1
|
Manley W, Tran T, Prusinski M, Brisson D. Modeling Tick Populations: An Ecological Test Case for Gradient Boosted Trees. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.13.532443. [PMID: 36993623 PMCID: PMC10054924 DOI: 10.1101/2023.03.13.532443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
General linear models have been the foundational statistical framework used to discover the ecological processes that explain the distribution and abundance of natural populations. Analyses of the rapidly expanding cache of environmental and ecological data, however, require advanced statistical methods to contend with complexities inherent to extremely large natural data sets. Modern machine learning frameworks such as gradient boosted trees efficiently identify complex ecological relationships in massive data sets, which are expected to result in accurate predictions of the distribution and abundance of organisms in nature. However, rigorous assessments of the theoretical advantages of these methodologies on natural data sets are rare. Here we compare the abilities of gradient boosted and linear models to identify environmental features that explain observed variations in the distribution and abundance of blacklegged tick (Ixodes scapularis) populations in a data set collected across New York State over a ten-year period. The gradient boosted and linear models use similar environmental features to explain tick demography, although the gradient boosted models found non-linear relationships and interactions that are difficult to anticipate and often impractical to identify with a linear modeling framework. Further, the gradient boosted models predicted the distribution and abundance of ticks in years and areas beyond the training data with much greater accuracy than their linear model counterparts. The flexible gradient boosting framework also permitted additional model types that provide practical advantages for tick surveillance and public health. The results highlight the potential of gradient boosted models to discover novel ecological phenomena affecting pathogen demography and as a powerful public health tool to mitigate disease risks.
Collapse
|
2
|
Fall P, Diouf I, Deme A, Diouf S, Sene D, Sultan B, Famien AM, Janicot S. Bias-Corrected CMIP5 Projections for Climate Change and Assessments of Impact on Malaria in Senegal under the VECTRI Model. Trop Med Infect Dis 2023; 8:310. [PMID: 37368728 DOI: 10.3390/tropicalmed8060310] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 05/19/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
On the climate-health issue, studies have already attempted to understand the influence of climate change on the transmission of malaria. Extreme weather events such as floods, droughts, or heat waves can alter the course and distribution of malaria. This study aims to understand the impact of future climate change on malaria transmission using, for the first time in Senegal, the ICTP's community-based vector-borne disease model, TRIeste (VECTRI). This biological model is a dynamic mathematical model for the study of malaria transmission that considers the impact of climate and population variability. A new approach for VECTRI input parameters was also used. A bias correction technique, the cumulative distribution function transform (CDF-t) method, was applied to climate simulations to remove systematic biases in the Coupled Model Intercomparison Project Phase 5 (CMIP5) global climate models (GCMs) that could alter impact predictions. Beforehand, we use reference data for validation such as CPC global unified gauge-based analysis of daily precipitation (CPC for Climate Prediction Center), ERA5-land reanalysis, Climate Hazards InfraRed Precipitation with Station data (CHIRPS), and African Rainfall Climatology 2.0 (ARC2). The results were analyzed for two CMIP5 scenarios for the different time periods: assessment: 1983-2005; near future: 2006-2028; medium term: 2030-2052; and far future: 2077-2099). The validation results show that the models reproduce the annual cycle well. Except for the IPSL-CM5B model, which gives a peak in August, all the other models (ACCESS1-3, CanESM2, CSIRO, CMCC-CM, CMCC-CMS, CNRM-CM5, GFDL-CM3, GFDL-ESM2G, GFDL-ESM2M, inmcm4, and IPSL-CM5B) agree with the validation data on a maximum peak in September with a period of strong transmission in August-October. With spatial variation, the CMIP5 model simulations show more of a difference in the number of malaria cases between the south and the north. Malaria transmission is much higher in the south than in the north. However, the results predicted by the models on the occurrence of malaria by 2100 show differences between the RCP8.5 scenario, considered a high emission scenario, and the RCP4.5 scenario, considered an intermediate mitigation scenario. The CanESM2, CMCC-CM, CMCC-CMS, inmcm4, and IPSL-CM5B models predict decreases with the RCP4.5 scenario. However, ACCESS1-3, CSIRO, NRCM-CM5, GFDL-CM3, GFDL-ESM2G, and GFDL-ESM2M predict increases in malaria under all scenarios (RCP4.5 and RCP8.5). The projected decrease in malaria in the future with these models is much more visible in the RCP8.5 scenario. The results of this study are of paramount importance in the climate-health field. These results will assist in decision-making and will allow for the establishment of preventive surveillance systems for local climate-sensitive diseases, including malaria, in the targeted regions of Senegal.
