 of 16 villages (that is, clusters), control sites had 1.46 times higher intestinal Schistosoma infection rates in schoolchildren and lower open water access than removal sites. Vegetation removal did not have any detectable long-term adverse effects on local water quality or freshwater biodiversity. In feeding trials, the removed vegetation was as effective as traditional livestock feed but 41 to 179 times cheaper and converting the vegetation to compost provided private crop production and total (public health plus crop production benefits) benefit-to-cost ratios as high as 4.0 and 8.8, respectively. Thus, the approach yielded an economic incentive-with important public health co-benefits-to maintain cleared waterways and return nutrients captured in aquatic plants back to agriculture with promise of breaking poverty-disease traps. To facilitate targeting and scaling of the intervention, we lay the foundation for using remote sensing technology to detect snail habitats. By offering a rare, profitable, win-win approach to addressing food and water access, poverty alleviation, infectious disease control and environmental sustainability, we hope to inspire the interdisciplinary search for planetary health solutions11 to the many and formidable, co-dependent global grand challenges of the twenty-first century.
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Affiliation(s)
- Jason R Rohr
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA.
| | - Alexandra Sack
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Sidy Bakhoum
- Department of Animal Biology, Université Cheikh Anta Diop, Dakar, Senegal
| | - Christopher B Barrett
- Charles H. Dyson School of Applied Economics and Management, Cornell University, Ithaca, NY, USA
| | - David Lopez-Carr
- Department of Geography, University of California, Santa Barbara, CA, USA
| | - Andrew J Chamberlin
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | | | - Cledor Diatta
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Molly J Doruska
- Charles H. Dyson School of Applied Economics and Management, Cornell University, Ithaca, NY, USA
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - Christopher J E Haggerty
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | - Nicolas Jouanard
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
- Station d'Innovation Aquacole, Saint-Louis, Senegal
| | - Andrea J Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, CA, USA
- Department of Environmental and Occupational Health, University of Colorado School of Public Health, Anschutz Medical Campus, Aurora, CO, USA
| | - Amadou T Ly
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Raphael A Ndione
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Justin V Remais
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA
| | - Gilles Riveau
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
- Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunité of Lille, Lille, France
| | - Anne-Marie Schacht
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Momy Seck
- Station d'Innovation Aquacole, Saint-Louis, Senegal
| | - Simon Senghor
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Susanne H Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | - Caitlin Wolfe
- College of Public Health, University of South Florida, Tampa, FL, USA
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3
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Igoe M, Casagrandi R, Gatto M, Hoover CM, Mari L, Ngonghala CN, Remais JV, Sanchirico JN, Sokolow SH, Lenhart S, de Leo G. Reframing Optimal Control Problems for Infectious Disease Management in Low-Income Countries. Bull Math Biol 2023; 85:31. [PMID: 36907932 PMCID: PMC10008208 DOI: 10.1007/s11538-023-01137-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 02/20/2023] [Indexed: 03/14/2023]
Abstract
Optimal control theory can be a useful tool to identify the best strategies for the management of infectious diseases. In most of the applications to disease control with ordinary differential equations, the objective functional to be optimized is formulated in monetary terms as the sum of intervention costs and the cost associated with the burden of disease. We present alternate formulations that express epidemiological outcomes via health metrics and reframe the problem to include features such as budget constraints and epidemiological targets. These alternate formulations are illustrated with a compartmental cholera model. The alternate formulations permit us to better explore the sensitivity of the optimal control solutions to changes in available budget or the desired epidemiological target. We also discuss some limitations of comprehensive cost assessment in epidemiology.
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Affiliation(s)
- Morganne Igoe
- Department of Mathematics, University of Tennessee, Knoxville, TN, USA.
| | - Renato Casagrandi
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
| | - Marino Gatto
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
| | - Christopher M Hoover
- Division of Environmental Health Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Lorenzo Mari
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
| | | | - Justin V Remais
- Division of Environmental Health Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - James N Sanchirico
- Environmental Science and Policy, University of California, Davis, Davis, CA, USA
| | - Susanne H Sokolow
- Stanford Program for Diseases Ecology, Health and the Environment, Stanford University, Pacific Grove, CA, USA
| | - Suzanne Lenhart
- Department of Mathematics, University of Tennessee, Knoxville, TN, USA
| | - Giulio de Leo
- Department of Earth System Science and Department of Oceans, Hopkins Marine Station, Stanford Doerr School of Sustainability, Stanford University, Pacific Grove, CA, USA
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4
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Haggerty CJE, Delius BK, Jouanard N, Ndao PD, De Leo GA, Lund AJ, Lopez-Carr D, Remais JV, Riveau G, Sokolow SH, Rohr JR. Pyrethroid insecticides pose greater risk than organophosphate insecticides to biocontrol agents for human schistosomiasis. Environ Pollut 2023; 319:120952. [PMID: 36586553 DOI: 10.1016/j.envpol.2022.120952] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
Use of agrochemicals, including insecticides, is vital to food production and predicted to increase 2-5 fold by 2050. Previous studies have shown a positive association between agriculture and the human infectious disease schistosomiasis, which is problematic as this parasitic disease infects approximately 250 million people worldwide. Certain insecticides might runoff fields and be highly toxic to invertebrates, such as prawns in the genus Macrobrachium, that are biocontrol agents for snails that transmit the parasites causing schistosomiasis. We used a laboratory dose-response experiment and an observational field study to determine the relative toxicities of three pyrethroid (esfenvalerate, λ-cyhalothrin, and permethrin) and three organophosphate (chlorpyrifos, malathion, and terbufos) insecticides to Macrobrachium prawns. In the lab, pyrethroids were consistently several orders of magnitude more toxic than organophosphate insecticides, and more likely to runoff fields at lethal levels according to modeling data. At 31 water contact sites in the lower basin of the Senegal River where schistosomiasis is endemic, we found that Macrobrachium prawn survival was associated with pyrethroid but not organophosphate application rates to nearby crop fields after controlling for abiotic and prawn-level factors. Our laboratory and field results suggest that widely used pyrethroid insecticides can have strong non-target effects on Macrobrachium prawns that are biocontrol agents where 400 million people are at risk of human schistosomiasis. Understanding the ecotoxicology of high-risk insecticides may help improve human health in schistosomiasis-endemic regions undergoing agricultural expansion.
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Affiliation(s)
- Christopher J E Haggerty
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Bryan K Delius
- Duquesne University, Department of Biological Sciences, Pittsburgh, PA, USA
| | - Nicolas Jouanard
- Centre de Recherche Biomédicale Espoir pour La Santé, Saint-Louis, Senegal; Station D'Innovation Aquacole, Saint-Louis, Senegal
| | - Pape D Ndao
- Station D'Innovation Aquacole, Saint-Louis, Senegal; Université Gaston Berger (UGB), Route de Ngallèle, BP 234, Saint-Louis, Senegal
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - Andrea J Lund
- Department of Environmental and Occupational Health, Colorado School of Public Health, University of Colorado, Anschutz, Aurora, CO, USA
| | - David Lopez-Carr
- Human-Environment Dynamics Lab, Department of Environmental Studies, UCSB, Santa Barbara, CA, USA
| | - Justin V Remais
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA
| | - Gilles Riveau
- Centre de Recherche Biomédicale Espoir pour La Santé, Saint-Louis, Senegal; University of Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL, Center for Infection and Immunity of Lille, Lille, France
| | - Susanne H Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | - Jason R Rohr
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA; Marine Science Institute, University of California, Santa Barbara, CA, USA.
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5
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Pourtois JD, Tallam K, Jones I, Hyde E, Chamberlin AJ, Evans MV, Ihantamalala FA, Cordier LF, Razafinjato BR, Rakotonanahary RJL, Tsirinomen'ny Aina A, Soloniaina P, Raholiarimanana SH, Razafinjato C, Bonds MH, De Leo GA, Sokolow SH, Garchitorena A. Climatic, land-use and socio-economic factors can predict malaria dynamics at fine spatial scales relevant to local health actors: Evidence from rural Madagascar. PLOS Glob Public Health 2023; 3:e0001607. [PMID: 36963091 PMCID: PMC10021226 DOI: 10.1371/journal.pgph.0001607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 01/23/2023] [Indexed: 02/24/2023]
Abstract
While much progress has been achieved over the last decades, malaria surveillance and control remain a challenge in countries with limited health care access and resources. High-resolution predictions of malaria incidence using routine surveillance data could represent a powerful tool to health practitioners by targeting malaria control activities where and when they are most needed. Here, we investigate the predictors of spatio-temporal malaria dynamics in rural Madagascar, estimated from facility-based passive surveillance data. Specifically, this study integrates climate, land-use, and representative household survey data to explain and predict malaria dynamics at a high spatial resolution (i.e., by Fokontany, a cluster of villages) relevant to health care practitioners. Combining generalized linear mixed models (GLMM) and path analyses, we found that socio-economic, land use and climatic variables are all important predictors of monthly malaria incidence at fine spatial scales, via both direct and indirect effects. In addition, out-of-sample predictions from our model were able to identify 58% of the Fokontany in the top quintile for malaria incidence and account for 77% of the variation in the Fokontany incidence rank. These results suggest that it is possible to build a predictive framework using environmental and social predictors that can be complementary to standard surveillance systems and help inform control strategies by field actors at local scales.
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Affiliation(s)
- Julie D Pourtois
- Biology Department, Stanford University, Stanford, CA, United States of America
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States of America
| | - Krti Tallam
- Biology Department, Stanford University, Stanford, CA, United States of America
| | - Isabel Jones
- Biology Department, Stanford University, Stanford, CA, United States of America
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States of America
| | - Elizabeth Hyde
- School of Medicine, Stanford University, Stanford, CA, United States of America
| | - Andrew J Chamberlin
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States of America
| | - Michelle V Evans
- MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France
| | - Felana A Ihantamalala
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA, United States of America
- NGO Pivot, Ifanadiana, Madagascar
| | | | | | - Rado J L Rakotonanahary
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA, United States of America
- NGO Pivot, Ifanadiana, Madagascar
| | | | | | | | - Celestin Razafinjato
- Programme National de Lutte contre le Paludisme, Ministère de la Santé Publique, Antananarivo, Madagascar
| | - Matthew H Bonds
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA, United States of America
- NGO Pivot, Ifanadiana, Madagascar
| | - Giulio A De Leo
- Biology Department, Stanford University, Stanford, CA, United States of America
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States of America
| | - Susanne H Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, CA, United States of America
- Marine Science Institute and Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, United States of America
| | - Andres Garchitorena
- MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France
- NGO Pivot, Ifanadiana, Madagascar
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6
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Sokolow SH, Nova N, Jones IJ, Wood CL, Lafferty KD, Garchitorena A, Hopkins SR, Lund AJ, MacDonald AJ, LeBoa C, Peel AJ, Mordecai EA, Howard ME, Buck JC, Lopez-Carr D, Barry M, Bonds MH, De Leo GA. Ecological and socioeconomic factors associated with the human burden of environmentally mediated pathogens: a global analysis. Lancet Planet Health 2022; 6:e870-e879. [PMID: 36370725 PMCID: PMC9669458 DOI: 10.1016/s2542-5196(22)00248-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 08/22/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Billions of people living in poverty are at risk of environmentally mediated infectious diseases-that is, pathogens with environmental reservoirs that affect disease persistence and control and where environmental control of pathogens can reduce human risk. The complex ecology of these diseases creates a global health problem not easily solved with medical treatment alone. METHODS We quantified the current global disease burden caused by environmentally mediated infectious diseases and used a structural equation model to explore environmental and socioeconomic factors associated with the human burden of environmentally mediated pathogens across all countries. FINDINGS We found that around 80% (455 of 560) of WHO-tracked pathogen species known to infect humans are environmentally mediated, causing about 40% (129 488 of 359 341 disability-adjusted life years) of contemporary infectious disease burden (global loss of 130 million years of healthy life annually). The majority of this environmentally mediated disease burden occurs in tropical countries, and the poorest countries carry the highest burdens across all latitudes. We found weak associations between disease burden and biodiversity or agricultural land use at the global scale. In contrast, the proportion of people with rural poor livelihoods in a country was a strong proximate indicator of environmentally mediated infectious disease burden. Political stability and wealth were associated with improved sanitation, better health care, and lower proportions of rural poverty, indirectly resulting in lower burdens of environmentally mediated infections. Rarely, environmentally mediated pathogens can evolve into global pandemics (eg, HIV, COVID-19) affecting even the wealthiest communities. INTERPRETATION The high and uneven burden of environmentally mediated infections highlights the need for innovative social and ecological interventions to complement biomedical advances in the pursuit of global health and sustainability goals. FUNDING Bill & Melinda Gates Foundation, National Institutes of Health, National Science Foundation, Alfred P. Sloan Foundation, National Institute for Mathematical and Biological Synthesis, Stanford University, and the US Defense Advanced Research Projects Agency.
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Affiliation(s)
- Susanne H Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA; Marine Science Institute, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Nicole Nova
- Department of Biology, Stanford University, Stanford, CA, USA; High Meadows Environmental Institute, Princeton University, Princeton, NJ, USA.
| | - Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - Chelsea L Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
| | - Kevin D Lafferty
- US Geological Survey, Western Ecological Research Center, c/o Marine Science Institute, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Andres Garchitorena
- MIVEGEC, Université Montpellier, Centre National de la Recherche Scientifique, Institut de Recherche pour le Développement, Montpellier, France; PIVOT, Division of Global Health Equity, Brigham and Women's Hospital, Boston, MA, USA
| | | | - Andrea J Lund
- Emmett Interdisciplinary Program in Environment and Resources (E-IPER), Stanford University, Stanford, CA, USA
| | - Andrew J MacDonald
- Department of Biology, Stanford University, Stanford, CA, USA; Earth Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA
| | | | - Alison J Peel
- Centre for Planetary Health and Food Security, Griffith University, Nathan, QLD, Australia
| | - Erin A Mordecai
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Meghan E Howard
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Julia C Buck
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, USA
| | - David Lopez-Carr
- Department of Geography, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Michele Barry
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA; Center for Innovation in Global Health, Stanford University, Stanford, CA, USA
| | - Matthew H Bonds
- PIVOT, Division of Global Health Equity, Brigham and Women's Hospital, Boston, MA, USA; Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA
| | - Giulio A De Leo
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA; Department of Biology, Stanford University, Stanford, CA, USA; Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
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7
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Hopkins SR, Lafferty KD, Wood CL, Olson SH, Buck JC, De Leo GA, Fiorella KJ, Fornberg JL, Garchitorena A, Jones IJ, Kuris AM, Kwong LH, LeBoa C, Leon AE, Lund AJ, MacDonald AJ, Metz DCG, Nova N, Peel AJ, Remais JV, Stewart Merrill TE, Wilson M, Bonds MH, Dobson AP, Lopez Carr D, Howard ME, Mandle L, Sokolow SH. Evidence gaps and diversity among potential win-win solutions for conservation and human infectious disease control. Lancet Planet Health 2022; 6:e694-e705. [PMID: 35932789 PMCID: PMC9364143 DOI: 10.1016/s2542-5196(22)00148-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/21/2022] [Accepted: 06/14/2022] [Indexed: 06/08/2023]
Abstract
As sustainable development practitioners have worked to "ensure healthy lives and promote well-being for all" and "conserve life on land and below water", what progress has been made with win-win interventions that reduce human infectious disease burdens while advancing conservation goals? Using a systematic literature review, we identified 46 proposed solutions, which we then investigated individually using targeted literature reviews. The proposed solutions addressed diverse conservation threats and human infectious diseases, and thus, the proposed interventions varied in scale, costs, and impacts. Some potential solutions had medium-quality to high-quality evidence for previous success in achieving proposed impacts in one or both sectors. However, there were notable evidence gaps within and among solutions, highlighting opportunities for further research and adaptive implementation. Stakeholders seeking win-win interventions can explore this Review and an online database to find and tailor a relevant solution or brainstorm new solutions.
