1
|
Turner EA, Christofferson RC. Exploring the transmission modalities of Bunyamwera virus. Exp Biol Med (Maywood) 2024; 249:10114. [PMID: 38510492 PMCID: PMC10954195 DOI: 10.3389/ebm.2024.10114] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 12/11/2023] [Indexed: 03/22/2024] Open
Abstract
Bunyamwera virus (BUNV) (Bunyamwera orthobunyavirus) has been found in Sub-Saharan Africa and demonstrated recently as cocirculating with Rift Valley Fever Virus (RVFV). Little is known regarding the breadth of transmission modalities of Bunyamwera. Given its co-occurence with RVFV, we hypothesized the transmission system of BUNV shared similarities to the RVFV system including transmission by Ae. aegypti mosquitoes and environmentally mediated transmission through fomites and environmental contamination. We exposed Ae. aegypti mosquitoes to BUNV and evaluated their ability to transmit both vertically and horizontally. Further, we investigated the potential for a novel transmission modality via environmental contamination. We found that the LSU colony of Ae. aegypti was not competent for the virus for either horizontal or vertical transmission; but, 20% of larva exposed to virus via contaminated aquatic habitat were positive. However, transstadial clearance of the virus was absolute. Finally, under simulated temperature conditions that matched peak transmission in Rwanda, we found that BUNV was stable in both whole blood and serum for up to 28 days at higher total volume in tubes at moderate quantities (103-5 genome copies/mL). In addition, infectiousness of these samples was demonstrated in 80% of the replicates. At lower volume samples (in plates), infectiousness was retained out to 6-8 days with a maximum infectious titer of 104 PFU/mL. Thus, the potential for contamination of the environment and/or transmission via contaminated fomites exists. Our findings have implications for biosafety and infection control, especially in the context of food animal production.
Collapse
|
2
|
Pepin KM, Leach CB, Barrett NL, Ellis JW, VanDalen KK, Webb CT, Shriner SA. Environmental transmission of influenza A virus in mallards. mBio 2023; 14:e0086223. [PMID: 37768062 PMCID: PMC10653830 DOI: 10.1128/mbio.00862-23] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 08/07/2023] [Indexed: 09/29/2023] Open
Abstract
IMPORTANCE Wild birds are the natural reservoir hosts of influenza A viruses. Highly pathogenic strains of influenza A viruses pose risks to wild birds, poultry, and human health. Thus, understanding how these viruses are transmitted between birds is critical. We conducted an experiment where we experimentally infected mallards which are ducks that are commonly exposed to influenza viruses. We exposed several contact ducks to the experimentally infected duck to estimate the probability that a contact duck would become infected from either exposure to the virus shed directly from the infected duck or shared water contaminated with the virus from the infected duck. We found that environmental transmission from contaminated water best predicted the probability of transmission to naïve contact ducks, relatively low levels of virus in the water were sufficient to cause infection, and the probability of a naïve duck becoming infected varied over time.
Collapse
Affiliation(s)
- Kim M. Pepin
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA
| | - Clinton B. Leach
- Department of Fish Wildlife and Conservation Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Nicole L. Barrett
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA
| | - Jeremy W. Ellis
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA
| | - Kaci K. VanDalen
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA
| | - Colleen T. Webb
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
| | - Susan A. Shriner
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA
| |
Collapse
|
3
|
Laggan NA, Parise KL, White JP, Kaarakka HM, Redell JA, DePue JE, Scullon WH, Kath J, Foster JT, Kilpatrick AM, Langwig KE, Hoyt JR. Host infection and disease-induced mortality modify species contributions to the environmental reservoir. Ecology 2023; 104:e4147. [PMID: 37522873 DOI: 10.1002/ecy.4147] [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] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/03/2023] [Accepted: 06/22/2023] [Indexed: 08/01/2023]
Abstract
Environmental pathogen reservoirs exist for many globally important diseases and can fuel epidemics, influence pathogen evolution, and increase the threat of host extinction. Species composition can be an important factor that shapes reservoir dynamics and ultimately determines the outcome of a disease outbreak. However, disease-induced mortality can change species communities, indicating that species responsible for environmental reservoir maintenance may change over time. Here we examine the reservoir dynamics of Pseudogymnoascus destructans, the fungal pathogen that causes white-nose syndrome in bats. We quantified changes in pathogen shedding, infection prevalence and intensity, host abundance, and the subsequent propagule pressure imposed by each species over time. We find that highly shedding species are important during pathogen invasion, but contribute less over time to environmental contamination as they also suffer the greatest declines. Less infected species remain more abundant, resulting in equivalent or higher propagule pressure. More broadly, we demonstrate that high infection intensity and subsequent mortality during disease progression can reduce the contributions of high-shedding species to long-term pathogen maintenance.