Collapse
Affiliation(s)
- Papa Fall
- Laboratoire Environnement-Ingénierie-Télécommunication-Energies Renouvelables (LEITER), Unité de Formation et de Recherche de Sciences Appliquées et de Technologie, Université Gaston Berger de Saint-Louis, BP 234, Saint-Louis 32000, Senegal
| | - Ibrahima Diouf
- Laboratoire de Physique de l'Atmosphère et de l'Océan-Siméon Fongang, Ecole Supérieure Polytechnique de l'Université Cheikh Anta Diop (UCAD), BP 5085, Dakar-Fann, Dakar 10700, Senegal
| | - Abdoulaye Deme
- Laboratoire Environnement-Ingénierie-Télécommunication-Energies Renouvelables (LEITER), Unité de Formation et de Recherche de Sciences Appliquées et de Technologie, Université Gaston Berger de Saint-Louis, BP 234, Saint-Louis 32000, Senegal
| | - Semou Diouf
- Laboratoire Environnement-Ingénierie-Télécommunication-Energies Renouvelables (LEITER), Unité de Formation et de Recherche de Sciences Appliquées et de Technologie, Université Gaston Berger de Saint-Louis, BP 234, Saint-Louis 32000, Senegal
| | - Doudou Sene
- Programme National de Lutte Contre le Paludisme (PNLP), BP 5085, Dakar-Fann, Dakar 10700, Senegal
| | - Benjamin Sultan
- ESPACE-DEV, Université Montpellier, IRD, Université Guyane, Université Réunion, Université Antilles, Université Avignon, 34093 Montpellier, France
| | - Adjoua Moïse Famien
- Laboratoire d'Océanographie et du Climat: Expérimentations et Approches Numériques (LOCEAN), Sorbonne Université, IRD, CNRS, MNHN, 75005 Paris, France
- Département de Sciences et Techniques, Université Alassane Ouattara de Bouaké, Bouaké 01 BPV 18, Côte d'Ivoire
| | - Serge Janicot
- Laboratoire d'Océanographie et du Climat: Expérimentations et Approches Numériques (LOCEAN), Sorbonne Université, IRD, CNRS, MNHN, 75005 Paris, France
| |
Collapse
|
3
|
Lalmalsawma P, Balasubramani K, James MM, Pautu L, Prasad KA, Sarma DK, Balabaskaran Nina P. Malaria hotspots and climate change trends in the hyper-endemic malaria settings of Mizoram along the India-Bangladesh borders. Sci Rep 2023; 13:4538. [PMID: 36941291 PMCID: PMC10025798 DOI: 10.1038/s41598-023-31632-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 03/15/2023] [Indexed: 03/23/2023] Open
Abstract
India has made tremendous progress in reducing malaria mortality and morbidity in the last decade. Mizoram State in North-East India is one of the few malaria-endemic regions where malaria transmission has continued to remain high. As Mizoram shares international borders with Bangladesh and Myanmar, malaria control in this region is critical for malaria elimination efforts in all the three countries. For identifying hotspots for targeted intervention, malaria data from 385 public health sub-centers across Mizoram were analyzed in the Geographic Information System. Almost all the sub-centers reporting high Annual Parasite Index (> 10) are located in Mizoram's districts that border Bangladesh. Getis-Ord Gi* statistic shows most of the sub-centers located along the Bangladesh border in the Lawngtlai and Lunglei districts to be the malaria hotspots. The hotspots also extended into the Mamit and Siaha districts, especially along the borders of Lawngtlai and Lunglei. Analysis of terrain, climatic, and land use/land cover datasets obtained from the Global Modelling and Assimilation Office and satellite images show Mizoram's western part (Lawngtlai, Lunglei, and Mamit districts) to experience similar topographic and climatic conditions as the bordering Rangamati district in the Chittagong division of Bangladesh. Climatic trends in this region from 1981 to 2021, estimated by the Mann-Kendall test and Sen's slope estimates, show an increasing trend in minimum temperature, relative humidity, rainfall, and the associated shift of climatic pattern (temperate to tropical monsoon) could facilitate malaria transmission. The quasi-Poisson regression model estimates a strong association (p < 0.001) between total malaria cases, temperature range, and elevation. The Kruskal-Wallis H test shows a statistically significant association between malaria cases and forest classes (p < 0.001). A regional coordination and strategic plan are required to eliminate malaria from this hyper-endemic malaria region of North-East India.
Collapse
Affiliation(s)
- Pachuau Lalmalsawma
- Integrated Disease Surveillance Programme, Health and Family Welfare Department, Aizawl, Mizoram, India
| | - K Balasubramani
- Department of Geography, School of Earth Sciences, Central University of Tamil Nadu, Thiruvarur, Tamil Nadu, India
| | - Meenu Mariya James
- Department of Epidemiology and Public Health, Central University of Tamil Nadu, Thiruvarur, Tamil Nadu, India
| | - Lalfakzuala Pautu
- Integrated Disease Surveillance Programme, Health and Family Welfare Department, Aizawl, Mizoram, India
- Department of Life Sciences, Pachhunga University College, Mizoram University, Aizawl, Mizoram, India
| | - Kumar Arun Prasad
- Department of Geography, School of Earth Sciences, Central University of Tamil Nadu, Thiruvarur, Tamil Nadu, India
| | - Devojit Kumar Sarma
- ICMR- National Institute for Research in Environmental Health, Bhopal, Madhya Pradesh, India.
| | - Praveen Balabaskaran Nina
- Department of Epidemiology and Public Health, Central University of Tamil Nadu, Thiruvarur, Tamil Nadu, India.
- Department of Public Health and Community Medicine, Central University of Kerala, Kasaragod, Kerala, India.