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Affiliation(s)
- Skylar R Hopkins
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, USA; National Center for Ecological Analysis and Synthesis, Santa Barbara, CA, USA.
| | - Kevin D Lafferty
- Western Ecological Research Center, US Geological Survey at Marine Science Institute, University of California, Santa Barbara, CA, USA
| | - Chelsea L Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
| | - Sarah H Olson
- Wildlife Conservation Society, Health Program, Bronx, NY, USA
| | - Julia C Buck
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, USA
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - Kathryn J Fiorella
- Department of Population Medicine and Diagnostic Sciences and Master of Public Health Program, Cornell University, Ithaca, NY, USA
| | - Johanna L Fornberg
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA
| | - Andres Garchitorena
- MIVEGEC, Université Montpellier, Centre National de la Recherche Scientifique, Institut de Recherche pour le Développement, Montpellier, France; NGO PIVOT, Ranomafana, Madagascar
| | - Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - Armand M Kuris
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA
| | - Laura H Kwong
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | | | - Ariel E Leon
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA; US Geological Survey, National Wildlife Health Center, Madison, WI, USA
| | - Andrea J Lund
- Department of Environmental and Occupational Health, University of Colorado School of Public Health, Aurora, CO, USA
| | - Andrew J MacDonald
- Bren School of Environmental Science and Management, University of California, Santa Barbara, CA, USA
| | - Daniel C G Metz
- Scripps Institution of Oceanography, University of California, San Diego, CA, USA
| | - Nicole Nova
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Alison J Peel
- Centre for Planetary Health and Food Security, Griffith University, Nathan, QLD, Australia
| | - Justin V Remais
- Division of Environmental Health Sciences, University of California, Berkeley, CA, USA
| | | | - Maya Wilson
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Matthew H Bonds
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA, USA
| | - Andrew P Dobson
- Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - David Lopez Carr
- Department of Geography, University of California, Santa Barbara, CA, USA
| | - Meghan E Howard
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Lisa Mandle
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | - Susanne H Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
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8
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Hopkins SR, Jones IJ, Buck JC, LeBoa C, Kwong LH, Jacobsen K, Rickards C, Lund AJ, Nova N, MacDonald AJ, Lambert-Peck M, De Leo GA, Sokolow SH. Environmental Persistence of the World's Most Burdensome Infectious and Parasitic Diseases. Front Public Health 2022; 10:892366. [PMID: 35875032 PMCID: PMC9305703 DOI: 10.3389/fpubh.2022.892366] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/30/2022] [Indexed: 11/13/2022] Open
Abstract
Humans live in complex socio-ecological systems where we interact with parasites and pathogens that spend time in abiotic and biotic environmental reservoirs (e.g., water, air, soil, other vertebrate hosts, vectors, intermediate hosts). Through a synthesis of published literature, we reviewed the life cycles and environmental persistence of 150 parasites and pathogens tracked by the World Health Organization's Global Burden of Disease study. We used those data to derive the time spent in each component of a pathogen's life cycle, including total time spent in humans versus all environmental stages. We found that nearly all infectious organisms were “environmentally mediated” to some degree, meaning that they spend time in reservoirs and can be transmitted from those reservoirs to human hosts. Correspondingly, many infectious diseases were primarily controlled through environmental interventions (e.g., vector control, water sanitation), whereas few (14%) were primarily controlled by integrated methods (i.e., combining medical and environmental interventions). Data on critical life history attributes for most of the 150 parasites and pathogens were difficult to find and often uncertain, potentially hampering efforts to predict disease dynamics and model interactions between life cycle time scales and infection control strategies. We hope that this synthetic review and associated database serve as a resource for understanding both common patterns among parasites and pathogens and important variability and uncertainty regarding particular infectious diseases. These insights can be used to improve systems-based approaches for controlling environmentally mediated diseases of humans in an era where the environment is rapidly changing.
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Affiliation(s)
- Skylar R. Hopkins
- National Center for Ecological Analysis and Synthesis, Santa Barbara, CA, United States
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, United States
- *Correspondence: Skylar R. Hopkins
| | - Isabel J. Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States
| | - Julia C. Buck
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, United States
| | - Christopher LeBoa
- Department of Epidemiology, Stanford University, Stanford, CA, United States
| | - Laura H. Kwong
- Stanford Woods Institute for the Environment, Stanford University, Stanford, CA, United States
| | - Kim Jacobsen
- School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Chloe Rickards
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Andrea J. Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, CA, United States
| | - Nicole Nova
- Department of Biology, Stanford University, Stanford, CA, United States
| | - Andrew J. MacDonald
- Department of Biology, Stanford University, Stanford, CA, United States
- Earth Research Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Miles Lambert-Peck
- United Nations University for the Advanced Study of Sustainability, Tokyo, Japan
| | - Giulio A. De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States
| | - Susanne H. Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States
- Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
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9
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Wegner GI, Murray KA, Springmann M, Muller A, Sokolow SH, Saylors K, Morens DM. Averting wildlife-borne infectious disease epidemics requires a focus on socio-ecological drivers and a redesign of the global food system. EClinicalMedicine 2022; 47:101386. [PMID: 35465645 PMCID: PMC9014132 DOI: 10.1016/j.eclinm.2022.101386] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/14/2022] [Accepted: 03/25/2022] [Indexed: 12/20/2022] Open
Abstract
A debate has emerged over the potential socio-ecological drivers of wildlife-origin zoonotic disease outbreaks and emerging infectious disease (EID) events. This Review explores the extent to which the incidence of wildlife-origin infectious disease outbreaks, which are likely to include devastating pandemics like HIV/AIDS and COVID-19, may be linked to excessive and increasing rates of tropical deforestation for agricultural food production and wild meat hunting and trade, which are further related to contemporary ecological crises such as global warming and mass species extinction. Here we explore a set of precautionary responses to wildlife-origin zoonosis threat, including: (a) limiting human encroachment into tropical wildlands by promoting a global transition to diets low in livestock source foods; (b) containing tropical wild meat hunting and trade by curbing urban wild meat demand, while securing access for indigenous people and local communities in remote subsistence areas; and (c) improving biosecurity and other strategies to break zoonosis transmission pathways at the wildlife-human interface and along animal source food supply chains.
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Affiliation(s)
- Giulia I. Wegner
- Wildlife Conservation Research Unit (WildCRU), Department of Zoology, University of Oxford, Tubney House, Abingdon Road, Tubney, Abingdon OX13 5QL, UK
| | - Kris A. Murray
- MRC Unit the Gambia at London School of Hygiene and Tropical Medicine, Fajara, Gambia
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, UK
| | - Marco Springmann
- Oxford Martin Programme on the Future of Food and Nuffield Department of Population Health, University of Oxford, 34 Broad Street, Oxford OX1 3BD, UK
| | - Adrian Muller
- Department of Environmental Systems Science, ETH, Sonneggstrasse 33, Zürich 8092, Switzerland
- Research Institute of Organic Agriculture FiBL, Ackerstrasse 113, Frick 5070, Switzerland
| | - Susanne H. Sokolow
- Stanford Woods Institute for the Environment, Jerry Yang & Akiko Yamazaki Environment & Energy Building, MC 4205, 473 Via Ortega, Stanford, CA 94305, USA
- Marine Science Institute, University of California, Santa Barbara, CA 93106-6150, USA
| | - Karen Saylors
- Labyrinth Global Health, 15th Ave NE, St Petersburg, FL 33704, USA
| | - David M. Morens
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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10
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Agache I, Sampath V, Aguilera J, Akdis CA, Akdis M, Barry M, Bouagnon A, Chinthrajah S, Collins W, Dulitzki C, Erny B, Gomez J, Goshua A, Jutel M, Kizer KW, Kline O, LaBeaud AD, Pali‐Schöll I, Perrett KP, Peters RL, Plaza MP, Prunicki M, Sack T, Salas RN, Sindher SB, Sokolow SH, Thiel C, Veidis E, Wray BD, Traidl‐Hoffmann C, Witt C, Nadeau KC. Climate change and global health: A call to more research and more action. Allergy 2022; 77:1389-1407. [PMID: 35073410 DOI: 10.1111/all.15229] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/06/2022] [Accepted: 01/11/2022] [Indexed: 12/15/2022]
Abstract
There is increasing understanding, globally, that climate change and increased pollution will have a profound and mostly harmful effect on human health. This review brings together international experts to describe both the direct (such as heat waves) and indirect (such as vector-borne disease incidence) health impacts of climate change. These impacts vary depending on vulnerability (i.e., existing diseases) and the international, economic, political, and environmental context. This unique review also expands on these issues to address a third category of potential longer-term impacts on global health: famine, population dislocation, and environmental justice and education. This scholarly resource explores these issues fully, linking them to global health in urban and rural settings in developed and developing countries. The review finishes with a practical discussion of action that health professionals around the world in our field can yet take.
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11
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Jones IJ, Sokolow SH, De Leo GA. Three reasons why expanded use of natural enemy solutions may offer sustainable control of human infections. People Nat (Hoboken) 2022; 4:32-43. [PMID: 35450207 PMCID: PMC9017516 DOI: 10.1002/pan3.10264] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
1. Many infectious pathogens spend a significant portion of their life cycles in the environment or in animal hosts, where ecological interactions with natural enemies may influence pathogen transmission to people. Yet, our understanding of natural enemy opportunities for human disease control is lacking, despite widespread uptake and success of natural enemy solutions for pest and parasite management in agriculture. 2. Here we explore three reasons why conserving, restoring, or augmenting specific natural enemies in the environment could offer a promising complement to conventional clinical strategies to fight environmentally mediated pathogens and parasites. (1) Natural enemies of human infections abound in nature, largely understudied and undiscovered. (2) Natural enemy solutions could provide ecological options for infectious disease control where conventional interventions are lacking. And, (3) Many natural enemy solutions could provide important co-benefits for conservation and human well-being. 3. We illustrate these three arguments with a broad set of examples whereby natural enemies of human infections have been used or proposed to curb human disease burden, with some clear successes. However, the evidence base for most proposed solutions is sparse, and many opportunities likely remain undiscovered, highlighting opportunities for future research.
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Affiliation(s)
- IJ Jones
- Hopkins Marine Station of Stanford University, Pacific Grove, CA, 93950,Corresponding Author: Isabel J. Jones, , 415-309-3125
| | - SH Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, CA, 94305,Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA 93106
| | - GA De Leo
- Hopkins Marine Station of Stanford University, Pacific Grove, CA, 93950,Woods Institute for the Environment, Stanford University, Stanford, CA, 94305
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12
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Forrester JD, Cao S, Schaps D, Liou R, Patil A, Stave C, Sokolow SH, Leo GD. Influence of Socioeconomic and Environmental Determinants of Health on Human Infection and Colonization with Antibiotic-Resistant and Antibiotic-Associated Pathogens: A Scoping Review. Surg Infect (Larchmt) 2022; 23:209-225. [DOI: 10.1089/sur.2021.348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Joseph D. Forrester
- Division of General Surgery, Department of Surgery, Stanford University, Stanford, California, USA
| | - Siqi Cao
- School of Medicine, Stanford University, Stanford, California, USA
| | - Diego Schaps
- School of Medicine, Duke University, Durham, North Carolina, USA
| | - Raymond Liou
- School of Medicine, Stanford University, Stanford, California, USA
| | | | - Christopher Stave
- School of Medicine, Stanford University, Stanford, California, USA
- Lane Medical Library, Stanford University, Stanford, California, USA
| | - Susanne H. Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, California, USA
- Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, USA
| | - Giulio De Leo
- Woods Institute for the Environment, Stanford University, Stanford, California, USA
- Hopkins Marine Station, Stanford University, Stanford, California, USA
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13
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Glidden CK, Nova N, Kain MP, Lagerstrom KM, Skinner EB, Mandle L, Sokolow SH, Plowright RK, Dirzo R, De Leo GA, Mordecai EA. Human-mediated impacts on biodiversity and the consequences for zoonotic disease spillover. Curr Biol 2021; 31:R1342-R1361. [PMID: 34637744 DOI: 10.1016/j.cub.2021.08.070] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Human-mediated changes to natural ecosystems have consequences for both ecosystem and human health. Historically, efforts to preserve or restore 'biodiversity' can seem to be in opposition to human interests. However, the integration of biodiversity conservation and public health has gained significant traction in recent years, and new efforts to identify solutions that benefit both environmental and human health are ongoing. At the forefront of these efforts is an attempt to clarify ways in which biodiversity conservation can help reduce the risk of zoonotic spillover of pathogens from wild animals, sparking epidemics and pandemics in humans and livestock. However, our understanding of the mechanisms by which biodiversity change influences the spillover process is incomplete, limiting the application of integrated strategies aimed at achieving positive outcomes for both conservation and disease management. Here, we review the literature, considering a broad scope of biodiversity dimensions, to identify cases where zoonotic pathogen spillover is mechanistically linked to changes in biodiversity. By reframing the discussion around biodiversity and disease using mechanistic evidence - while encompassing multiple aspects of biodiversity including functional diversity, landscape diversity, phenological diversity, and interaction diversity - we work toward general principles that can guide future research and more effectively integrate the related goals of biodiversity conservation and spillover prevention. We conclude by summarizing how these principles could be used to integrate the goal of spillover prevention into ongoing biodiversity conservation initiatives.
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Affiliation(s)
| | - Nicole Nova
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Morgan P Kain
- Department of Biology, Stanford University, Stanford, CA 94305, USA; Natural Capital Project, Stanford University, Stanford, CA 94305, USA
| | | | - Eloise B Skinner
- Department of Biology, Stanford University, Stanford, CA 94305, USA; Centre for Planetary Health and Food Security, Griffith University, Gold Coast, QLD 4222, Australia
| | - Lisa Mandle
- Department of Biology, Stanford University, Stanford, CA 94305, USA; Natural Capital Project, Stanford University, Stanford, CA 94305, USA; Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA
| | - Susanne H Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA; Marine Science Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Raina K Plowright
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Rodolfo Dirzo
- Department of Biology, Stanford University, Stanford, CA 94305, USA; Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA
| | - Giulio A De Leo
- Department of Biology, Stanford University, Stanford, CA 94305, USA; Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA; Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Erin A Mordecai
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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14
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Lund AJ, Sokolow SH, Jones IJ, Wood CL, Ali S, Chamberlin A, Sy AB, Sam MM, Jouanard N, Schacht AM, Senghor S, Fall A, Ndione R, Riveau G, De Leo GA, López-Carr D. Exposure, hazard, and vulnerability all contribute to Schistosoma haematobium re-infection in northern Senegal. PLoS Negl Trop Dis 2021; 15:e0009806. [PMID: 34610025 PMCID: PMC8525765 DOI: 10.1371/journal.pntd.0009806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 10/19/2021] [Accepted: 09/10/2021] [Indexed: 11/19/2022] Open
Abstract
Background Infectious disease risk is driven by three interrelated components: exposure, hazard, and vulnerability. For schistosomiasis, exposure occurs through contact with water, which is often tied to daily activities. Water contact, however, does not imply risk unless the environmental hazard of snails and parasites is also present in the water. By increasing reliance on hazardous activities and environments, socio-economic vulnerability can hinder reductions in exposure to a hazard. We aimed to quantify the contributions of exposure, hazard, and vulnerability to the presence and intensity of Schistosoma haematobium re-infection. Methodology/Principal findings In 13 villages along the Senegal River, we collected parasitological data from 821 school-aged children, survey data from 411 households where those children resided, and ecological data from all 24 village water access sites. We fit mixed-effects logistic and negative binomial regressions with indices of exposure, hazard, and vulnerability as explanatory variables of Schistosoma haematobium presence and intensity, respectively, controlling for demographic variables. Using multi-model inference to calculate the relative importance of each component of risk, we found that hazard (Ʃwi = 0.95) was the most important component of S. haematobium presence, followed by vulnerability (Ʃwi = 0.91). Exposure (Ʃwi = 1.00) was the most important component of S. haematobium intensity, followed by hazard (Ʃwi = 0.77). Model averaging quantified associations between each infection outcome and indices of exposure, hazard, and vulnerability, revealing a positive association between hazard and infection presence (OR = 1.49, 95% CI 1.12, 1.97), and a positive association between exposure and infection intensity (RR 2.59–3.86, depending on the category; all 95% CIs above 1) Conclusions/Significance Our findings underscore the linkages between social (exposure and vulnerability) and environmental (hazard) processes in the acquisition and accumulation of S. haematobium infection. This approach highlights the importance of implementing both social and environmental interventions to complement mass drug administration. While the impacts of natural hazards tend to be described in terms of social determinants such as exposure and vulnerability, the risk for infectious disease is often expressed in terms of environmental determinants without fully considering the socio-ecological processes that put people in contact with infective agents of disease. In the case of schistosomiasis, risk is determined by human interactions with freshwater environments where schistosome parasites circulate between people and aquatic snails. In this study, we quantified the relative contributions of exposure, hazard, and vulnerability to schistosome re-infection among schoolchildren in an endemic region of northern Senegal. We find that hazard and vulnerability influence whether a child becomes infected, while exposure and hazard influence the burden of worms once infection is acquired. Increasing numbers of worms is known to be positively associated with increasing severity of disease. Our findings underscore the importance of evaluating social and environmental determinants of disease simultaneously; omitting measures of exposure, hazard or vulnerability may limit our understanding of risk.