| |
Collapse
|
4
|
Otambo WO, Omondi CJ, Ochwedo KO, Onyango PO, Atieli H, Lee MC, Wang C, Zhou G, Githeko AK, Githure J, Ouma C, Yan G, Kazura J. Risk associations of submicroscopic malaria infection in lakeshore, plateau and highland areas of Kisumu County in western Kenya. PLoS One 2022; 17:e0268463. [PMID: 35576208 PMCID: PMC9109926 DOI: 10.1371/journal.pone.0268463] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/29/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Persons with submicroscopic malaria infection are a major reservoir of gametocytes that sustain malaria transmission in sub-Saharan Africa. Despite recent decreases in the national malaria burden in Kenya due to vector control interventions, malaria transmission continues to be high in western regions of the country bordering Lake Victoria. The objective of this study was to advance knowledge of the topographical, demographic and behavioral risk factors associated with submicroscopic malaria infection in the Lake Victoria basin in Kisumu County. METHODS Cross-sectional community surveys for malaria infection were undertaken in three eco-epidemiologically distinct zones in Nyakach sub-County, Kisumu. Adjacent regions were topologically characterized as lakeshore, hillside and highland plateau. Surveys were conducted during the 2019 and 2020 wet and dry seasons. Finger prick blood smears and dry blood spots (DBS) on filter paper were collected from 1,777 healthy volunteers for microscopic inspection and real time-PCR (RT-PCR) diagnosis of Plasmodium infection. Persons who were PCR positive but blood smear negative were considered to harbor submicroscopic infections. Topographical, demographic and behavioral risk factors were correlated with community prevalence of submicroscopic infections. RESULTS Out of a total of 1,777 blood samples collected, 14.2% (253/1,777) were diagnosed as submicroscopic infections. Blood smear microscopy and RT-PCR, respectively, detected 3.7% (66/1,777) and 18% (319/1,777) infections. Blood smears results were exclusively positive for P. falciparum, whereas RT-PCR also detected P. malariae and P. ovale mono- and co-infections. Submicroscopic infection prevalence was associated with topographical variation (χ2 = 39.344, df = 2, p<0.0001). The highest prevalence was observed in the lakeshore zone (20.6%, n = 622) followed by the hillside (13.6%, n = 595) and highland plateau zones (7.9%, n = 560). Infection prevalence varied significantly according to season (χ2 = 17.374, df = 3, p<0.0001). The highest prevalence was observed in residents of the lakeshore zone in the 2019 dry season (29.9%, n = 167) and 2020 and 2019 rainy seasons (21.5%, n = 144 and 18.1%, n = 155, respectively). In both the rainy and dry seasons the likelihood of submicroscopic infection was higher in the lakeshore (AOR: 2.71, 95% CI = 1.85-3.95; p<0.0001) and hillside (AOR: 1.74, 95% CI = 1.17-2.61, p = 0.007) than in the highland plateau zones. Residence in the lakeshore zone (p<0.0001), male sex (p = 0.025), school age (p = 0.002), and living in mud houses (p = 0.044) increased the risk of submicroscopic malaria infection. Bed net use (p = 0.112) and occupation (p = 0.116) were not associated with submicroscopic infection prevalence. CONCLUSION Topographic features of the local landscape and seasonality are major correlates of submicroscopic malaria infection in the Lake Victoria area of western Kenya. Diagnostic tests more sensitive than blood smear microscopy will allow for monitoring and targeting geographic sites where additional vector interventions are needed to reduce malaria transmission.
Collapse
Affiliation(s)
- Wilfred Ouma Otambo
- Department of Zoology, Maseno University, Kisumu, Kenya
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
| | - Collince J. Omondi
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
- Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
| | - Kevin O. Ochwedo
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
- Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
| | | | - Harrysone Atieli
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
| | - Ming-Chieh Lee
- Department of Population Health and Disease Prevention, University of California, Irvine, CA, United States of America
| | - Chloe Wang
- Department of Population Health and Disease Prevention, University of California, Irvine, CA, United States of America
| | - Guofa Zhou
- Department of Population Health and Disease Prevention, University of California, Irvine, CA, United States of America
| | - Andrew K. Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - John Githure
- International Centre of Excellence for Malaria Research, Tom Mboya University College of Maseno University, Homa Bay, Kenya
| | - Collins Ouma
- Department of Biomedical Sciences and Technology, Maseno University, Kisumu, Kenya
| | - Guiyun Yan
- Department of Population Health and Disease Prevention, University of California, Irvine, CA, United States of America
| | - James Kazura
- Centre for Global Health & Diseases, Case Western University Reserve, Cleveland, Ohio, United States of America
| |
Collapse
|
5
|
Hooft AM, Ndenga B, Mutuku F, Otuka V, Ronga C, Chebii PK, Maina PW, Jembe Z, Lee J, Vu DM, Mukoko D, LaBeaud AD. High Frequency of Antibiotic Prescription in Children With Undifferentiated Febrile Illness in Kenya. Clin Infect Dis 2021; 73:e2399-e2406. [PMID: 32882032 PMCID: PMC8492150 DOI: 10.1093/cid/ciaa1305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 09/01/2020] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND In low-resource, malaria-endemic settings, accurate diagnosis of febrile illness in children is challenging. The World Health Organization (WHO) currently recommends laboratory-confirmed diagnosis of malaria prior to starting treatment in stable children. Factors guiding management of children with undifferentiated febrile illness outside of malaria are not well understood. METHODS This study examined clinical presentation and management of a cohort of febrile Kenyan children at 5 hospital/clinic sites from January 2014 to December 2017. Chi-squared and multivariate regression analyses were used to compare frequencies and correlate demographic, environmental, and clinical factors with patient diagnosis and prescription of antibiotics. RESULTS Of 5735 total participants, 68% were prescribed antibiotic treatment (n = 3902), despite only 28% given a diagnosis of bacterial illness (n = 1589). Factors associated with prescription of antibiotic therapy included: negative malaria testing, reporting head, ears, eyes, nose and throat (HEENT) symptoms (ie, cough, runny nose), HEENT findings on exam (ie, nasal discharge, red throat), and having a flush toilet in the home (likely a surrogate for higher socioeconomic status). CONCLUSION In a cohort of acutely ill Kenyan children, prescription of antimalarial therapy and malaria test results were well correlated, whereas antibiotic treatment was prescribed empirically to most of those who tested malaria negative. Clinical management of febrile children in these settings is difficult, given the lack of diagnostic testing. Providers may benefit from improved clinical education and implementation of enhanced guidelines in this era of malaria testing, as their management strategies must rely primarily on critical thinking and decision-making skills.
Collapse
Affiliation(s)
- Anneka M Hooft
- Department of Pediatrics, UCSF Benioff Children’s Hospital Oakland, Oakland, California, USA
- Department of Emergency Medicine, Pediatric Emergency Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Bryson Ndenga
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Francis Mutuku
- Department of Environment and Health Sciences, Technical University of Mombasa, Mombasa, Kenya
| | - Victoria Otuka
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Charles Ronga
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Philip K Chebii
- Department of Pediatrics, Msambweni County Referral Hospital, Msambweni, Kenya
| | - Priscillah W Maina
- Department of Pediatrics, Msambweni County Referral Hospital, Msambweni, Kenya
| | - Zainab Jembe
- Department of Pediatrics, Diani Health Center, Ukunda, Kenya
| | - Justin Lee
- Quantitative Sciences Unit, Department of Medicine, Stanford University, Stanford, California, USA
| | - David M Vu
- Department of Pediatrics, Division of Infectious Disease, Stanford University, Stanford, California, USA
| | | | - A Desiree LaBeaud
- Department of Pediatrics, Division of Infectious Disease, Stanford University, Stanford, California, USA
| |
Collapse
|
6
|
Nosrat C, Altamirano J, Anyamba A, Caldwell JM, Damoah R, Mutuku F, Ndenga B, LaBeaud AD. Impact of recent climate extremes on mosquito-borne disease transmission in Kenya. PLoS Negl Trop Dis 2021; 15:e0009182. [PMID: 33735293 PMCID: PMC7971569 DOI: 10.1371/journal.pntd.0009182] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 01/26/2021] [Indexed: 01/12/2023] Open
Abstract
Climate change and variability influence temperature and rainfall, which impact vector abundance and the dynamics of vector-borne disease transmission. Climate change is projected to increase the frequency and intensity of extreme climate events. Mosquito-borne diseases, such as dengue fever, are primarily transmitted by Aedes aegypti mosquitoes. Freshwater availability and temperature affect dengue vector populations via a variety of biological processes and thus influence the ability of mosquitoes to effectively transmit disease. However, the effect of droughts, floods, heat waves, and cold waves is not well understood. Using vector, climate, and dengue disease data collected between 2013 and 2019 in Kenya, this retrospective cohort study aims to elucidate the impact of extreme rainfall and temperature on mosquito abundance and the risk of arboviral infections. To define extreme periods of rainfall and land surface temperature (LST), we calculated monthly anomalies as deviations from long-term means (1983–2019 for rainfall, 2000–2019 for LST) across four study locations in Kenya. We classified extreme climate events as the upper and lower 10% of these calculated LST or rainfall deviations. Monthly Ae. aegypti abundance was recorded in Kenya using four trapping methods. Blood samples were also collected from children with febrile illness presenting to four field sites and tested for dengue virus using an IgG enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). We found that mosquito eggs and adults were significantly more abundant one month following an abnormally wet month. The relationship between mosquito abundance and dengue risk follows a non-linear association. Our findings suggest that early warnings and targeted interventions during periods of abnormal rainfall and temperature, especially flooding, can potentially contribute to reductions in risk of viral transmission. Dengue is a rapidly spreading mosquito-borne disease transmitted primarily by Aedes aegypti mosquitoes. As climate change leads to extremes in rainfall and temperature, the abundance and populations of these vectors will be affected, thus influencing transmission of dengue. Using satellite-derived climate data for Kenya, we classified months that experienced highly abnormal rainfall and temperature as extreme climate events (floods, droughts, heat waves, or cold waves). We compared the average monthly Ae. aegypti abundance and confirmed dengue counts following extreme climate months using lag periods of one month and two months, respectively. This study utilized several statistical models to account for differences among study sites and time. Floods resulted in significantly increased egg and adult abundance. Our results contributed to a better understanding of the effect of climate variability and change on dengue. As suggested by our observed increase in vector counts yet a relatively unchanged dengue infection risk, human behavior can help reduce viral transmission. Targeted interventions should be focused on both reducing vector populations and limiting human-vector contact, especially during these climate anomalies.
Collapse
Affiliation(s)
- Cameron Nosrat
- Program in Human Biology, Stanford University, Stanford, California, United States of America
- * E-mail:
| | - Jonathan Altamirano
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Assaf Anyamba
- Universities Space Research Association & NASA Goddard Space Flight Center, Greenbelt, Maryland, United States of America
| | - Jamie M. Caldwell
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Richard Damoah
- Morgan State University & NASA Goddard Space Flight Center, Greenbelt, Maryland, United States of America
| | | | - Bryson Ndenga
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - A. Desiree LaBeaud
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| |
Collapse
|
7
|
Goshua A, Gomez J, Erny B, Burke M, Luby S, Sokolow S, LaBeaud AD, Auerbach P, Gisondi MA, Nadeau K. Addressing Climate Change and Its Effects on Human Health: A Call to Action for Medical Schools. ACADEMIC MEDICINE : JOURNAL OF THE ASSOCIATION OF AMERICAN MEDICAL COLLEGES 2021; 96:324-328. [PMID: 33239537 DOI: 10.1097/acm.0000000000003861] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Human health is increasingly threatened by rapid and widespread changes in the environment and climate, including rising temperatures, air and water pollution, disease vector migration, floods, and droughts. In the United States, many medical schools, the American Medical Association, and the National Academy of Sciences have published calls for physicians and physicians-in-training to develop a basic knowledge of the science of climate change and an awareness of the associated health risks. The authors-all medical students and educators-argue for the expeditious redesign of medical school curricula to teach students to recognize, diagnose, and treat the many health conditions exacerbated by climate change as well as understand public health issues. In this Invited Commentary, the authors briefly review the health impacts of climate change, examine current climate change course offerings and proposals, and describe the rationale for promptly and comprehensively including climate science education in medical school curricula. Efforts in training physicians now will benefit those physicians' communities whose health will be impacted by a period of remarkable climate change. The bottom line is that the health effects of climate reality cannot be ignored, and people everywhere must adapt as quickly as possible.