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Affiliation(s)
- Andrea J. Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, California, United States of America
- * E-mail:
| | - Susanne H. Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - Isabel J. Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Chelsea L. Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, United States of America
| | - Sofia Ali
- Stanford University, Stanford, California, United States of America
| | - Andrew Chamberlin
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Alioune Badara Sy
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
| | - M. Moustapha Sam
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
| | - Nicolas Jouanard
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
- Station d’Innovation Aquacole, Saint Louis, Sénégal
| | - Anne-Marie Schacht
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
- University of Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, Center for Infection and Immunity of Lille, Lille, France
| | - Simon Senghor
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
| | - Assane Fall
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
| | - Raphael Ndione
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
| | - Gilles Riveau
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
- University of Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, Center for Infection and Immunity of Lille, Lille, France
| | - Giulio A. De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - David López-Carr
- Department of Geography, University of California, Santa Barbara, CA, United States of America
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15
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Jones IJ, Sokolow SH, Chamberlin AJ, Lund AJ, Jouanard N, Bandagny L, Ndione R, Senghor S, Schacht AM, Riveau G, Hopkins SR, Rohr JR, Remais JV, Lafferty KD, Kuris AM, Wood CL, De Leo G. Schistosome infection in Senegal is associated with different spatial extents of risk and ecological drivers for Schistosoma haematobium and S. mansoni. PLoS Negl Trop Dis 2021; 15:e0009712. [PMID: 34570777 PMCID: PMC8476036 DOI: 10.1371/journal.pntd.0009712] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 08/06/2021] [Indexed: 11/17/2022] Open
Abstract
Schistosome parasites infect more than 200 million people annually, mostly in sub-Saharan Africa, where people may be co-infected with more than one species of the parasite. Infection risk for any single species is determined, in part, by the distribution of its obligate intermediate host snail. As the World Health Organization reprioritizes snail control to reduce the global burden of schistosomiasis, there is renewed importance in knowing when and where to target those efforts, which could vary by schistosome species. This study estimates factors associated with schistosomiasis risk in 16 villages located in the Senegal River Basin, a region hyperendemic for Schistosoma haematobium and S. mansoni. We first analyzed the spatial distributions of the two schistosomes’ intermediate host snails (Bulinus spp. and Biomphalaria pfeifferi, respectively) at village water access sites. Then, we separately evaluated the relationships between human S. haematobium and S. mansoni infections and (i) the area of remotely-sensed snail habitat across spatial extents ranging from 1 to 120 m from shorelines, and (ii) water access site size and shape characteristics. We compared the influence of snail habitat across spatial extents because, while snail sampling is traditionally done near shorelines, we hypothesized that snails further from shore also contribute to infection risk. We found that, controlling for demographic variables, human risk for S. haematobium infection was positively correlated with snail habitat when snail habitat was measured over a much greater radius from shore (45 m to 120 m) than usual. S. haematobium risk was also associated with large, open water access sites. However, S. mansoni infection risk was associated with small, sheltered water access sites, and was not positively correlated with snail habitat at any spatial sampling radius. Our findings highlight the need to consider different ecological and environmental factors driving the transmission of each schistosome species in co-endemic landscapes. Schistosome parasites infect more than 200 million people worldwide, mainly in sub-Saharan Africa, where many people are at-risk for infection by multiple schistosome species simultaneously. To reduce the global burden of schistosomiasis, control of the parasites’ intermediate host–specific species of freshwater snails–has been elevated in priority to complement mass drug administration campaigns in endemic areas. To maximize the efficacy and efficiency of snail control efforts, a better understanding of where to target intermediate host snails is badly needed. This includes a better understanding of the spatial scale at which snails in the environment contribute to human infection risk, and, in co-endemic settings, how ecological determinants of infection risk vary by schistosome species. We used quantitative snail sampling and remotely-sensed data at 16 villages in the Senegal River Basin to compare and contrast ecological correlates and spatial scales of infection risk from freshwater snails that transmit Schistosoma haematobium versus S. mansoni. We found that infection risk for S. haematobium was associated with snail habitat at a larger spatial radius than is typically considered for schistosomiasis monitoring and control, whereas infection risk for S. mansoni was not positively correlated with snail habitat at any spatial sampling radius, but was associated with small water access sites enclosed by emergent vegetation. Our findings highlight the need to consider the different ecological and environmental factors driving the transmission of each schistosome species in co-endemic landscapes.
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Affiliation(s)
- Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Susanne H Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America.,Stanford Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - Andrew J Chamberlin
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Andrea J Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, California, United States of America
| | - Nicolas Jouanard
- Biomedical Research Center EPLS, Saint-Louis, Senegal.,Station d'Innovation Aquacole, Saint-Louis, Senegal
| | | | | | - Simon Senghor
- Biomedical Research Center EPLS, Saint-Louis, Senegal
| | - Anne-Marie Schacht
- Biomedical Research Center EPLS, Saint-Louis, Senegal.,Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, Lille, France
| | - Gilles Riveau
- Biomedical Research Center EPLS, Saint-Louis, Senegal.,Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, Lille, France
| | - Skylar R Hopkins
- National Center for Ecological Analysis and Synthesis, Santa Barbara, California, United States of America.,Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Jason R Rohr
- Department of Biological Science, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Justin V Remais
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California, United States of America
| | - Kevin D Lafferty
- Western Ecological Research Center, United States Geological Survey at Marine Science Institute, University of California, Santa Barbara, California, United States of America
| | - Armand M Kuris
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California, United States of America
| | - Chelsea L Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, United States of America
| | - Giulio De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America.,Stanford Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
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16
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Tallam K, Liu ZYC, Chamberlin AJ, Jones IJ, Shome P, Riveau G, Ndione RA, Bandagny L, Jouanard N, Eck PV, Ngo T, Sokolow SH, De Leo GA. Identification of Snails and Schistosoma of Medical Importance via Convolutional Neural Networks: A Proof-of-Concept Application for Human Schistosomiasis. Front Public Health 2021; 9:642895. [PMID: 34336754 PMCID: PMC8319642 DOI: 10.3389/fpubh.2021.642895] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 06/08/2021] [Indexed: 11/21/2022] Open
Abstract
In recent decades, computer vision has proven remarkably effective in addressing diverse issues in public health, from determining the diagnosis, prognosis, and treatment of diseases in humans to predicting infectious disease outbreaks. Here, we investigate whether convolutional neural networks (CNNs) can also demonstrate effectiveness in classifying the environmental stages of parasites of public health importance and their invertebrate hosts. We used schistosomiasis as a reference model. Schistosomiasis is a debilitating parasitic disease transmitted to humans via snail intermediate hosts. The parasite affects more than 200 million people in tropical and subtropical regions. We trained our CNN, a feed-forward neural network, on a limited dataset of 5,500 images of snails and 5,100 images of cercariae obtained from schistosomiasis transmission sites in the Senegal River Basin, a region in western Africa that is hyper-endemic for the disease. The image set included both images of two snail genera that are relevant to schistosomiasis transmission – that is, Bulinus spp. and Biomphalaria pfeifferi – as well as snail images that are non-component hosts for human schistosomiasis. Cercariae shed from Bi. pfeifferi and Bulinus spp. snails were classified into 11 categories, of which only two, S. haematobium and S. mansoni, are major etiological agents of human schistosomiasis. The algorithms, trained on 80% of the snail and parasite dataset, achieved 99% and 91% accuracy for snail and parasite classification, respectively, when used on the hold-out validation dataset – a performance comparable to that of experienced parasitologists. The promising results of this proof-of-concept study suggests that this CNN model, and potentially similar replicable models, have the potential to support the classification of snails and parasite of medical importance. In remote field settings where machine learning algorithms can be deployed on cost-effective and widely used mobile devices, such as smartphones, these models can be a valuable complement to laboratory identification by trained technicians. Future efforts must be dedicated to increasing dataset sizes for model training and validation, as well as testing these algorithms in diverse transmission settings and geographies.
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Affiliation(s)
- Krti Tallam
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States
| | - Zac Yung-Chun Liu
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States
| | - Andrew J Chamberlin
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States
| | - Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States
| | - Pretom Shome
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States
| | - Gilles Riveau
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal.,Univ Lille, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre Hospitalier Universitaire (CHU) Lille, Institut Pasteur de Lille, U1019-Unité Mixte de Recherche (UMR) 9017-CIIL-Center for Infection and Immunity of Lille, Lille, France
| | - Raphael A Ndione
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Lydie Bandagny
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Nicolas Jouanard
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal.,Station d'Innovation Aquacole (SIA), à Université Gaston Berger, Saint-Louis, Senegal
| | - Paul Van Eck
- International Business Machines Corporation (IBM) Silicon Valley Lab, San Jose, CA, United States
| | - Ton Ngo
- International Business Machines Corporation (IBM) Silicon Valley Lab, San Jose, CA, United States
| | - Susanne H Sokolow
- International Business Machines Corporation (IBM) Silicon Valley Lab, San Jose, CA, United States.,Department of Ecology Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States.,Woods Institute for the Environment, Stanford University, Pacific Grove, CA, United States
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17
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Lund AJ, Rehkopf DH, Sokolow SH, Sam MM, Jouanard N, Schacht AM, Senghor S, Fall A, Riveau G, De Leo GA, Lopez-Carr D. Land use impacts on parasitic infection: a cross-sectional epidemiological study on the role of irrigated agriculture in schistosome infection in a dammed landscape. Infect Dis Poverty 2021; 10:35. [PMID: 33745442 PMCID: PMC7983278 DOI: 10.1186/s40249-021-00816-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 03/05/2021] [Indexed: 01/20/2023] Open
Abstract
Background Water resources development promotes agricultural expansion and food security. But are these benefits offset by increased infectious disease risk? Dam construction on the Senegal River in 1986 was followed by agricultural expansion and increased transmission of human schistosomes. Yet the mechanisms linking these two processes at the individual and household levels remain unclear. We investigated the association between household land use and schistosome infection in children. Methods We analyzed cross-sectional household survey data (n = 655) collected in 16 rural villages in August 2016 across demographic, socio-economic and land use dimensions, which were matched to Schistosoma haematobium (n = 1232) and S. mansoni (n = 1222) infection data collected from school-aged children. Mixed effects regression determined the relationship between irrigated area and schistosome infection presence and intensity. Results Controlling for socio-economic and demographic risk factors, irrigated area cultivated by a household was associated with an increase in the presence of S. haematobium infection (odds ratio [OR] = 1.14; 95% confidence interval [95% CI]: 1.03–1.28) but not S. mansoni infection (OR = 1.02; 95% CI: 0.93–1.11). Associations between infection intensity and irrigated area were positive but imprecise (S. haematobium: rate ratio [RR] = 1.05; 95% CI: 0.98–1.13, S. mansoni: RR = 1.09; 95% CI: 0.89–1.32). Conclusions Household engagement in irrigated agriculture increases individual risk of S. haematobium but not S. mansoni infection. Increased contact with irrigated landscapes likely drives exposure, with greater impacts on households relying on agricultural livelihoods.![]() Supplementary Information The online version contains supplementary material available at 10.1186/s40249-021-00816-5.
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Affiliation(s)
- Andrea J Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, 473 Via Ortega Suite 226, Stanford, CA, USA.
| | - David H Rehkopf
- Department of Epidemiology and Population Health, Stanford University School of Medicine, Stanford University, 1701 Page Mill Road Room 229, Palo Alto, CA, USA
| | - Susanne H Sokolow
- Woods Institute for the Environment, Stanford University, 473 Via Ortega, Stanford, CA, USA.,Hopkins Marine Station, Stanford University, 120 Ocean View Blvd, Pacific Grove, CA, USA
| | - M Moustapha Sam
- Centre de Recherche Biomédicale-Espoir Pour La Sante, 263 Route de la Corniche, BP 226, Saint-Louis, Sénégal
| | - Nicolas Jouanard
- Station d'Innovation Aquacole, UGB Cote Cite SAED, BP 524, Saint-Louis, Sénégal.,Center for Infection and Immunology of Lille, Institut Pasteur de Lille, 1 Rue du Professeur Calmette, 59800, Lille, France
| | - Anne-Marie Schacht
- Centre de Recherche Biomédicale-Espoir Pour La Sante, 263 Route de la Corniche, BP 226, Saint-Louis, Sénégal.,Center for Infection and Immunology of Lille, Institut Pasteur de Lille, 1 Rue du Professeur Calmette, 59800, Lille, France
| | - Simon Senghor
- Centre de Recherche Biomédicale-Espoir Pour La Sante, 263 Route de la Corniche, BP 226, Saint-Louis, Sénégal
| | - Assane Fall
- Centre de Recherche Biomédicale-Espoir Pour La Sante, 263 Route de la Corniche, BP 226, Saint-Louis, Sénégal
| | - Gilles Riveau
- Centre de Recherche Biomédicale-Espoir Pour La Sante, 263 Route de la Corniche, BP 226, Saint-Louis, Sénégal.,Center for Infection and Immunology of Lille, Institut Pasteur de Lille, 1 Rue du Professeur Calmette, 59800, Lille, France
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, 120 Ocean View Blvd, Pacific Grove, CA, USA
| | - David Lopez-Carr
- Department of Geography, University of California, 4836 Ellison Hall, Santa Barbara, CA, USA
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18
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Chamberlin AJ, Jones IJ, Lund AJ, Jouanard N, Riveau G, Ndione R, Sokolow SH, Wood CL, Lafferty KD, De Leo GA. Visualization of schistosomiasis snail habitats using light unmanned aerial vehicles. Geospat Health 2021; 15. [PMID: 33461284 DOI: 10.4081/gh.2020.818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 02/13/2020] [Indexed: 06/12/2023]
Abstract
Schistosomiasis, or "snail fever", is a parasitic disease affecting over 200 million people worldwide. People become infected when exposed to water containing particular species of freshwater snails. Habitats for such snails can be mapped using lightweight, inexpensive and field-deployable consumer-grade Unmanned Aerial Vehicles (UAVs), also known as drones. Drones can obtain imagery in remote areas with poor satellite imagery. An unexpected outcome of using drones is public engagement. Whereas sampling snails exposes field technicians to infection risk and might disturb locals who are also using the water site, drones are novel and fun to watch, attracting crowds that can be educated about the infection risk.