Collapse
Affiliation(s)
- Anna Goshua
- A. Goshua is a second-year medical student, Stanford University School of Medicine, Stanford, California
| | - Jason Gomez
- J. Gomez is a second-year medical student, Stanford University School of Medicine, Stanford, California
| | - Barbara Erny
- B. Erny is medical liaison for international programs, American Society of Cataract and Refractive Surgery Foundation, Fairfax, Virginia, and a member, Environmental Health Committee, Physicians for Social Responsibility, Washington, DC
| | - Marshall Burke
- M. Burke is associate professor, Department of Earth System Science and Center on Food Security and the Environment, Stanford University, Stanford, California
| | - Stephen Luby
- S. Luby is professor of medicine and associate dean of global health research, Stanford University, Stanford, California
| | - Susanne Sokolow
- S. Sokolow is senior research scientist, Stanford Woods Institute for the Environment, Stanford University, Stanford, California
| | - A Desiree LaBeaud
- A.D. LaBeaud is professor of pediatrics, Stanford University School of Medicine, and a senior fellow, Stanford Woods Institute for the Environment, Stanford, California
| | - Paul Auerbach
- P. Auerbach is the Redlich Family Professor Emeritus, Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California
| | - Michael A Gisondi
- M.A. Gisondi is associate professor and vice chair of education, Department of Emergency Medicine, Stanford University, Stanford, California
| | - Kari Nadeau
- K. Nadeau is the Naddisy Family Foundation Professor of Allergy and director, Sean N. Parker Center for Allergy and Asthma Research at Stanford University, Stanford, California
| |
Collapse
|
8
|
Kishoyian G, Njagi ENM, Orinda GO, Kimani FT, Thiongo K, Matoke-Muhia D. Efficacy of artemisinin-lumefantrine for treatment of uncomplicated malaria after more than a decade of its use in Kenya. Epidemiol Infect 2021; 149:e27. [PMID: 33397548 PMCID: PMC8057502 DOI: 10.1017/s0950268820003167] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND The resistance of Plasmodium falciparum to antimalarial drugs remains a major impairment in the treatment and eradication of malaria globally. Following the introduction of artemisinin-based combination therapy (ACT), there have been reports of delayed parasite clearance. In Kenya, artemether-lumefantrine (AL) is the recommended first-line treatment of uncomplicated malaria. This study sought to assess the efficacy of AL after a decade of use as the preferred method of managing malarial infections in Kenya. We assessed clinical and parasitological responses of children under 5 years between May and November 2015 in Chulaimbo sub-County, Kisumu, Kenya. Patients aged between 6 and 60 months with uncomplicated P. falciparum mono-infection, confirmed through microscopy, were enrolled in the study. The patients were admitted at the facility for 3 days, treated with a standard dose of AL, and then put under observation for the next 28 days for the assessment of clinical and parasitological responses. Of the 90 patients enrolled, 14 were lost to follow-up while 76 were followed through to the end of the study period. Seventy-five patients (98.7%) cleared the parasitaemia within a period of 48 h while one patient (1.3%) cleared on day 3. There was 100% adequate clinical and parasitological response. All the patients cleared the parasites on day 3 and there were no re-infections observed during the stated follow-up period. This study, therefore, concludes that AL is highly efficacious in clearing P. falciparum parasites in children aged ≥6 and ≤60 months. The study, however, underscores the need for continued monitoring of the drug to forestall both gradual ineffectiveness and possible resistance to the drug in all target users.
Collapse
Affiliation(s)
- Gabriel Kishoyian
- Department of Medical Laboratory Sciences, Kenya Medical Training College, P.O. Box2268-40100, Kisumu, Kenya
| | - Eliud N. M. Njagi
- Department of Biochemistry and Biotechnology, Kenyatta University, P.O.BOX 43844-00100, Nairobi, Kenya
| | - George O. Orinda
- Department of Biochemistry and Biotechnology, Kenyatta University, P.O.BOX 43844-00100, Nairobi, Kenya
| | - Francis T. Kimani
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya
| | - Kevin Thiongo
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya
| | - Damaris Matoke-Muhia
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya
| |
Collapse
|
9
|
Emeto TI, Adegboye OA, Rumi RA, Khan MUI, Adegboye M, Khan WA, Rahman M, Streatfield PK, Rahman KM. Disparities in Risks of Malaria Associated with Climatic Variability among Women, Children and Elderly in the Chittagong Hill Tracts of Bangladesh. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E9469. [PMID: 33348771 PMCID: PMC7766360 DOI: 10.3390/ijerph17249469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/09/2020] [Accepted: 12/15/2020] [Indexed: 12/04/2022]
Abstract
Malaria occurrence in the Chittagong Hill Tracts in Bangladesh varies by season and year, but this pattern is not well characterized. The role of environmental conditions on the occurrence of this vector-borne parasitic disease in the region is not fully understood. We extracted information on malaria patients recorded in the Upazila (sub-district) Health Complex patient registers of Rajasthali in Rangamati district of Bangladesh from February 2000 to November 2009. Weather data for the study area and period were obtained from the Bangladesh Meteorological Department. Non-linear and delayed effects of meteorological drivers, including temperature, relative humidity, and rainfall on the incidence of malaria, were investigated. We observed significant positive association between temperature and rainfall and malaria occurrence, revealing two peaks at 19 °C (logarithms of relative risks (logRR) = 4.3, 95% CI: 1.1-7.5) and 24.5 °C (logRR = 4.7, 95% CI: 1.8-7.6) for temperature and at 86 mm (logRR = 19.5, 95% CI: 11.7-27.3) and 284 mm (logRR = 17.6, 95% CI: 9.9-25.2) for rainfall. In sub-group analysis, women were at a much higher risk of developing malaria at increased temperatures. People over 50 years and children under 15 years were more susceptible to malaria at increased rainfall. The observed associations have policy implications. Further research is needed to expand these findings and direct resources to the vulnerable populations for malaria prevention and control in the Chittagong Hill Tracts of Bangladesh and the region with similar settings.
Collapse
Affiliation(s)
- Theophilus I. Emeto
- Public Health & Tropical Medicine, College of Public Health, Medical & Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia;
| | - Oyelola A. Adegboye
- Public Health & Tropical Medicine, College of Public Health, Medical & Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia;
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD 4811, Australia
| | - Reza A. Rumi
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka 1212, Bangladesh; (R.A.R.); (M.-U.I.K.); (W.A.K.); (P.K.S.)
| | - Mahboob-Ul I. Khan
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka 1212, Bangladesh; (R.A.R.); (M.-U.I.K.); (W.A.K.); (P.K.S.)
| | | | - Wasif A. Khan
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka 1212, Bangladesh; (R.A.R.); (M.-U.I.K.); (W.A.K.); (P.K.S.)
| | - Mahmudur Rahman
- Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka 1212, Bangladesh;
| | - Peter K. Streatfield
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka 1212, Bangladesh; (R.A.R.); (M.-U.I.K.); (W.A.K.); (P.K.S.)
| | - Kazi M. Rahman
- North Coast Public Health Unit, New South Wales Health, Lismore, NSW 2480, Australia;
- The University of Sydney, University Centre for Rural Health, Lismore, NSW 2480, Australia
| |
Collapse
|
10
|
Ngugi HN, Nyathi S, Krystosik A, Ndenga B, Mbakaya JO, Aswani P, Musunzaji PS, Irungu LW, Bisanzio D, Kitron U, Desiree LaBeaud A, Mutuku F. Risk factors for Aedes aegypti household pupal persistence in longitudinal entomological household surveys in urban and rural Kenya. Parasit Vectors 2020; 13:499. [PMID: 33004074 PMCID: PMC7528257 DOI: 10.1186/s13071-020-04378-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 09/23/2020] [Indexed: 12/31/2022] Open
Abstract
Background Aedes aegypti is an efficient vector of several arboviruses of public health importance, including Zika and dengue. Currently vector management is the only available avenue for disease control. Development of efficient vector control strategies requires a thorough understanding of vector ecology. In this study, we identified households that are consistently productive for Ae. aegypti pupae and determined the ecological and socio-demographic factors associated with the persistence and abundance of pupae in households in rural and urban Kenya. Methods We collected socio-demographic, environmental and entomological data monthly from July 2014 to June 2018 from 80 households across four sites in Kenya. Pupae count data were collected via entomological surveillance of households and paired with socio-demographic and environmental data. We calculated pupal persistence within a household as the number of months of pupal presence within a year. We used spatially explicit generalized additive mixed models (GAMMs) to identify the risk factors for pupal abundance, and a logistic regression to identify the risk factors for pupal persistence in households. Results The median number of months of pupal presence observed in households was 4 and ranged from 0 to 35 months. We identified pupal persistence in 85 house-years. The strongest risk factors for high pupal abundance were the presence of bushes or tall grass in the peri-domicile area (OR: 1.60, 95% CI: 1.13–2.28), open eaves (OR: 2.57, 95% CI: 1.33–4.95) and high habitat counts (OR: 1.42, 95% CI: 1.21–1.66). The main risk factors for pupal persistence were the presence of bushes or tall grass in the peri-domicile (OR: 4.20, 95% CI: 1.42–12.46) and high number of breeding sites (OR: 2.17, 95% CI: 1.03–4.58). Conclusions We observed Ae. aegypti pupal persistence at the household level in urban and rural and in coastal and inland Kenya. High counts of potential breeding containers, vegetation in the peri-domicile area and the presence of eaves were strongly associated with increased risk of pupal persistence and abundance. Targeting households that exhibit pupal persistence alongside the risk factors for pupal abundance in vector control interventions may result in more efficient use of limited resources.![]()
Collapse
Affiliation(s)
- Harun N Ngugi
- School of Biological Sciences, Department of Zoology, University of Nairobi, Nairobi, Kenya.,Department of Biological Sciences, Chuka University, Chuka, Kenya
| | - Sindiso Nyathi
- Department of Epidemiology and Population Health, School of Medicine, Stanford University, Stanford, CA, USA
| | - Amy Krystosik
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Stanford University, Stanford, CA, USA
| | - Bryson Ndenga
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Joel O Mbakaya
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Peter Aswani
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | | | - Lucy W Irungu
- School of Biological Sciences, Department of Zoology, University of Nairobi, Nairobi, Kenya
| | - Donal Bisanzio
- RTI International, Washington, DC, USA.,Epidemiology and Public Health Division, School of Medicine, University of Nottingham, Nottingham, UK
| | - Uriel Kitron
- Department of Environmental Sciences, Emory University, Atlanta, GA, USA
| | - A Desiree LaBeaud
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Stanford University, Stanford, CA, USA
| | - Francis Mutuku
- Department of Environment and Health Sciences, Technical University of Mombasa, Mombasa, Kenya.
| |
Collapse
|
11
|
Shocket MS, Verwillow AB, Numazu MG, Slamani H, Cohen JM, El Moustaid F, Rohr J, Johnson LR, Mordecai EA. Transmission of West Nile and five other temperate mosquito-borne viruses peaks at temperatures between 23°C and 26°C. eLife 2020; 9:e58511. [PMID: 32930091 PMCID: PMC7492091 DOI: 10.7554/elife.58511] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 08/18/2020] [Indexed: 12/22/2022] Open
Abstract
The temperature-dependence of many important mosquito-borne diseases has never been quantified. These relationships are critical for understanding current distributions and predicting future shifts from climate change. We used trait-based models to characterize temperature-dependent transmission of 10 vector-pathogen pairs of mosquitoes (Culex pipiens, Cx. quinquefascsiatus, Cx. tarsalis, and others) and viruses (West Nile, Eastern and Western Equine Encephalitis, St. Louis Encephalitis, Sindbis, and Rift Valley Fever viruses), most with substantial transmission in temperate regions. Transmission is optimized at intermediate temperatures (23-26°C) and often has wider thermal breadths (due to cooler lower thermal limits) compared to pathogens with predominately tropical distributions (in previous studies). The incidence of human West Nile virus cases across US counties responded unimodally to average summer temperature and peaked at 24°C, matching model-predicted optima (24-25°C). Climate warming will likely shift transmission of these diseases, increasing it in cooler locations while decreasing it in warmer locations.