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Affiliation(s)
| | - Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, CA.
| | - Andrea J Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, CA.
| | - Nicolas Jouanard
- Biomedical Research Center EPLS, Saint Louis; Station d'Innovation Aquacole, Saint Louis.
| | | | | | | | - Chelsea L Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA.
| | - Kevin D Lafferty
- Western Ecological Research Center, United States Geological Survey; Marine Science Institute, University of California, Santa Barbara, CA.
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA.
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19
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Jones IJ, MacDonald AJ, Hopkins SR, Lund AJ, Liu ZYC, Fawzi NI, Purba MP, Fankhauser K, Chamberlin AJ, Nirmala M, Blundell AG, Emerson A, Jennings J, Gaffikin L, Barry M, Lopez-Carr D, Webb K, De Leo GA, Sokolow SH. Improving rural health care reduces illegal logging and conserves carbon in a tropical forest. Proc Natl Acad Sci U S A 2020; 117:28515-28524. [PMID: 33106399 PMCID: PMC7668090 DOI: 10.1073/pnas.2009240117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Tropical forest loss currently exceeds forest gain, leading to a net greenhouse gas emission that exacerbates global climate change. This has sparked scientific debate on how to achieve natural climate solutions. Central to this debate is whether sustainably managing forests and protected areas will deliver global climate mitigation benefits, while ensuring local peoples' health and well-being. Here, we evaluate the 10-y impact of a human-centered solution to achieve natural climate mitigation through reductions in illegal logging in rural Borneo: an intervention aimed at expanding health care access and use for communities living near a national park, with clinic discounts offsetting costs historically met through illegal logging. Conservation, education, and alternative livelihood programs were also offered. We hypothesized that this would lead to improved health and well-being, while also alleviating illegal logging activity within the protected forest. We estimated that 27.4 km2 of deforestation was averted in the national park over a decade (∼70% reduction in deforestation compared to a synthetic control, permuted P = 0.038). Concurrently, the intervention provided health care access to more than 28,400 unique patients, with clinic usage and patient visitation frequency highest in communities participating in the intervention. Finally, we observed a dose-response in forest change rate to intervention engagement (person-contacts with intervention activities) across communities bordering the park: The greatest logging reductions were adjacent to the most highly engaged villages. Results suggest that this community-derived solution simultaneously improved health care access for local and indigenous communities and sustainably conserved carbon stocks in a protected tropical forest.
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Affiliation(s)
- Isabel J Jones
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA 93950;
| | - Andrew J MacDonald
- Department of Biology, Stanford University, Stanford, CA 94305
- Earth Research Institute, University of California, Santa Barbara, CA 93106
- Bren School of Environmental Science and Management, University of California, Santa Barbara, CA 93106
| | - Skylar R Hopkins
- National Center for Ecological Analysis and Synthesis, Santa Barbara, CA 93101
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27607
| | - Andrea J Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, CA 94305
| | - Zac Yung-Chun Liu
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA 93950
| | | | | | - Katie Fankhauser
- Oregon Health and Science University, School of Public Health, Portland, OR 97239
| | - Andrew J Chamberlin
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA 93950
| | - Monica Nirmala
- Alam Sehat Lestari, Sukadana, West Kalimantan 78852, Indonesia
| | | | | | | | - Lynne Gaffikin
- Department of Obstetrics and Gynecology, Stanford University, Stanford, CA 94305
- Center for Innovation in Global Health, Stanford University, Stanford, CA 94305
| | - Michele Barry
- Center for Innovation in Global Health, Stanford University, Stanford, CA 94305
| | - David Lopez-Carr
- Department of Geography, University of California, Santa Barbara, CA 93117
| | | | - Giulio A De Leo
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA 93950
- Woods Institute for the Environment, Stanford University, Stanford, CA 94305
| | - Susanne H Sokolow
- Center for Innovation in Global Health, Stanford University, Stanford, CA 94305;
- Woods Institute for the Environment, Stanford University, Stanford, CA 94305
- Marine Science Institute, University of California, Santa Barbara, CA 93106
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20
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Castonguay FM, Sokolow SH, De Leo GA, Sanchirico JN. Cost-effectiveness of combining drug and environmental treatments for environmentally transmitted diseases. Proc Biol Sci 2020; 287:20200966. [PMID: 32842925 PMCID: PMC7482273 DOI: 10.1098/rspb.2020.0966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 08/03/2020] [Indexed: 01/13/2023] Open
Abstract
Control of neglected tropical diseases (NTDs) via mass drug administration (MDA) has increased considerably over the past decade, but strategies focused exclusively on human treatment show limited efficacy. This paper investigated trade-offs between drug and environmental treatments in the fight against NTDs by using schistosomiasis as a case study. We use optimal control techniques where the planner's objective is to treat the disease over a time horizon at the lowest possible total cost, where the total costs include treatment, transportation and damages (reduction in human health). We show that combining environmental treatments and drug treatments reduces the dependency on MDAs and that this reduction increases when the planners take a longer-run perspective on the fight to reduce NTDs. Our results suggest that NTDs with environmental reservoirs require moving away from a reliance solely on MDA to integrated treatment involving investment in both drug and environmental controls.
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Affiliation(s)
- François M. Castonguay
- Department of Agricultural and Resource Economics, University of California, Davis, Davis, CA 95616, USA
| | - Susanne H. Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
- Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA
- Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Giulio A. De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
- Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - James N. Sanchirico
- Department of Environmental Science and Policy, University of California, Davis, Davis, CA 95616, USA
- Resources for the Future, Washington, DC 20036, USA
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21
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Haggerty CJE, Bakhoum S, Civitello DJ, De Leo GA, Jouanard N, Ndione RA, Remais JV, Riveau G, Senghor S, Sokolow SH, Sow S, Wolfe C, Wood CL, Jones I, Chamberlin AJ, Rohr JR. Aquatic macrophytes and macroinvertebrate predators affect densities of snail hosts and local production of schistosome cercariae that cause human schistosomiasis. PLoS Negl Trop Dis 2020; 14:e0008417. [PMID: 32628666 PMCID: PMC7365472 DOI: 10.1371/journal.pntd.0008417] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/16/2020] [Accepted: 05/22/2020] [Indexed: 12/22/2022] Open
Abstract
Background Schistosomiasis is responsible for the second highest burden of disease among neglected tropical diseases globally, with over 90 percent of cases occurring in African regions where drugs to treat the disease are only sporadically available. Additionally, human re-infection after treatment can be a problem where there are high numbers of infected snails in the environment. Recent experiments indicate that aquatic factors, including plants, nutrients, or predators, can influence snail abundance and parasite production within infected snails, both components of human risk. This study investigated how snail host abundance and release of cercariae (the free swimming stage infective to humans) varies at water access sites in an endemic region in Senegal, a setting where human schistosomiasis prevalence is among the highest globally. Methods/Principal findings We collected snail intermediate hosts at 15 random points stratified by three habitat types at 36 water access sites, and counted cercarial production by each snail after transfer to the laboratory on the same day. We found that aquatic vegetation was positively associated with per-capita cercarial release by snails, probably because macrophytes harbor periphyton resources that snails feed upon, and well-fed snails tend to produce more parasites. In contrast, the abundance of aquatic macroinvertebrate snail predators was negatively associated with per-capita cercarial release by snails, probably because of several potential sublethal effects on snails or snail infection, despite a positive association between snail predators and total snail numbers at a site, possibly due to shared habitat usage or prey tracking by the predators. Thus, complex bottom-up and top-down ecological effects in this region plausibly influence the snail shedding rate and thus, total local density of schistosome cercariae. Conclusions/Significance Our study suggests that aquatic macrophytes and snail predators can influence per-capita cercarial production and total abundance of snails. Thus, snail control efforts might benefit by targeting specific snail habitats where parasite production is greatest. In conclusion, a better understanding of top-down and bottom-up ecological factors that regulate densities of cercarial release by snails, rather than solely snail densities or snail infection prevalence, might facilitate improved schistosomiasis control. Over 800 million people are at risk of schistosomiasis and environmental factors that regulate densities of cercariae parasites that infect humans remain poorly understood. We sampled a spatially extensive area at 36 water-access points in northern Senegal, and quantified densities of snail intermediate hosts, snail predators, and aquatic vegetation in each sample, as well as cercariae released from snails after they were brought to the laboratory. We found that the quantity of submerged aquatic vegetation, particularly Ceratophyllum spp., was positively associated with schistosome cercariae released per infected snail, and total potential cercariae released by the collected snails per water access site. In contrast, the abundance of aquatic predators near infected snails (in the same sweep) was negatively associated with the per-capita cercarial release by infected snails, but positively associated with total snail abundance per site. Additionally, snail densities and potential cercarial densities (estimated as the sum of cercariae released by all collected, infected snails at a site) were only weakly correlated, suggesting that snail densities alone might not accurately reflect total potential of those snails to emit schistosome cercariae. Overall, a better understanding of aquatic factors that can influence the production of schistosome cercariae under field conditions, rather than snail host abundance alone, might facilitate improvements in schistosomiasis monitoring and control.
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Affiliation(s)
- Christopher J. E. Haggerty
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- Department of Integrative Biology, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
| | | | - David J. Civitello
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Giulio A. De Leo
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Nicolas Jouanard
- Station d'Innovation Aquacole, Saint-Louis, Senegal
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Raphael A. Ndione
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Justin V. Remais
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California, United States of America
| | - Gilles Riveau
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
- Institut Pasteur de Lille—CIIL, France
| | - Simon Senghor
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Susanne H. Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - Souleymane Sow
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Caitlin Wolfe
- College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Chelsea L. Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, United States of America
| | - Isabel Jones
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Andrew J. Chamberlin
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Jason R. Rohr
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- Department of Integrative Biology, University of South Florida, Tampa, Florida, United States of America
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22
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Hoover CM, Sokolow SH, Kemp J, Sanchirico JN, Lund AJ, Jones IJ, Higginson T, Riveau G, Savaya A, Coyle S, Wood CL, Micheli F, Casagrandi R, Mari L, Gatto M, Rinaldo A, Perez-Saez J, Rohr JR, Sagi A, Remais JV, De Leo GA. Modelled effects of prawn aquaculture on poverty alleviation and schistosomiasis control. Nat Sustain 2020; 2:611-620. [PMID: 33313425 PMCID: PMC7731924 DOI: 10.1038/s41893-019-0301-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 04/26/2019] [Indexed: 05/23/2023]
Abstract
Recent evidence suggests that snail predators may aid efforts to control the human parasitic disease schistosomiasis by eating aquatic snail species that serve as intermediate hosts of the parasite. Potential synergies between schistosomiasis control and aquaculture of giant prawns are evaluated using an integrated bio-economic-epidemiologic model. Combinations of stocking density and aquaculture cycle length that maximize cumulative, discounted profit are identified for two prawn species in sub-Saharan Africa: the endemic, non-domesticated Macrobrachium vollenhovenii, and the non-native, domesticated Macrobrachium rosenbergii. At profit maximizing densities, both M. rosenbergii and M. vollenhovenii may substantially reduce intermediate host snail populations and aid schistosomiasis control efforts. Control strategies drawing on both prawn aquaculture to reduce intermediate host snail populations and mass drug administration to treat infected individuals are found to be superior to either strategy alone. Integrated aquaculture-based interventions can be a win-win strategy in terms of health and sustainable development in schistosomiasis endemic regions of the world.
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Affiliation(s)
- Christopher M. Hoover
- Division of Environmental Health Sciences, University of California, Berkeley School of Public Health, Berkeley, CA 94720 USA
| | - Susanne H. Sokolow
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950 USA
- Woods Institute for the Environment and Center for Innovation in Global Health, Stanford University, Stanford, CA 94305 USA
| | - Jonas Kemp
- Program in Human Biology, Stanford University, Stanford, CA 94305 USA
| | - James N. Sanchirico
- Department of Environmental Science and Policy, University of California, Davis, Davis, CA 95616 USA
| | - Andrea J. Lund
- Emmett Interdisciplinary Program in Environment and Resources, School of Earth, Energy and Environmental Sciences, Stanford University, Stanford, CA 94305 USA
| | - Isabel J. Jones
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950 USA
| | - Tyler Higginson
- Middlebury Institute of International Studies at Monterey, Monterey, CA 93940 USA
| | - Gilles Riveau
- Biomedical Research Center EPLS, Saint Louis, Senegal
| | - Amit Savaya
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Shawn Coyle
- Kentucky State University, Aquaculture Division, Aquaculture Research Center, Frankfort, KY 40601 USA
| | - Chelsea L. Wood
- University of Washington, School of Aquatic and Fishery Sciences, Seattle, WA 98195 USA
| | - Fiorenza Micheli
- Hopkins Marine Station and Center for Ocean Solutions, Stanford University, Pacific Grove, CA 93950 USA
| | - Renato Casagrandi
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
| | - Lorenzo Mari
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
| | - Marino Gatto
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
| | - Andrea Rinaldo
- Laboratory of Ecohydrology, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Switzerland
| | - Javier Perez-Saez
- Laboratory of Ecohydrology, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Switzerland
| | - Jason R. Rohr
- Department of Biological Sciences, Eck Institute of Global Health, Environmental Change Initiative University of Notre Damea, Notre Dame, IN, 46556 USA
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620 USA
| | - Amir Sagi
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Justin V. Remais
- Division of Environmental Health Sciences, University of California, Berkeley School of Public Health, Berkeley, CA 94720 USA
| | - Giulio A. De Leo
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950 USA
- Woods Institute for the Environment and Center for Innovation in Global Health, Stanford University, Stanford, CA 94305 USA
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23
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Hoover CM, Rumschlag SL, Strgar L, Arakala A, Gambhir M, de Leo GA, Sokolow SH, Rohr JR, Remais JV. Effects of agrochemical pollution on schistosomiasis transmission: a systematic review and modelling analysis. Lancet Planet Health 2020; 4:e280-e291. [PMID: 32681899 PMCID: PMC7754781 DOI: 10.1016/s2542-5196(20)30105-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Agrochemical pollution of surface waters is a growing global environmental challenge, especially in areas where agriculture is rapidly expanding and intensifying. Agrochemicals might affect schistosomiasis transmission through direct and indirect effects on Schistosoma parasites, their intermediate snail hosts, snail predators, and snail algal resources. We aimed to review and summarise the effects of these agrochemicals on schistosomiasis transmission dynamics. METHODS We did a systematic review of agrochemical effects on the lifecycle of Schistosoma spp and fitted dose-response models to data regarding the association between components of the lifecycle and agrochemical concentrations. We incorporated these dose-response functions and environmentally relevant concentrations of agrochemicals into a mathematical model to estimate agrochemical effects on schistosomiasis transmission. Dose-response functions were used to estimate individual agrochemical effects on estimates of the agrochemically influenced basic reproduction number, R0, for Schistosoma haematobium. We incorporated time series of environmentally relevant agrochemical concentrations into the model and simulated mass drug administration control efforts in the presence of agrochemicals. FINDINGS We derived 120 dose-response functions describing the effects of agrochemicals on schistosome lifecycle components. The median estimate of the basic reproduction number under agrochemical-free conditions, was 1·65 (IQR 1·47-1·79). Agrochemical effects on estimates of R0 for S haematobium ranged from a median three-times increase (R0 5·05, IQR 4·06-5·97) to transmission elimination (R0 0). Simulations of transmission dynamics subject to interacting annual mass drug administration and agrochemical pollution yielded a median estimate of 64·82 disability-adjusted life-years (DALYs) lost per 100 000 people per year (IQR 62·52-67·68) attributable to atrazine use. In areas where aquatic arthropod predators of intermediate host snails suppress transmission, the insecticides chlorpyrifos (6·82 DALYs lost per 100 000 people per year, IQR 4·13-8·69) and profenofos (103·06 DALYs lost per 100 000 people per year, IQR 89·63-104·90) might also increase the disability burden through their toxic effects on arthropods. INTERPRETATION Expected environmental concentrations of agrochemicals alter schistosomiasis transmission through direct and indirect effects on intermediate host and parasite densities. As industrial agricultural practices expand in areas where schistosomiasis is endemic, strategies to prevent increases in transmission due to agrochemical pollution should be developed and pursued. FUNDING National Science Foundation, National Institutes of Health.
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Affiliation(s)
- Christopher M Hoover
- Division of Environmental Health Sciences, Berkeley School of Public Health, University of California, Berkeley, Berkeley, CA, USA
| | - Samantha L Rumschlag
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Luke Strgar
- Division of Environmental Health Sciences, Berkeley School of Public Health, University of California, Berkeley, Berkeley, CA, USA
| | - Arathi Arakala
- Discipline of Mathematics, School of Sciences, Royal Melbourne Institute of Technology University, Melbourne, VIC, Australia
| | | | - Giulio A de Leo
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA; Woods Institute for the Environment and Center for Innovation in Global Health, Stanford University, Stanford, CA, USA
| | - Susanne H Sokolow
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA; Woods Institute for the Environment and Center for Innovation in Global Health, Stanford University, Stanford, CA, USA
| | - Jason R Rohr
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Justin V Remais
- Division of Environmental Health Sciences, Berkeley School of Public Health, University of California, Berkeley, Berkeley, CA, USA.
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24
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Buck JC, De Leo GA, Sokolow SH. Concomitant Immunity and Worm Senescence May Drive Schistosomiasis Epidemiological Patterns: An Eco-Evolutionary Perspective. Front Immunol 2020; 11:160. [PMID: 32161583 PMCID: PMC7053360 DOI: 10.3389/fimmu.2020.00160] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/21/2020] [Indexed: 11/13/2022] Open
Abstract
In areas where human schistosomiasis is endemic, infection prevalence and egg output are known to rise rapidly through childhood, reach a peak at 8-15 years of age, and decline thereafter. A similar peak ("overshoot") followed by return to equilibrium infection levels sometimes occurs a year or less after mass drug administration. These patterns are usually assumed to be due to acquired immunity, which is induced by exposure, directed by the host's immune system, and develops slowly over the lifetime of the host. Other explanations that have been advanced previously include differential exposure of hosts, differential mortality of hosts, and progressive pathology. Here we review these explanations and offer a novel (but not mutually exclusive) explanation, namely that adult worms protect the host against larval stages for their own benefit ("concomitant immunity") and that worm fecundity declines with worm age ("reproductive senescence"). This explanation approaches schistosomiasis from an eco-evolutionary perspective, as concomitant immunity maximizes the fitness of adult worms by reducing intraspecific competition within the host. If correct, our hypothesis could have profound implications for treatment and control of human schistosomiasis. Specifically, if immunity is worm-directed, then treatment of long-standing infections comprised of old senescent worms could enable infection with new, highly fecund worms. Furthermore, our hypothesis suggests revisiting research on therapeutics that mimic the concomitant immunity-modulating activity of adult worms, while minimizing pathological consequences of their eggs. We emphasize the value of an eco-evolutionary perspective on host-parasite interactions.
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Affiliation(s)
- Julia C. Buck
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, United States
| | - Giulio A. De Leo
- Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA, United States
- Woods Institute for the Environment, Stanford University, Stanford, CA, United States
| | - Susanne H. Sokolow
- Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA, United States
- Woods Institute for the Environment, Stanford University, Stanford, CA, United States
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Maier T, Wheeler NJ, Namigai EKO, Tycko J, Grewelle RE, Woldeamanuel Y, Klohe K, Perez-Saez J, Sokolow SH, De Leo GA, Yoshino TP, Zamanian M, Reinhard-Rupp J. Gene drives for schistosomiasis transmission control. PLoS Negl Trop Dis 2019; 13:e0007833. [PMID: 31856157 PMCID: PMC6922350 DOI: 10.1371/journal.pntd.0007833] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Schistosomiasis is one of the most important and widespread neglected tropical diseases (NTD), with over 200 million people infected in more than 70 countries; the disease has nearly 800 million people at risk in endemic areas. Although mass drug administration is a cost-effective approach to reduce occurrence, extent, and severity of the disease, it does not provide protection to subsequent reinfection. Interventions that target the parasites’ intermediate snail hosts are a crucial part of the integrated strategy required to move toward disease elimination. The recent revolution in gene drive technology naturally leads to questions about whether gene drives could be used to efficiently spread schistosome resistance traits in a population of snails and whether gene drives have the potential to contribute to reduced disease transmission in the long run. Responsible implementation of gene drives will require solutions to complex challenges spanning multiple disciplines, from biology to policy. This Review Article presents collected perspectives from practitioners of global health, genome engineering, epidemiology, and snail/schistosome biology and outlines strategies for responsible gene drive technology development, impact measurements of gene drives for schistosomiasis control, and gene drive governance. Success in this arena is a function of many factors, including gene-editing specificity and efficiency, the level of resistance conferred by the gene drive, how fast gene drives may spread in a metapopulation over a complex landscape, ecological sustainability, social equity, and, ultimately, the reduction of infection prevalence in humans. With combined efforts from across the broad global health community, gene drives for schistosomiasis control could fortify our defenses against this devastating disease in the future.
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Affiliation(s)
- Theresa Maier
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom
| | - Nicolas James Wheeler
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Global Health Institute of Merck (KGaA), Eysins, Switzerland
| | | | - Josh Tycko
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Richard Ernest Grewelle
- Hopkins Marine Station, School of Humanities and Sciences, Stanford University, Pacific Grove, California, United States of America
| | - Yimtubezinash Woldeamanuel
- Department of Microbiology, Immunology & Parasitology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | | | - Javier Perez-Saez
- Laboratory of Ecohydrology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Susanne H. Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
- Marine Science Institute, University of California, Santa Barbara, California, United States of America
| | - Giulio A. De Leo
- Hopkins Marine Station, School of Humanities and Sciences, Stanford University, Pacific Grove, California, United States of America
| | - Timothy P. Yoshino
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Mostafa Zamanian
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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Wood CL, Sokolow SH, Jones IJ, Chamberlin AJ, Lafferty KD, Kuris AM, Jocque M, Hopkins S, Adams G, Buck JC, Lund AJ, Garcia-Vedrenne AE, Fiorenza E, Rohr JR, Allan F, Webster B, Rabone M, Webster JP, Bandagny L, Ndione R, Senghor S, Schacht AM, Jouanard N, Riveau G, De Leo GA. Precision mapping of snail habitat provides a powerful indicator of human schistosomiasis transmission. Proc Natl Acad Sci U S A 2019; 116:23182-23191. [PMID: 31659025 PMCID: PMC6859407 DOI: 10.1073/pnas.1903698116] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Recently, the World Health Organization recognized that efforts to interrupt schistosomiasis transmission through mass drug administration have been ineffective in some regions; one of their new recommended strategies for global schistosomiasis control emphasizes targeting the freshwater snails that transmit schistosome parasites. We sought to identify robust indicators that would enable precision targeting of these snails. At the site of the world's largest recorded schistosomiasis epidemic-the Lower Senegal River Basin in Senegal-intensive sampling revealed positive relationships between intermediate host snails (abundance, density, and prevalence) and human urogenital schistosomiasis reinfection (prevalence and intensity in schoolchildren after drug administration). However, we also found that snail distributions were so patchy in space and time that obtaining useful data required effort that exceeds what is feasible in standard monitoring and control campaigns. Instead, we identified several environmental proxies that were more effective than snail variables for predicting human infection: the area covered by suitable snail habitat (i.e., floating, nonemergent vegetation), the percent cover by suitable snail habitat, and size of the water contact area. Unlike snail surveys, which require hundreds of person-hours per site to conduct, habitat coverage and site area can be quickly estimated with drone or satellite imagery. This, in turn, makes possible large-scale, high-resolution estimation of human urogenital schistosomiasis risk to support targeting of both mass drug administration and snail control efforts.
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Affiliation(s)
- Chelsea L Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195;
| | - Susanne H Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950
| | - Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950
| | | | - Kevin D Lafferty
- Western Ecological Research Center, United States Geological Survey, Santa Barbara, CA 93106
- Marine Science Institute, University of California, Santa Barbara, CA 93106
| | - Armand M Kuris
- Marine Science Institute, University of California, Santa Barbara, CA 93106
| | - Merlijn Jocque
- Aquatic and Terrestrial Ecology, Royal Belgian Institute of Natural Sciences, 1000 Brussels, Belgium
| | - Skylar Hopkins
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
| | - Grant Adams
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195
| | - Julia C Buck
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC 28403
| | - Andrea J Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, CA 94305
| | - Ana E Garcia-Vedrenne
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095
| | - Evan Fiorenza
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195
| | - Jason R Rohr
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN 46556
| | - Fiona Allan
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
- London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
| | - Bonnie Webster
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
- London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
| | - Muriel Rabone
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
- London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
| | - Joanne P Webster
- London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
- Centre for Emerging, Endemic, and Exotic Diseases, Department of Pathology and Population Sciences, Royal Veterinary College, University of London, London NW1 0TU, United Kingdom
| | - Lydie Bandagny
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
| | - Raphaël Ndione
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
| | - Simon Senghor
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
| | - Anne-Marie Schacht
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
| | - Nicolas Jouanard
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
- Station d'Innovation Aquacole, BP 524 Saint-Louis, Senegal
| | - Gilles Riveau
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950
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Lund AJ, Sam MM, Sy AB, Sow OW, Ali S, Sokolow SH, Bereknyei Merrell S, Bruce J, Jouanard N, Senghor S, Riveau G, Lopez-Carr D, De Leo GA. Unavoidable Risks: Local Perspectives on Water Contact Behavior and Implications for Schistosomiasis Control in an Agricultural Region of Northern Senegal. Am J Trop Med Hyg 2019; 101:837-847. [PMID: 31452497 PMCID: PMC6779182 DOI: 10.4269/ajtmh.19-0099] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 06/24/2019] [Indexed: 12/31/2022] Open
Abstract
Human schistosomiasis is a snail-borne parasitic disease affecting more than 200 million people worldwide. Direct contact with snail-infested freshwater is the primary route of exposure. Water management infrastructure, including dams and irrigation schemes, expands snail habitat, increasing the risk across the landscape. The Diama Dam, built on the lower basin of the Senegal River to prevent saltwater intrusion and promote year-round agriculture in the drought-prone Sahel, is a paradigmatic case. Since dam completion in 1986, the rural population-whose livelihoods rely mostly on agriculture-has suffered high rates of schistosome infection. The region remains one of the most hyperendemic regions in the world. Because of the convergence between livelihoods and environmental conditions favorable to transmission, schistosomiasis is considered an illustrative case of a disease-driven poverty trap (DDPT). The literature to date on the topic, however, remains largely theoretical. With qualitative data generated from 12 focus groups in four villages, we conducted team-based theme analysis to investigate how perception of schistosomiasis risk and reported preventive behaviors may suggest the presence of a DDPT. Our analysis reveals three key findings: 1) rural villagers understand schistosomiasis risk (i.e., where and when infections occur), 2) accordingly, they adopt some preventive behaviors, but ultimately, 3) exposure persists, because of circumstances characteristic of rural livelihoods. These findings highlight the capacity of local populations to participate actively in schistosomiasis control programs and the limitations of widespread drug treatment campaigns. Interventions that target the environmental reservoir of disease may provide opportunities to reduce exposure while maintaining resource-dependent livelihoods.
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Affiliation(s)
- Andrea J. Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, California
| | | | - Alioune Badara Sy
- Centre de Recherche Biomédicale – Espoir Pour la Santé, Saint Louis, Sénégal
| | | | - Sofia Ali
- Stanford University, Stanford, California
| | | | - Sylvia Bereknyei Merrell
- Department of Surgery, Stanford Surgery Policy Improvement Research & Education Center (S-SPIRE), School of Medicine, Stanford University, Stanford, California
| | - Janine Bruce
- Pediatric Advocacy Program, Department of Pediatrics, School of Medicine, Stanford University, Stanford, California
| | - Nicolas Jouanard
- Centre de Recherche Biomédicale – Espoir Pour la Santé, Saint Louis, Sénégal
- Station d’Innovation Aquacole, Saint Louis, Senegal
| | - Simon Senghor
- Centre de Recherche Biomédicale – Espoir Pour la Santé, Saint Louis, Sénégal
| | - Gilles Riveau
- Centre de Recherche Biomédicale – Espoir Pour la Santé, Saint Louis, Sénégal
| | - David Lopez-Carr
- Department of Geography, University of California, Santa Barbara, Santa Barbara, California
| | - Giulio A. De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, California
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28
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Borremans B, Faust C, Manlove KR, Sokolow SH, Lloyd-Smith JO. Cross-species pathogen spillover across ecosystem boundaries: mechanisms and theory. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180344. [PMID: 31401953 PMCID: PMC6711298 DOI: 10.1098/rstb.2018.0344] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2019] [Indexed: 11/12/2022] Open
Abstract
Pathogen spillover between different host species is the trigger for many infectious disease outbreaks and emergence events, and ecosystem boundary areas have been suggested as spatial hotspots of spillover. This hypothesis is largely based on suspected higher rates of zoonotic disease spillover and emergence in fragmented landscapes and other areas where humans live in close vicinity to wildlife. For example, Ebola virus outbreaks have been linked to contacts between humans and infected wildlife at the rural-forest border, and spillover of yellow fever via mosquito vectors happens at the interface between forest and human settlements. Because spillover involves complex interactions between multiple species and is difficult to observe directly, empirical studies are scarce, particularly those that quantify underlying mechanisms. In this review, we identify and explore potential ecological mechanisms affecting spillover of pathogens (and parasites in general) at ecosystem boundaries. We borrow the concept of 'permeability' from animal movement ecology as a measure of the likelihood that hosts and parasites are present in an ecosystem boundary region. We then discuss how different mechanisms operating at the levels of organisms and ecosystems might affect permeability and spillover. This review is a step towards developing a general theory of cross-species parasite spillover across ecosystem boundaries with the eventual aim of improving predictions of spillover risk in heterogeneous landscapes. This article is part of the theme issue 'Dynamic and integrative approaches to understanding pathogen spillover'.