Collapse
Affiliation(s)
- Marta S Shocket
- Department of Biology, Stanford UniversityStanfordUnited States
- Department of Ecology and Evolutionary Biology, University of California Los AngelesLos AngelesUnited States
| | | | - Mailo G Numazu
- Department of Biology, Stanford UniversityStanfordUnited States
| | - Hani Slamani
- Department of Statistics, Virginia Polytechnic Institute and State University (Virginia Tech)BlacksburgUnited States
| | - Jeremy M Cohen
- Department of Integrative Biology, University of South FloridaTampaUnited States
- Department of Forest and Wildlife Ecology, University of WisconsinMadisonUnited States
| | - Fadoua El Moustaid
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech)BlacksburgUnited States
| | - Jason Rohr
- Department of Integrative Biology, University of South FloridaTampaUnited States
- Department of Biological Sciences, Eck Institute of Global Health, Environmental Change Initiative, University of Notre DameSouth BendUnited States
| | - Leah R Johnson
- Department of Statistics, Virginia Polytechnic Institute and State University (Virginia Tech)BlacksburgUnited States
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech)BlacksburgUnited States
| | - Erin A Mordecai
- Department of Biology, Stanford UniversityStanfordUnited States
| |
Collapse
|
12
|
Mordecai EA, Ryan SJ, Caldwell JM, Shah MM, LaBeaud AD. Climate change could shift disease burden from malaria to arboviruses in Africa. Lancet Planet Health 2020; 4:e416-e423. [PMID: 32918887 PMCID: PMC7490804 DOI: 10.1016/s2542-5196(20)30178-9] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 05/28/2023]
Abstract
Malaria is a long-standing public health problem in sub-Saharan Africa, whereas arthropod-borne viruses (arboviruses) such as dengue and chikungunya cause an under-recognised burden of disease. Many human and environmental drivers affect the dynamics of vector-borne diseases. In this Personal View, we argue that the direct effects of warming temperatures are likely to promote greater environmental suitability for dengue and other arbovirus transmission by Aedes aegypti and reduce suitability for malaria transmission by Anopheles gambiae. Environmentally driven changes in disease dynamics will be complex and multifaceted, but given that current public efforts are targeted to malaria control, we highlight Ae aegypti and dengue, chikungunya, and other arboviruses as potential emerging public health threats in sub-Saharan Africa.
Collapse
Affiliation(s)
- Erin A. Mordecai
- Biology Department, Stanford University, 371 Serra Mall, Stanford, CA, United States
| | - Sadie J. Ryan
- Department of Geography, University of Florida, Gainesville, FL, United States; Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States; School of Life Sciences, College of Agriculture, Engineering, and Science, University of KwaZulu Natal, KwaZulu Natal, South Africa
| | - Jamie M. Caldwell
- Biology Department, Stanford University, 371 Serra Mall, Stanford, CA, United States
| | - Melisa M. Shah
- Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA, United States
| | - A. Desiree LaBeaud
- Department of Pediatrics, Division of Infectious Disease, School of Medicine, Stanford University, Stanford, CA, United States
| |
Collapse
|
13
|
Pathak AK, Shiau JC, Thomas MB, Murdock CC. Field Relevant Variation in Ambient Temperature Modifies Density-Dependent Establishment of Plasmodium falciparum Gametocytes in Mosquitoes. Front Microbiol 2019; 10:2651. [PMID: 31803169 PMCID: PMC6873802 DOI: 10.3389/fmicb.2019.02651] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/30/2019] [Indexed: 12/29/2022] Open
Abstract
The relationship between Plasmodium falciparum gametocyte density and infections in mosquitoes is central to understanding the rates of transmission with important implications for control. Here, we determined whether field relevant variation in environmental temperature could also modulate this relationship. Anopheles stephensi were challenged with three densities of P. falciparum gametocytes spanning a ~10-fold gradient, and housed under diurnal/daily temperature range ("DTR") of 9°C (+5°C and -4°C) around means of 20, 24, and 28°C. Vector competence was quantified as the proportion of mosquitoes infected with oocysts in the midguts (oocyst rates) or infectious with sporozoites in the salivary glands (sporozoite rates) at peak periods of infection for each temperature to account for the differences in development rates. In addition, oocyst intensities were also recorded from infected midguts and the overall study replicated across three separate parasite cultures and mosquito cohorts. While vector competence was similar at 20 DTR 9°C and 24 DTR 9°C, oocyst and sporozoite rates were also comparable, with evidence, surprisingly, for higher vector competence in mosquitoes challenged with intermediate gametocyte densities. For the same gametocyte densities however, severe reductions in the sporozoite rates was accompanied by a significant decline in overall vector competence at 28 DTR 9°C, with gametocyte density per se showing a positive and linear effect at this temperature. Unlike vector competence, oocyst intensities decreased with increasing temperatures with a predominantly positive and linear association with gametocyte density, especially at 28 DTR 9°C. Oocyst intensities across individual infected midguts suggested temperature-specific differences in mosquito susceptibility/resistance: at 20 DTR 9°C and 24 DTR 9°C, dispersion (aggregation) increased in a density-dependent manner but not at 28 DTR 9°C where the distributions were consistently random. Limitations notwithstanding, our results suggest that variation in temperature could modify seasonal dynamics of infectious reservoirs with implications for the design and deployment of transmission-blocking vaccines/drugs.