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Affiliation(s)
- Benny Borremans
- Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
- Interuniversity Institute for Biostatistics and Statistical Bioinformatics (I-BIOSTAT), Universiteit Hasselt, Hasselt, Limburg, Belgium
| | - Christina Faust
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
- Wellcome Centre for Molecular Parasitology, University of Glasgow, Glasgow, UK
| | - Kezia R. Manlove
- Department of Wildland Resources and Ecology Center, Utah State University, Logan, UT, USA
| | | | - James O. Lloyd-Smith
- Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
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29
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Sokolow SH, Nova N, Pepin KM, Peel AJ, Pulliam JRC, Manlove K, Cross PC, Becker DJ, Plowright RK, McCallum H, De Leo GA. Ecological interventions to prevent and manage zoonotic pathogen spillover. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180342. [PMID: 31401951 PMCID: PMC6711299 DOI: 10.1098/rstb.2018.0342] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Spillover of a pathogen from a wildlife reservoir into a human or livestock host requires the pathogen to overcome a hierarchical series of barriers. Interventions aimed at one or more of these barriers may be able to prevent the occurrence of spillover. Here, we demonstrate how interventions that target the ecological context in which spillover occurs (i.e. ecological interventions) can complement conventional approaches like vaccination, treatment, disinfection and chemical control. Accelerating spillover owing to environmental change requires effective, affordable, durable and scalable solutions that fully harness the complex processes involved in cross-species pathogen spillover. This article is part of the theme issue ‘Dynamic and integrative approaches to understanding pathogen spillover’.
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Affiliation(s)
- Susanne H Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA.,Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA.,Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - Nicole Nova
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Kim M Pepin
- National Wildlife Research Center, USDA-APHIS, Fort Collins, CO 80521, USA
| | - Alison J Peel
- Environmental Futures Research Institute, Griffith University, Nathan, Queensland 4111, Australia
| | - Juliet R C Pulliam
- South African DST-NRF Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), Stellenbosch University, Stellenbosch 7600, South Africa
| | - Kezia Manlove
- Department of Wildland Resources and Ecology Center, Utah State University, Logan, UT 84321, USA
| | - Paul C Cross
- US Geological Survey, Northern Rocky Mountain Science Center, Bozeman, MT 59715, USA
| | - Daniel J Becker
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA.,Department of Biology, Indiana University, Bloomington, IN 47403, USA
| | - Raina K Plowright
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Hamish McCallum
- Environmental Futures Research Institute, Griffith University, Nathan, Queensland 4111, Australia
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA.,Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA.,Department of Biology, Stanford University, Stanford, CA 94305, USA
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30
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Rohr JR, Barrett CB, Civitello DJ, Craft ME, Delius B, DeLeo GA, Hudson PJ, Jouanard N, Nguyen KH, Ostfeld RS, Remais JV, Riveau G, Sokolow SH, Tilman D. Emerging human infectious diseases and the links to global food production. Nat Sustain 2019; 2:445-456. [PMID: 32219187 PMCID: PMC7091874 DOI: 10.1038/s41893-019-0293-3] [Citation(s) in RCA: 211] [Impact Index Per Article: 42.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 04/17/2019] [Indexed: 05/07/2023]
Abstract
Infectious diseases are emerging globally at an unprecedented rate while global food demand is projected to increase sharply by 2100. Here, we synthesize the pathways by which projected agricultural expansion and intensification will influence human infectious diseases and how human infectious diseases might likewise affect food production and distribution. Feeding 11 billion people will require substantial increases in crop and animal production that will expand agricultural use of antibiotics, water, pesticides and fertilizer, and contact rates between humans and both wild and domestic animals, all with consequences for the emergence and spread of infectious agents. Indeed, our synthesis of the literature suggests that, since 1940, agricultural drivers were associated with >25% of all - and >50% of zoonotic - infectious diseases that emerged in humans, proportions that will likely increase as agriculture expands and intensifies. We identify agricultural and disease management and policy actions, and additional research, needed to address the public health challenge posed by feeding 11 billion people.
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Affiliation(s)
- Jason R. Rohr
- Department of Biological Sciences, Eck Institute for Global Health, and Environmental Change Initiative, University of Notre Dame, Notre Dame, IN USA
- Department of Integrative Biology, University of South Florida, Tampa, FL USA
| | | | | | - Meggan E. Craft
- Department of Veterinary Population Medicine, University of Minnesota, St Paul, MN USA
| | - Bryan Delius
- Department of Integrative Biology, University of South Florida, Tampa, FL USA
| | - Giulio A. DeLeo
- Department of Biology and Woods Institute for the Environment, Hopkins Marine Station, Stanford University, Pacific Grove, CA USA
| | - Peter J. Hudson
- Center for Infectious Disease Dynamics, Pennsylvania State University, College Station, PA USA
| | - Nicolas Jouanard
- Laboratoire de Recherches Biomédicales, Espoir pour la Santé, Saint-Louis, Senegal
| | - Karena H. Nguyen
- Department of Integrative Biology, University of South Florida, Tampa, FL USA
| | | | - Justin V. Remais
- Division of Environmental Health Sciences, University of California, Berkeley, Berkeley, CA USA
| | - Gilles Riveau
- Laboratoire de Recherches Biomédicales, Espoir pour la Santé, Saint-Louis, Senegal
| | - Susanne H. Sokolow
- Department of Biology and Woods Institute for the Environment, Hopkins Marine Station, Stanford University, Pacific Grove, CA USA
- Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA USA
| | - David Tilman
- Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, MN USA
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31
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Arostegui MC, Wood CL, Jones IJ, Chamberlin AJ, Jouanard N, Faye DS, Kuris AM, Riveau G, De Leo GA, Sokolow SH. Potential Biological Control of Schistosomiasis by Fishes in the Lower Senegal River Basin. Am J Trop Med Hyg 2019; 100:117-126. [PMID: 30479247 PMCID: PMC6335894 DOI: 10.4269/ajtmh.18-0469] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 09/26/2018] [Indexed: 12/19/2022] Open
Abstract
More than 200 million people in sub-Saharan Africa are infected with schistosome parasites. Transmission of schistosomiasis occurs when people come into contact with larval schistosomes emitted from freshwater snails in the aquatic environment. Thus, controlling snails through augmenting or restoring their natural enemies, such as native predators and competitors, could offer sustainable control for this human disease. Fishes may reduce schistosomiasis transmission directly, by preying on snails or parasites, or indirectly, by competing with snails for food or by reducing availability of macrophyte habitat (i.e., aquatic plants) where snails feed and reproduce. To identify fishes that might serve as native biological control agents for schistosomiasis in the lower Senegal River basin-one of the highest transmission areas for human schistosomiasis globally-we surveyed the freshwater fish that inhabit shallow, nearshore habitats and conducted multivariate analyses with quantitative diet data for each of the fish species encountered. Ten of the 16 fish species we encountered exhibited diets that may result in direct (predation) and/or indirect (food competition and habitat removal) control of snails. Fish abundance was low, suggesting limited effects on schistosomiasis transmission by the contemporary fish community in the lower Senegal River basin in the wild. Here, we highlight some native species-such as tilapia, West African lungfish, and freshwater prawns-that could be aquacultured for local-scale biological control of schistosomiasis transmission.
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Affiliation(s)
- Martin C. Arostegui
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington
| | - Chelsea L. Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington
| | - Isabel J. Jones
- Hopkins Marine Station of Stanford University, Pacific Grove, California
| | | | - Nicolas Jouanard
- Biomedical Research Center Espoir Pour La Santé, Saint-Louis, Sénégal
| | | | - Armand M. Kuris
- Department of Ecology, Evolution and Marine Biology, and Marine Science Institute, University of California, Santa Barbara, California
| | - Gilles Riveau
- Biomedical Research Center Espoir Pour La Santé, Saint-Louis, Sénégal
| | - Giulio A. De Leo
- Hopkins Marine Station of Stanford University, Pacific Grove, California
| | - Susanne H. Sokolow
- Hopkins Marine Station of Stanford University, Pacific Grove, California
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32
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Arakala A, Hoover CM, Marshall JM, Sokolow SH, De Leo GA, Rohr JR, Remais JV, Gambhir M. Estimating the elimination feasibility in the 'end game' of control efforts for parasites subjected to regular mass drug administration: Methods and their application to schistosomiasis. PLoS Negl Trop Dis 2018; 12:e0006794. [PMID: 30418968 PMCID: PMC6258430 DOI: 10.1371/journal.pntd.0006794] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/26/2018] [Accepted: 08/27/2018] [Indexed: 11/18/2022] Open
Abstract
Progress towards controlling and eliminating parasitic worms, including schistosomiasis, onchocerciasis, and lymphatic filariasis, is advancing rapidly as national governments, multinational NGOs, and pharmaceutical companies launch collaborative chemotherapeutic control campaigns. Critical questions remain regarding the potential for achieving elimination of these infections, and analytical methods can help to quickly estimate progress towards-and the probability of achieving-elimination over specific timeframes. Here, we propose the effective reproduction number, Reff, as a proxy of elimination potential for sexually reproducing worms that are subject to poor mating success at very low abundance (positive density dependence, or Allee effects). Reff is the number of parasites produced by a single reproductive parasite at a given stage in the transmission cycle, over the parasite's lifetime-it is the generalized form of the more familiar basic reproduction number, R0, which only applies at the beginning of an epidemic-and it can be estimated in a 'model-free' manner by an estimator ('ε'). We introduce ε, demonstrate its estimation using simulated data, and discuss how it may be used in planning and evaluation of ongoing elimination efforts for a range of parasitic diseases.
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Affiliation(s)
- Arathi Arakala
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia
| | - Christopher M. Hoover
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California, United States of America
| | - John M. Marshall
- Division of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, California, United States of America
| | - Susanne H. Sokolow
- Department of Biology—Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Giulio A. De Leo
- Department of Biology—Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Jason R. Rohr
- Department of Integrative Biology, University of Southern Florida, Tampa, Florida, United States of America
| | - Justin V. Remais
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California, United States of America
| | - Manoj Gambhir
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia
- Health Modelling and Analytics, IBM Research Australia, Melbourne, Australia
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33
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Halstead NT, Hoover CM, Arakala A, Civitello DJ, De Leo GA, Gambhir M, Johnson SA, Jouanard N, Loerns KA, McMahon TA, Ndione RA, Nguyen K, Raffel TR, Remais JV, Riveau G, Sokolow SH, Rohr JR. Agrochemicals increase risk of human schistosomiasis by supporting higher densities of intermediate hosts. Nat Commun 2018; 9:837. [PMID: 29483531 PMCID: PMC5826950 DOI: 10.1038/s41467-018-03189-w] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 01/26/2018] [Indexed: 11/09/2022] Open
Abstract
Schistosomiasis is a snail-borne parasitic disease that ranks among the most important water-based diseases of humans in developing countries. Increased prevalence and spread of human schistosomiasis to non-endemic areas has been consistently linked with water resource management related to agricultural expansion. However, the role of agrochemical pollution in human schistosome transmission remains unexplored, despite strong evidence of agrochemicals increasing snail-borne diseases of wildlife and a projected 2- to 5-fold increase in global agrochemical use by 2050. Using a field mesocosm experiment, we show that environmentally relevant concentrations of fertilizer, a herbicide, and an insecticide, individually and as mixtures, increase densities of schistosome-infected snails by increasing the algae snails eat and decreasing densities of snail predators. Epidemiological models indicate that these agrochemical effects can increase transmission of schistosomes. Identifying agricultural practices or agrochemicals that minimize disease risk will be critical to meeting growing food demands while improving human wellbeing.
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Affiliation(s)
- Neal T Halstead
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA.
- Wildlands Conservation, Inc., 15310 Amberly Drive, Suite 250, Tampa, FL, 33647, USA.
| | - Christopher M Hoover
- Division of Environmental Health Sciences, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Arathi Arakala
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, 3800,, Australia
- Department of Mathematical Sciences, RMIT University, GPO Box 2476, Melbourne, 3001, Australia
| | | | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, 93950, USA
- Stanford Woods Institute for the Environment, Stanford University, Stanford, CA, 94305, USA
| | - Manoj Gambhir
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, 3800,, Australia
- IBM Research Australia, Global Services Australia Pvt. Ltd., 60 City Road, Southbank, 3006, Australia
| | - Steve A Johnson
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, 32611, USA
| | - Nicolas Jouanard
- Centre de Recherche Biomédicale Espoir pour la Santé, BP 226, Saint-Louis, Senegal
| | - Kristin A Loerns
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
| | - Taegan A McMahon
- Department of Biology, University of Tampa, Tampa, FL, 33606, USA
| | - Raphael A Ndione
- Centre de Recherche Biomédicale Espoir pour la Santé, BP 226, Saint-Louis, Senegal
| | - Karena Nguyen
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
| | - Thomas R Raffel
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA
| | - Justin V Remais
- Division of Environmental Health Sciences, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Gilles Riveau
- Centre de Recherche Biomédicale Espoir pour la Santé, BP 226, Saint-Louis, Senegal
- CIIL - Institut Pasteur de Lille, 1 Rue du Professeur Calmette, 59019, Lille, France
| | - Susanne H Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, 93950, USA
- Stanford Woods Institute for the Environment, Stanford University, Stanford, CA, 94305, USA
| | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
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Sokolow SH, Jones IJ, Jocque M, La D, Cords O, Knight A, Lund A, Wood CL, Lafferty KD, Hoover CM, Collender PA, Remais JV, Lopez-Carr D, Fisk J, Kuris AM, De Leo GA. Nearly 400 million people are at higher risk of schistosomiasis because dams block the migration of snail-eating river prawns. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0127. [PMID: 28438916 PMCID: PMC5413875 DOI: 10.1098/rstb.2016.0127] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2016] [Indexed: 11/21/2022] Open
Abstract
Dams have long been associated with elevated burdens of human schistosomiasis, but how dams increase disease is not always clear, in part because dams have many ecological and socio-economic effects. A recent hypothesis argues that dams block reproduction of the migratory river prawns that eat the snail hosts of schistosomiasis. In the Senegal River Basin, there is evidence that prawn populations declined and schistosomiasis increased after completion of the Diama Dam. Restoring prawns to a water-access site upstream of the dam reduced snail density and reinfection rates in people. However, whether a similar cascade of effects (from dams to prawns to snails to human schistosomiasis) occurs elsewhere is unknown. Here, we examine large dams worldwide and identify where their catchments intersect with endemic schistosomiasis and the historical habitat ranges of large, migratory Macrobrachium spp. prawns. River prawn habitats are widespread, and we estimate that 277–385 million people live within schistosomiasis-endemic regions where river prawns are or were present (out of the 800 million people who are at risk of schistosomiasis). Using a published repository of schistosomiasis studies in sub-Saharan Africa, we compared infection before and after the construction of 14 large dams for people living in: (i) upstream catchments within historical habitats of native prawns, (ii) comparable undammed watersheds, and (iii) dammed catchments beyond the historical reach of migratory prawns. Damming was followed by greater increases in schistosomiasis within prawn habitats than outside prawn habitats. We estimate that one third to one half of the global population-at-risk of schistosomiasis could benefit from restoration of native prawns. Because dams block prawn migrations, our results suggest that prawn extirpation contributes to the sharp increase of schistosomiasis after damming, and points to prawn restoration as an ecological solution for reducing human disease. This article is part of the themed issue ‘Conservation, biodiversity and infectious disease: scientific evidence and policy implications’.