Collapse
Affiliation(s)
- Ashutosh K. Pathak
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
- Center for Ecology of Infectious Diseases, University of Georgia, Athens, GA, United States
- Center for Tropical Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Justine C. Shiau
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Matthew B. Thomas
- The Department of Entomology, Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, United States
| | - Courtney C. Murdock
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
- Center for Ecology of Infectious Diseases, University of Georgia, Athens, GA, United States
- Center for Tropical Emerging Global Diseases, University of Georgia, Athens, GA, United States
- Odum School of Ecology, University of Georgia, Athens, GA, United States
- Center for Vaccines and Immunology, University of Georgia, Athens, GA, United States
- Riverbasin Center, University of Georgia, Athens, GA, United States
| |
Collapse
|
14
|
Amazon deforestation drives malaria transmission, and malaria burden reduces forest clearing. Proc Natl Acad Sci U S A 2019; 116:22212-22218. [PMID: 31611369 DOI: 10.1073/pnas.1905315116] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Deforestation and land use change are among the most pressing anthropogenic environmental impacts. In Brazil, a resurgence of malaria in recent decades paralleled rapid deforestation and settlement in the Amazon basin, yet evidence of a deforestation-driven increase in malaria remains equivocal. We hypothesize an underlying cause of this ambiguity is that deforestation and malaria influence each other in bidirectional causal relationships-deforestation increases malaria through ecological mechanisms and malaria reduces deforestation through socioeconomic mechanisms-and that the strength of these relationships depends on the stage of land use transformation. We test these hypotheses with a large geospatial dataset encompassing 795 municipalities across 13 y (2003 to 2015) and show deforestation has a strong positive effect on malaria incidence. Our results suggest a 10% increase in deforestation leads to a 3.3% increase in malaria incidence (∼9,980 additional cases associated with 1,567 additional km2 lost in 2008, the study midpoint, Amazon-wide). The effect is larger in the interior and absent in outer Amazonian states where little forest remains. However, this strong effect is only detectable after controlling for a feedback of malaria burden on forest loss, whereby increased malaria burden significantly reduces forest clearing, possibly mediated by human behavior or economic development. We estimate a 1% increase in malaria incidence results in a 1.4% decrease in forest area cleared (∼219 fewer km2 cleared associated with 3,024 additional cases in 2008). This bidirectional socioecological feedback between deforestation and malaria, which attenuates as land use intensifies, illustrates the intimate ties between environmental change and human health.
Collapse
|
15
|
Mordecai EA, Caldwell JM, Grossman MK, Lippi CA, Johnson LR, Neira M, Rohr JR, Ryan SJ, Savage V, Shocket MS, Sippy R, Stewart Ibarra AM, Thomas MB, Villena O. Thermal biology of mosquito-borne disease. Ecol Lett 2019; 22:1690-1708. [PMID: 31286630 PMCID: PMC6744319 DOI: 10.1111/ele.13335] [Citation(s) in RCA: 238] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/22/2019] [Accepted: 06/06/2019] [Indexed: 12/11/2022]
Abstract
Mosquito-borne diseases cause a major burden of disease worldwide. The vital rates of these ectothermic vectors and parasites respond strongly and nonlinearly to temperature and therefore to climate change. Here, we review how trait-based approaches can synthesise and mechanistically predict the temperature dependence of transmission across vectors, pathogens, and environments. We present 11 pathogens transmitted by 15 different mosquito species - including globally important diseases like malaria, dengue, and Zika - synthesised from previously published studies. Transmission varied strongly and unimodally with temperature, peaking at 23-29ºC and declining to zero below 9-23ºC and above 32-38ºC. Different traits restricted transmission at low versus high temperatures, and temperature effects on transmission varied by both mosquito and parasite species. Temperate pathogens exhibit broader thermal ranges and cooler thermal minima and optima than tropical pathogens. Among tropical pathogens, malaria and Ross River virus had lower thermal optima (25-26ºC) while dengue and Zika viruses had the highest (29ºC) thermal optima. We expect warming to increase transmission below thermal optima but decrease transmission above optima. Key directions for future work include linking mechanistic models to field transmission, combining temperature effects with control measures, incorporating trait variation and temperature variation, and investigating climate adaptation and migration.
Collapse
Affiliation(s)
- Erin A. Mordecai
- Department of BiologyStanford University371 Serra MallStanfordCAUSA
| | | | - Marissa K. Grossman
- Department of Entomology and Center for Infectious Disease DynamicsPenn State UniversityUniversity ParkPA16802USA
| | - Catherine A. Lippi
- Department of Geography and Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
| | - Leah R. Johnson
- Department of StatisticsVirginia Polytechnic and State University250 Drillfield DriveBlacksburgVAUSA
| | - Marco Neira
- Center for Research on Health in Latin America (CISeAL)Pontificia Universidad Católica del EcuadorQuitoEcuador
| | - Jason R. Rohr
- Department of Biological SciencesEck Institute of Global HealthEnvironmental Change InitiativeUniversity of Notre Dame, Notre DameINUSA
| | - Sadie J. Ryan
- Department of Geography and Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
- School of Life SciencesUniversity of KwaZulu‐NatalDurbanSouth Africa
| | - Van Savage
- Department of Ecology and Evolutionary Biology and Department of BiomathematicsUniversity of California Los AngelesLos AngelesCA90095USA
- Santa Fe Institute1399 Hyde Park RdSanta FeNM87501USA
| | - Marta S. Shocket
- Department of BiologyStanford University371 Serra MallStanfordCAUSA
| | - Rachel Sippy
- Department of Geography and Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
- Institute for Global Health and Translational SciencesSUNY Upstate Medical UniversitySyracuseNY13210USA
| | - Anna M. Stewart Ibarra
- Institute for Global Health and Translational SciencesSUNY Upstate Medical UniversitySyracuseNY13210USA
| | - Matthew B. Thomas
- Department of Entomology and Center for Infectious Disease DynamicsPenn State UniversityUniversity ParkPA16802USA
| | - Oswaldo Villena
- Department of StatisticsVirginia Polytechnic and State University250 Drillfield DriveBlacksburgVAUSA
| |
Collapse
|