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Affiliation(s)
- Susanne H Sokolow
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA .,Marine Science Institute, and Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA
| | - Isabel J Jones
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Merlijn Jocque
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Diana La
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Olivia Cords
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Anika Knight
- Department of Biology, Medaille College, Buffalo, NY 14214, USA.,Department of Veterinary Technology, Medaille College, Buffalo, NY 14214, USA
| | - Andrea Lund
- Emmett Interdisciplinary Program in Environmental Resources, School of Earth, Energy, and Environmental Sciences, Stanford University, Stanford, CA 94305, USA
| | - Chelsea L Wood
- Department of Ecology and Evolutionary Biology and Michigan Society of Fellows, University of Michigan, Ann Arbor, MI 48109, USA.,School of Aquatic and Fishery Science, University of Washington, Seattle, WA 98195, USA
| | - Kevin D Lafferty
- Marine Science Institute, and Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA.,Western Ecological Research Center, U.S. Geological Survey, Santa Barbara, CA 93106, USA
| | - Christopher M Hoover
- Division of Environmental Health Sciences, School of Public Health, University of California Berkeley, Berkeley, CA 94720, USA
| | - Phillip A Collender
- Division of Environmental Health Sciences, School of Public Health, University of California Berkeley, Berkeley, CA 94720, USA
| | - Justin V Remais
- Division of Environmental Health Sciences, School of Public Health, University of California Berkeley, Berkeley, CA 94720, USA
| | - David Lopez-Carr
- Department of Geography, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Jonathan Fisk
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Armand M Kuris
- Marine Science Institute, and Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA
| | - Giulio A De Leo
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
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35
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Sokolow SH, Wood CL, Jones IJ, Lafferty KD, Kuris AM, Hsieh MH, De Leo GA. To Reduce the Global Burden of Human Schistosomiasis, Use 'Old Fashioned' Snail Control. Trends Parasitol 2018; 34:23-40. [PMID: 29126819 PMCID: PMC5819334 DOI: 10.1016/j.pt.2017.10.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/30/2017] [Accepted: 10/16/2017] [Indexed: 12/27/2022]
Abstract
Control strategies to reduce human schistosomiasis have evolved from 'snail picking' campaigns, a century ago, to modern wide-scale human treatment campaigns, or preventive chemotherapy. Unfortunately, despite the rise in preventive chemotherapy campaigns, just as many people suffer from schistosomiasis today as they did 50 years ago. Snail control can complement preventive chemotherapy by reducing the risk of transmission from snails to humans. Here, we present ideas for modernizing and scaling up snail control, including spatiotemporal targeting, environmental diagnostics, better molluscicides, new technologies (e.g., gene drive), and 'outside the box' strategies such as natural enemies, traps, and repellants. We conclude that, to achieve the World Health Assembly's stated goal to eliminate schistosomiasis, it is time to give snail control another look.
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Affiliation(s)
- Susanne H Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA; Marine Science Institute, University of California, Santa Barbara, CA 93106, USA.
| | - Chelsea L Wood
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98195-5020, USA
| | - Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Kevin D Lafferty
- U.S. Geological Survey, Western Ecological Research Center, c/o Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - Armand M Kuris
- Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - Michael H Hsieh
- Children's National Health System, Washington DC, 20010, USA; The George Washington University, Washington DC, 20037, USA; Biomedical Research Institute, Rockville, MD 20850, USA
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
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Ciddio M, Mari L, Sokolow SH, De Leo GA, Casagrandi R, Gatto M. The spatial spread of schistosomiasis: A multidimensional network model applied to Saint-Louis region, Senegal. Adv Water Resour 2017; 108:406-415. [PMID: 29056816 PMCID: PMC5637889 DOI: 10.1016/j.advwatres.2016.10.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 09/13/2016] [Accepted: 10/10/2016] [Indexed: 05/06/2023]
Abstract
Schistosomiasis is a parasitic, water-related disease that is prevalent in tropical and subtropical areas of the world, causing severe and chronic consequences especially among children. Here we study the spatial spread of this disease within a network of connected villages in the endemic region of the Lower Basin of the Senegal River, in Senegal. The analysis is performed by means of a spatially explicit metapopulation model that couples local-scale eco-epidemiological dynamics with spatial mechanisms related to human mobility (estimated from anonymized mobile phone records), snail dispersal and hydrological transport of schistosome larvae along the main water bodies of the region. Results show that the model produces epidemiological patterns consistent with field observations, and point out the key role of spatial connectivity on the spread of the disease. These findings underline the importance of considering different transport pathways in order to elaborate disease control strategies that can be effective within a network of connected populations.
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Affiliation(s)
- Manuela Ciddio
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
| | - Lorenzo Mari
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
| | - Susanne H. Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, United States
- Marine Science Institute, University of California, Santa Barbara, CA 93106, United States
| | - Giulio A. De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, United States
| | - Renato Casagrandi
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
| | - Marino Gatto
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
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37
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Mari L, Ciddio M, Casagrandi R, Perez-Saez J, Bertuzzo E, Rinaldo A, Sokolow SH, De Leo GA, Gatto M. Heterogeneity in schistosomiasis transmission dynamics. J Theor Biol 2017; 432:87-99. [PMID: 28823529 PMCID: PMC5595357 DOI: 10.1016/j.jtbi.2017.08.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/30/2017] [Accepted: 08/15/2017] [Indexed: 01/30/2023]
Abstract
Transmission dynamics of schistosomiasis presents multiple heterogeneity sources. A comprehensive framework for heterogeneous disease transmission is proposed. Heterogeneous multigroup communities can be more prone to parasite transmission. Presence of multiple water sources can hinder parasite transmission. Spatial and temporal heterogeneities can have nontrivial implications for endemicity.
Simple models of disease propagation often disregard the effects of transmission heterogeneity on the ecological and epidemiological dynamics associated with host-parasite interactions. However, for some diseases like schistosomiasis, a widespread parasitic infection caused by Schistosoma worms, accounting for heterogeneity is crucial to both characterize long-term dynamics and evaluate opportunities for disease control. Elaborating on the classic Macdonald model for macroparasite transmission, we analyze families of models including explicit descriptions of heterogeneity related to differential transmission risk within a community, water contact patterns, the distribution of the snail host population, human mobility, and the seasonal fluctuations of the environment. Through simple numerical examples, we show that heterogeneous multigroup communities may be more prone to schistosomiasis than homogeneous ones, that the availability of multiple water sources can hinder parasite transmission, and that both spatial and temporal heterogeneities may have nontrivial implications for disease endemicity. Finally, we discuss the implications of heterogeneity for disease control. Although focused on schistosomiasis, results from this study may apply as well to other parasitic infections with complex transmission cycles, such as cysticercosis, dracunculiasis and fasciolosis.
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Affiliation(s)
- Lorenzo Mari
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy.
| | - Manuela Ciddio
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
| | - Renato Casagrandi
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
| | - Javier Perez-Saez
- Laboratory of Ecohydrology, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Enrico Bertuzzo
- Dipartimento di Scienze Ambientali, Informatica e Statistica, Università Ca' Foscari Venezia, 30170 Venezia Mestre, Italy
| | - Andrea Rinaldo
- Laboratory of Ecohydrology, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Dipartimento ICEA, Università di Padova, 35131 Padova, Italy
| | - Susanne H Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA; Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Marino Gatto
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
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Garchitorena A, Sokolow SH, Roche B, Ngonghala CN, Jocque M, Lund A, Barry M, Mordecai EA, Daily GC, Jones JH, Andrews JR, Bendavid E, Luby SP, LaBeaud AD, Seetah K, Guégan JF, Bonds MH, De Leo GA. Disease ecology, health and the environment: a framework to account for ecological and socio-economic drivers in the control of neglected tropical diseases. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160128. [PMID: 28438917 PMCID: PMC5413876 DOI: 10.1098/rstb.2016.0128] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2017] [Indexed: 01/27/2023] Open
Abstract
Reducing the burden of neglected tropical diseases (NTDs) is one of the key strategic targets advanced by the Sustainable Development Goals. Despite the unprecedented effort deployed for NTD elimination in the past decade, their control, mainly through drug administration, remains particularly challenging: persistent poverty and repeated exposure to pathogens embedded in the environment limit the efficacy of strategies focused exclusively on human treatment or medical care. Here, we present a simple modelling framework to illustrate the relative role of ecological and socio-economic drivers of environmentally transmitted parasites and pathogens. Through the analysis of system dynamics, we show that periodic drug treatments that lead to the elimination of directly transmitted diseases may fail to do so in the case of human pathogens with an environmental reservoir. Control of environmentally transmitted diseases can be more effective when human treatment is complemented with interventions targeting the environmental reservoir of the pathogen. We present mechanisms through which the environment can influence the dynamics of poverty via disease feedbacks. For illustration, we present the case studies of Buruli ulcer and schistosomiasis, two devastating waterborne NTDs for which control is particularly challenging.This article is part of the themed issue 'Conservation, biodiversity and infectious disease: scientific evidence and policy implications'.
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Affiliation(s)
- A Garchitorena
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA 02115, USA
- PIVOT, Division of Global Health Equity, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - S H Sokolow
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - B Roche
- UMI UMMISCO 209 IRD/UPMC - Bondy, France
- UMR MIVEGEC 5290 CNRS - IRD - Université de Montpellier, Montpellier, France
| | - C N Ngonghala
- Department of Mathematics, University of Florida, Gainesville, FL 32611, USA
| | - M Jocque
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - A Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, CA 94305, USA
| | - M Barry
- Center for Innovation in Global Health, Stanford University, Stanford, CA 94305, USA
| | - E A Mordecai
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - G C Daily
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - J H Jones
- Department of Earth System Science, Stanford University, Stanford, CA 94305, USA
- Department of Life Sciences, Imperial College, London, UK
| | - J R Andrews
- Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - E Bendavid
- Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - S P Luby
- Center for Innovation in Global Health, Stanford University, Stanford, CA 94305, USA
| | - A D LaBeaud
- Department of Pediatrics, Division of Infectious Diseases, Stanford University, Stanford, CA 94305, USA
| | - K Seetah
- Department of Anthropology, Stanford University, Stanford, CA 94305, USA
| | - J F Guégan
- UMR MIVEGEC 5290 CNRS - IRD - Université de Montpellier, Montpellier, France
- Future Earth international programme, OneHealth core research programme, Montréal, Canada
| | - M H Bonds
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA 02115, USA
- PIVOT, Division of Global Health Equity, Brigham and Women's Hospital, Boston, MA 02115, USA
- Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - G A De Leo
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
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Swartz SJ, De Leo GA, Wood CL, Sokolow SH. Infection with schistosome parasites in snails leads to increased predation by prawns: implications for human schistosomiasis control. ACTA ACUST UNITED AC 2017; 218:3962-7. [PMID: 26677260 DOI: 10.1242/jeb.129221] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Schistosomiasis - a parasitic disease that affects over 200 million people across the globe - is primarily transmitted between human definitive hosts and snail intermediate hosts. To reduce schistosomiasis transmission, some have advocated disrupting the schistosome life cycle through biological control of snails, achieved by boosting the abundance of snails' natural predators. But little is known about the effect of parasitic infection on predator-prey interactions, especially in the case of schistosomiasis. Here, we present the results of laboratory experiments performed on Bulinus truncatus and Biomphalaria glabrata snails to investigate: (i) rates of predation on schistosome-infected versus uninfected snails by a sympatric native river prawn, Macrobrachium vollenhovenii, and (ii) differences in snail behavior (including movement, refuge-seeking and anti-predator behavior) between infected and uninfected snails. In predation trials, prawns showed a preference for consuming snails infected with schistosome larvae. In behavioral trials, infected snails moved less quickly and less often than uninfected snails, and were less likely to avoid predation by exiting the water or hiding under substrate. Although the mechanism by which the parasite alters snail behavior remains unknown, these results provide insight into the effects of parasitic infection on predator-prey dynamics and suggest that boosting natural rates of predation on snails may be a useful strategy for reducing transmission in schistosomiasis hotspots.
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Affiliation(s)
- Scott J Swartz
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Giulio A De Leo
- Department of Biology, Stanford University, Stanford, CA 94305, USA Hopkins Marine Station of Stanford University, Pacific Grove, CA 93950, USA
| | - Chelsea L Wood
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA Michigan Society of Fellows, University of Michigan, Ann Arbor, MI 48109, USA
| | - Susanne H Sokolow
- Hopkins Marine Station of Stanford University, Pacific Grove, CA 93950, USA Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
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40
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Sokolow SH, Wood CL, Jones IJ, Swartz SJ, Lopez M, Hsieh MH, Lafferty KD, Kuris AM, Rickards C, De Leo GA. Global Assessment of Schistosomiasis Control Over the Past Century Shows Targeting the Snail Intermediate Host Works Best. PLoS Negl Trop Dis 2016; 10:e0004794. [PMID: 27441556 PMCID: PMC4956325 DOI: 10.1371/journal.pntd.0004794] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 05/31/2016] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Despite control efforts, human schistosomiasis remains prevalent throughout Africa, Asia, and South America. The global schistosomiasis burden has changed little since the new anthelmintic drug, praziquantel, promised widespread control. METHODOLOGY We evaluated large-scale schistosomiasis control attempts over the past century and across the globe by identifying factors that predict control program success: snail control (e.g., molluscicides or biological control), mass drug administrations (MDA) with praziquantel, or a combined strategy using both. For data, we compiled historical information on control tactics and their quantitative outcomes for all 83 countries and territories in which: (i) schistosomiasis was allegedly endemic during the 20th century, and (ii) schistosomiasis remains endemic, or (iii) schistosomiasis has been "eliminated," or is "no longer endemic," or transmission has been interrupted. PRINCIPAL FINDINGS Widespread snail control reduced prevalence by 92 ± 5% (N = 19) vs. 37 ± 7% (N = 29) for programs using little or no snail control. In addition, ecological, economic, and political factors contributed to schistosomiasis elimination. For instance, snail control was most common and widespread in wealthier countries and when control began earlier in the 20th century. CONCLUSIONS/SIGNIFICANCE Snail control has been the most effective way to reduce schistosomiasis prevalence. Despite evidence that snail control leads to long-term disease reduction and elimination, most current schistosomiasis control efforts emphasize MDA using praziquantel over snail control. Combining drug-based control programs with affordable snail control seems the best strategy for eliminating schistosomiasis.
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Affiliation(s)
- Susanne H. Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
- Marine Science Institute, and Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, United States of America
- * E-mail:
| | - Chelsea L. Wood
- Michigan Society of Fellows, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Isabel J. Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Scott J. Swartz
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Melina Lopez
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Michael H. Hsieh
- Children's National Health System, Washington, D.C., United States of America
- The George Washington University, Washington, D.C., United States of America
- Biomedical Research Institute, Rockville, Maryland, United States of America
| | - Kevin D. Lafferty
- Marine Science Institute, and Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, United States of America
- Western Ecological Research Center, U.S. Geological Survey, Santa Barbara, California, United States of America
| | - Armand M. Kuris
- Marine Science Institute, and Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, United States of America
| | - Chloe Rickards
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Giulio A. De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
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Perez-Saez J, Mari L, Bertuzzo E, Casagrandi R, Sokolow SH, De Leo GA, Mande T, Ceperley N, Froehlich JM, Sou M, Karambiri H, Yacouba H, Maiga A, Gatto M, Rinaldo A. A Theoretical Analysis of the Geography of Schistosomiasis in Burkina Faso Highlights the Roles of Human Mobility and Water Resources Development in Disease Transmission. PLoS Negl Trop Dis 2015; 9:e0004127. [PMID: 26513655 PMCID: PMC4625963 DOI: 10.1371/journal.pntd.0004127] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/08/2015] [Indexed: 12/28/2022] Open
Abstract
We study the geography of schistosomiasis across Burkina Faso by means of a spatially explicit model of water-based disease dynamics. The model quantitatively addresses the geographic stratification of disease burden in a novel framework by explicitly accounting for drivers and controls of the disease, including spatial information on the distributions of population and infrastructure, jointly with a general description of human mobility and climatic/ecological drivers. Spatial patterns of disease are analysed by the extraction and the mapping of suitable eigenvectors of the Jacobian matrix subsuming the stability of the disease-free equilibrium. The relevance of the work lies in the novel mapping of disease burden, a byproduct of the parametrization induced by regional upscaling, by model-guided field validations and in the predictive scenarios allowed by exploiting the range of possible parameters and processes. Human mobility is found to be a primary control at regional scales both for pathogen invasion success and the overall distribution of disease burden. The effects of water resources development highlighted by systematic reviews are accounted for by the average distances of human settlements from water bodies that are habitats for the parasite’s intermediate host. Our results confirm the empirical findings about the role of water resources development on disease spread into regions previously nearly disease-free also by inspection of empirical prevalence patterns. We conclude that while the model still needs refinements based on field and epidemiological evidence, the proposed framework provides a powerful tool for large-scale public health planning and schistosomiasis management. Dynamical models of schistosomiasis infections, even spatially explicit ones, have so far only addressed spatial scales encompassing at best a few villages and the disease transmission impacts of related short-range human mobility. Here, we build from existing models of disease dynamics and spread, including a proxy of the ecology of the intermediate host of the parasite, and from generalized reproduction numbers of SIR-type systems developed for epidemics of waterborne disease, to set up large-scale projections of spatial patterns of the disease at whole country level. We ground our study in Burkina Faso in sub-Saharan Africa, and its model of social and economic development including the infrastructure built to exploit water resources, especially irrigation schemes, which have been empirically linked to enhanced disease burden. We make extensive use of remotely sensed and field data, and capitalize on ecohydrological insight. We suggest that reliable nationwide patterns of disease burden can be projected in relation to the key roles of human mobility and water resources development subsuming exposure, and claim that the case at hand provides an insightful example towards the integration of development and environmental thinking not confined to ad-hoc indicators of human development.
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Affiliation(s)
- Javier Perez-Saez
- Laboratory of Ecohydrology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Lorenzo Mari
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
| | - Enrico Bertuzzo
- Laboratory of Ecohydrology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Renato Casagrandi
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
| | - Susanne H. Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
- Marine Science Institute, University of California Santa Barbara, California, United States of America
| | - Giulio A. De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
- Woods Institute for the Environment, Stanford University, California, United States of America
| | - Theophile Mande
- Laboratory of Ecohydrology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Natalie Ceperley
- Laboratory of Ecohydrology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jean-Marc Froehlich
- Laboratory of Ecohydrology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Mariam Sou
- Institute International d’Ingénierie de l’Eau et de l’Environment, Ouagadougou, Burkina Faso
| | - Harouna Karambiri
- Institute International d’Ingénierie de l’Eau et de l’Environment, Ouagadougou, Burkina Faso
| | - Hamma Yacouba
- Institute International d’Ingénierie de l’Eau et de l’Environment, Ouagadougou, Burkina Faso
| | - Amadou Maiga
- Institute International d’Ingénierie de l’Eau et de l’Environment, Ouagadougou, Burkina Faso
| | - Marino Gatto
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
| | - Andrea Rinaldo
- Laboratory of Ecohydrology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Dipartimento ICEA, Università di Padova, Padova, Italy
- * E-mail:
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Savaya Alkalay A, Rosen O, Sokolow SH, Faye YPW, Faye DS, Aflalo ED, Jouanard N, Zilberg D, Huttinger E, Sagi A. The prawn Macrobrachium vollenhovenii in the Senegal River basin: towards sustainable restocking of all-male populations for biological control of schistosomiasis. PLoS Negl Trop Dis 2014; 8:e3060. [PMID: 25166746 PMCID: PMC4148216 DOI: 10.1371/journal.pntd.0003060] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 06/18/2014] [Indexed: 02/04/2023] Open
Abstract
Early malacological literature suggests that the outbreak of schistosomiasis, a parasitic disease transmitted by aquatic snails, in the Senegal River basin occurred due to ecological changes resulting from the construction of the Diama dam. The common treatment, the drug praziquantel, does not protect from the high risk of re-infection due to human contact with infested water on a daily basis. The construction of the dam interfered with the life cycle of the prawn Macrobrachium vollenhovenii by blocking its access to breeding grounds in the estuary. These prawns were demonstrated to be potential biological control agents, being effective predators of Schistosoma-susceptible snails. Here, we propose a responsible restocking strategy using all-male prawn populations which could provide sustainable disease control. Male prawns reach a larger size and have a lower tendency to migrate than females. We, therefore, expect that periodic restocking of all-male juveniles will decrease the prevalence of schistosomiasis and increase villagers' welfare. In this interdisciplinary study, we examined current prawn abundance along the river basin, complemented with a retrospective questionnaire completed by local fishermen. We revealed the current absence of prawns upriver and thus demonstrated the need for restocking. Since male prawns are suggested to be preferable for bio-control, we laid the molecular foundation for production of all-male M. vollenhovenii through a complete sequencing of the insulin-like androgenic gland-encoding gene (IAG), which is responsible for sexual differentiation in crustaceans. We also conducted bioinformatics and immunohistochemistry analyses to demonstrate the similarity of this sequence to the IAG of another Macrobrachium species in which neo-females are produced and their progeny are 100% males. At least 100 million people at risk of schistosomiasis are residents of areas that experienced water management manipulations. Our suggested non-breeding sustainable model of control—if proven successful—could prevent re-infections and thus prove useful throughout the world. Schistosomiasis is a chronic parasitic disease that infects millions of people, especially in Africa. Schistosomes are transmitted by direct contact with water sources infested by freshwater snails, which are intermediate hosts for the parasite. The cure in humans is a drug, praziquantel, that kills the mature parasites inside the human body. The main problem with controlling the parasite by drug treatment is the high re-infection rate, since individuals are in contact with infected water on a daily basis. To efficiently combat the disease, an integrated management program is needed that includes control of infection in the intermediate host snails. We suggest the use of non-migrating, all-male populations of freshwater prawns that efficiently prey on these snails. Here, we describe the case of the Senegal River basin as an example of human actions (dam construction) that resulted in severe ecosystem changes, including exclusion of the native river prawns and expansion of snails hosting schistosomiasis. We have conducted an interdisciplinary study that documents the reduction of prawn abundance in the Senegal River and lays the molecular foundation for technology to produce all-male prawn populations to be used as part of an integrated disease control program, including both periodic stocking of juvenile prawns and chemotherapy.
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Affiliation(s)
- Amit Savaya Alkalay
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University, Beer Sheva, Israel
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institute for Desert Research, Ben-Gurion University, Sede-Boqer, Israel
| | - Ohad Rosen
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University, Beer Sheva, Israel
| | - Susanne H. Sokolow
- Department of Biology, Hopkins Marine Station, Stanford University, Palo Alto, California, United States of America
| | | | | | - Eliahu D. Aflalo
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University, Beer Sheva, Israel
| | - Nicolas Jouanard
- Centre de Recherche Biomédicale Espoir Pour La Santé, Sor, Saint-Louis, Senegal
| | - Dina Zilberg
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institute for Desert Research, Ben-Gurion University, Sede-Boqer, Israel
| | | | - Amir Sagi
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University, Beer Sheva, Israel
- * E-mail:
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Kuris AM, Lafferty KD, Sokolow SH. Sapronosis: a distinctive type of infectious agent. Trends Parasitol 2014; 30:386-93. [PMID: 25028088 DOI: 10.1016/j.pt.2014.06.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 06/18/2014] [Accepted: 06/18/2014] [Indexed: 11/18/2022]
Abstract
Sapronotic disease agents have evolutionary and epidemiological properties unlike other infectious organisms. Their essential saprophagic existence prevents coevolution, and no host-parasite virulence trade-off can evolve. However, the host may evolve defenses. Models of pathogens show that sapronoses, lacking a threshold of transmission, cannot regulate host populations, although they can reduce host abundance and even extirpate their hosts. Immunocompromised hosts are relatively susceptible to sapronoses. Some particularly important sapronoses, such as cholera and anthrax, can sustain an epidemic in a host population. However, these microbes ultimately persist as saprophages. One-third of human infectious disease agents are sapronotic, including nearly all fungal diseases. Recognition that an infectious disease is sapronotic illuminates a need for effective environmental control strategies.
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Affiliation(s)
- Armand M Kuris
- Department of Ecology, Evolution, and Marine Biology and Marine Science Institute, University of California, Santa Barbara, CA 93106, USA.
| | - Kevin D Lafferty
- Western Ecological Research Center, US Geological Survey c/o Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - Susanne H Sokolow
- Marine Science Institute, University of California, Santa Barbara, CA 93106, USA; Hopkins Marine Station, Stanford University, Pacific Grove, CA, 93950, USA
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Sokolow SH, Lafferty KD, Kuris AM. Regulation of laboratory populations of snails (Biomphalaria and Bulinus spp.) by river prawns, Macrobrachium spp. (Decapoda, Palaemonidae): implications for control of schistosomiasis. Acta Trop 2014; 132:64-74. [PMID: 24388955 PMCID: PMC4280914 DOI: 10.1016/j.actatropica.2013.12.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/13/2013] [Accepted: 12/19/2013] [Indexed: 10/25/2022]
Abstract
Human schistosomiasis is a common parasitic disease endemic in many tropical and subtropical countries. One barrier to achieving long-term control of this disease has been re-infection of treated patients when they swim, bathe, or wade in surface fresh water infested with snails that harbor and release larval parasites. Because some snail species are obligate intermediate hosts of schistosome parasites, removing snails may reduce parasitic larvae in the water, reducing re-infection risk. Here, we evaluate the potential for snail control by predatory freshwater prawns, Macrobrachium rosenbergii and M. vollenhovenii, native to Asia and Africa, respectively. Both prawn species are high value, protein-rich human food commodities, suggesting their cultivation may be beneficial in resource-poor settings where few other disease control options exist. In a series of predation trials in laboratory aquaria, we found both species to be voracious predators of schistosome-susceptible snails, hatchlings, and eggs, even in the presence of alternative food, with sustained average consumption rates of 12% of their body weight per day. Prawns showed a weak preference for Bulinus truncatus over Biomphalaria glabrata snails. Consumption rates were highly predictable based on the ratio of prawn: snail body mass, suggesting satiation-limited predation. Even the smallest prawns tested (0.5-2g) caused snail recruitment failure, despite high snail fecundity. With the World Health Organization turning attention toward schistosomiasis elimination, native prawn cultivation may be a viable snail control strategy that offers a win-win for public health and economic development.
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Affiliation(s)
- Susanne H Sokolow
- Ecology Evolution and Marine Biology Department, University of California Santa Barbara, Santa Barbara, CA, 93106, USA.
| | - Kevin D Lafferty
- Western Ecological Research Center, US Geological Survey, c/o Marine Science Institute, University of California, Santa Barbara, CA, 93106, USA
| | - Armand M Kuris
- Ecology Evolution and Marine Biology Department, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
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Hosseini P, Sokolow SH, Vandegrift KJ, Kilpatrick AM, Daszak P. Predictive power of air travel and socio-economic data for early pandemic spread. PLoS One 2010; 5:e12763. [PMID: 20856678 PMCID: PMC2939898 DOI: 10.1371/journal.pone.0012763] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Accepted: 05/24/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Controlling the pandemic spread of newly emerging diseases requires rapid, targeted allocation of limited resources among nations. Critical, early control steps would be greatly enhanced if the key risk factors can be identified that accurately predict early disease spread immediately after emergence. METHODOLOGY/PRINCIPAL FINDINGS Here, we examine the role of travel, trade, and national healthcare resources in predicting the emergence and initial spread of 2009 A/H1N1 influenza. We find that incorporating national healthcare resource data into our analyses allowed a much greater capacity to predict the international spread of this virus. In countries with lower healthcare resources, the reporting of 2009 A/H1N1 cases was significantly delayed, likely reflecting a lower capacity for testing and reporting, as well as other socio-political issues. We also report substantial international trade in live swine and poultry in the decade preceding the pandemic which may have contributed to the emergence and mixed genotype of this pandemic strain. However, the lack of knowledge of recent evolution of each H1N1 viral gene segment precludes the use of this approach to determine viral origins. CONCLUSIONS/SIGNIFICANCE We conclude that strategies to prevent pandemic influenza virus emergence and spread in the future should include: 1) enhanced surveillance for strains resulting from reassortment in traded livestock; 2) rapid deployment of control measures in the initial spreading phase to countries where travel data predict the pathogen will reach and to countries where lower healthcare resources will likely cause delays in reporting. Our results highlight the benefits, for all parties, when higher income countries provide additional healthcare resources for lower income countries, particularly those that have high air traffic volumes. In particular, international authorities should prioritize aid to those poorest countries where both the risk of emerging infectious diseases and air traffic volume is highest. This strategy will result in earlier detection of pathogens and a reduction in the impact of future pandemics.
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Affiliation(s)
- Parviez Hosseini
- EcoHealth Alliance (formerly Wildlife Trust), New York, New York, United States of America
| | - Susanne H. Sokolow
- University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Kurt J. Vandegrift
- EcoHealth Alliance (formerly Wildlife Trust), New York, New York, United States of America
| | - A. Marm Kilpatrick
- University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Peter Daszak
- EcoHealth Alliance (formerly Wildlife Trust), New York, New York, United States of America
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Abstract
Influenza A virus infections result in approximately 500,000 human deaths per year and many more sublethal infections. Wild birds are recognized as the ancestral host of influenza A viruses, and avian viruses have contributed genetic material to most human viruses, including subtypes H5N1 and H1N1. Thus, influenza virus transmission in wild and domestic animals and humans is intimately connected. Here we review how anthropogenic change, including human population growth, land use, climate change, globalization of trade, agricultural intensification, and changes in vaccine technology may alter the evolution and transmission of influenza viruses. Evidence suggests that viral transmission in domestic poultry, spillover to other domestic animals, wild birds and humans, and the potential for subsequent pandemic spread, are all increasing. We highlight four areas in need of research: drivers of viral subtype dynamics; ecological and evolutionary determinants of transmissibility and virulence in birds and humans; the impact of changing land use and climate on hosts, viruses, and transmission; and the impact of influenza viruses on wild bird hosts, including their ability to migrate while shedding virus.
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Affiliation(s)
| | - Susanne H. Sokolow
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA
| | | | - A. Marm Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA
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Sokolow SH, Foley P, Foley JE, Hastings A, Richardson LL. Editor's choice: Disease dynamics in marine metapopulations: modelling infectious diseases on coral reefs. J Appl Ecol 2009. [DOI: 10.1111/j.1365-2664.2009.01649.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
OBJECTIVES To determine associations among infectious pathogens and diarrheal disease in dogs in an animal shelter and demonstrate the use of geographic information systems (GISs) for tracking spatial distributions of diarrheal disease within shelters. SAMPLE POPULATION Feces from 120 dogs. PROCEDURE Fresh fecal specimens were screened for bacteria and bacterial toxins via bacteriologic culture and ELISA, parvovirus via ELISA, canine coronavirus via nested polymerase chain reaction assay, protozoal cysts and oocysts via a direct fluorescent antibody technique, and parasite ova and larvae via microscopic examination of direct wet mounts and zinc sulfate centrifugation flotation. RESULTS Salmonella enterica and Brachyspira spp were not common, whereas other pathogens such as canine coronavirus and Helicobacter spp were common among the dogs that were surveyed. Only intestinal parasites and Campylobacterjejuni infection were significant risk factors for diarrhea by univariate odds ratio analysis. Giardia lamblia was significantly underestimated by fecal flotation, compared with a direct fluorescent antibody technique. Spatial analysis of case specimens by use of GIS indicated that diarrhea was widespread throughout the entire shelter, and spatial statistical analysis revealed no evidence of spatial clustering of case specimens. CONCLUSIONS AND CLINICAL RELEVANCE This study provided an epidemiologic overview of diarrhea and interacting diarrhea-associated pathogens in a densely housed, highly predisposed shelter population of dogs. Several of the approaches used in this study, such as use of a spatial representation of case specimens and considering multiple etiologies simultaneously, were novel and illustrate an integrated approach to epidemiologic investigations in shelter populations.
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Affiliation(s)
- Susanne H Sokolow
- Center for Companion Animal Health, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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