Collapse
Affiliation(s)
- Nichole A Laggan
- Department of Biological Sciences, Virginia Polytechnic Institute, Blacksburg, Virginia, USA
| | - Katy L Parise
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - J Paul White
- Wisconsin Department of Natural Resources, Madison, Wisconsin, USA
| | | | | | - John E DePue
- Michigan Department of Natural Resources, Baraga, Michigan, USA
| | | | - Joseph Kath
- Illinois Department of Natural Resources, Springfield, Illinois, USA
| | - Jeffrey T Foster
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - A Marm Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, California, USA
| | - Kate E Langwig
- Department of Biological Sciences, Virginia Polytechnic Institute, Blacksburg, Virginia, USA
| | - Joseph R Hoyt
- Department of Biological Sciences, Virginia Polytechnic Institute, Blacksburg, Virginia, USA
| |
Collapse
|
4
|
Chang Y, Hartemink N, Byrne AW, Gormley E, McGrath G, Tratalos JA, Breslin P, More SJ, de Jong MCM. Inferring bovine tuberculosis transmission between cattle and badgers via the environment and risk mapping. Front Vet Sci 2023; 10:1233173. [PMID: 37841461 PMCID: PMC10572351 DOI: 10.3389/fvets.2023.1233173] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 08/29/2023] [Indexed: 10/17/2023] Open
Abstract
Bovine tuberculosis (bTB), caused by Mycobacterium bovis, is one of the most challenging and persistent health issues in many countries worldwide. In several countries, bTB control is complicated due to the presence of wildlife reservoirs of infection, i.e. European badger (Meles meles) in Ireland and the UK, which can transmit infection to cattle. However, a quantitative understanding of the role of cattle and badgers in bTB transmission is elusive, especially where there is spatial variation in relative density between badgers and cattle. Moreover, as these two species have infrequent direct contact, environmental transmission is likely to play a role, but the quantitative importance of the environment has not been assessed. Therefore, the objective of this study is to better understand bTB transmission between cattle and badgers via the environment in a spatially explicit context and to identify high-risk areas. We developed an environmental transmission model that incorporates both within-herd/territory transmission and between-species transmission, with the latter facilitated by badger territories overlapping with herd areas. Model parameters such as transmission rate parameters and the decay rate parameter of M. bovis were estimated by maximum likelihood estimation using infection data from badgers and cattle collected during a 4-year badger vaccination trial. Our estimation showed that the environment can play an important role in the transmission of bTB, with a half-life of M. bovis in the environment of around 177 days. Based on the estimated transmission rate parameters, we calculate the basic reproduction ratio (R) within a herd, which reveals how relative badger density dictates transmission. In addition, we simulated transmission in each small local area to generate a first between-herd R map that identifies high-risk areas.
Collapse
Affiliation(s)
- You Chang
- Quantitative Veterinary Epidemiology Group, Wageningen University and Research Centre, Wageningen, Netherlands
| | - Nienke Hartemink
- Quantitative Veterinary Epidemiology Group, Wageningen University and Research Centre, Wageningen, Netherlands
- Biometris, Wageningen University and Research Centre, Wageningen, Netherlands
| | - Andrew W. Byrne
- One-Health and Welfare Scientific Support Unit, Department of Agriculture, Food and the Marine, National Disease Control Centre, Dublin, Ireland
| | - Eamonn Gormley
- Tuberculosis Diagnostics and Immunology Research Centre, School of Agriculture, Food Science, and Veterinary Medicine, College of Life Sciences, University College Dublin, Dublin, Ireland
| | - Guy McGrath
- Centre for Veterinary Epidemiology and Risk Analysis, School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - Jamie A. Tratalos
- Centre for Veterinary Epidemiology and Risk Analysis, School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - Philip Breslin
- Ruminant Animal Health Division, Department of Agriculture, Food and the Marine, Dublin, Ireland
| | - Simon J. More
- Centre for Veterinary Epidemiology and Risk Analysis, School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - Mart C. M. de Jong
- Quantitative Veterinary Epidemiology Group, Wageningen University and Research Centre, Wageningen, Netherlands
| |
Collapse
|
5
|
Zbrozek M, Fearon ML, Weise C, Tibbetts EA. Honeybee visitation to shared flowers increases Vairimorpha ceranae prevalence in bumblebees. Ecol Evol 2023; 13:e10528. [PMID: 37736280 PMCID: PMC10511299 DOI: 10.1002/ece3.10528] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/16/2023] [Accepted: 08/31/2023] [Indexed: 09/23/2023] Open
Abstract
Vairimorpha (=Nosema) ceranae is a widespread pollinator parasite that commonly infects honeybees and wild pollinators, including bumblebees. Honeybees are highly competent V. ceranae hosts and previous work in experimental flight cages suggests V. ceranae can be transmitted during visitation to shared flowers. However, the relationship between floral visitation in the natural environment and the prevalence of V. ceranae among multiple bee species has not been explored. Here, we analyzed the number and duration of pollinator visits to particular components of squash flowers-including the petals, stamen, and nectary-at six farms in southeastern Michigan, USA. We also determined the prevalence of V. ceranae in honeybees and bumblebees at each site. Our results showed that more honeybee flower contacts and longer duration of contacts with pollen and nectar were linked with greater V. ceranae prevalence in bumblebees. Honeybee visitation patterns appear to have a disproportionately large impact on V. ceranae prevalence in bumblebees even though honeybees are not the most frequent flower visitors. Floral visitation by squash bees or other pollinators was not linked with V. ceranae prevalence in bumblebees. Further, V. ceranae prevalence in honeybees was unaffected by floral visitation behaviors by any pollinator species. These results suggest that honeybee visitation behaviors on shared floral resources may be an important contributor to increased V. ceranae spillover to bumblebees in the field. Understanding how V. ceranae prevalence is influenced by pollinator behavior in the shared floral landscape is critical for reducing parasite spillover into declining wild bee populations.
Collapse
Affiliation(s)
- Maryellen Zbrozek
- Department of Ecology & Evolutionary BiologyUniversity of MichiganAnn ArborMichiganUSA
| | - Michelle L. Fearon
- Department of Ecology & Evolutionary BiologyUniversity of MichiganAnn ArborMichiganUSA
| | - Chloe Weise
- Department of Ecology & Evolutionary BiologyUniversity of MichiganAnn ArborMichiganUSA
| | - Elizabeth A. Tibbetts
- Department of Ecology & Evolutionary BiologyUniversity of MichiganAnn ArborMichiganUSA
| |
Collapse
|
6
|
Ringwaldt EM, Brook BW, Buettel JC, Cunningham CX, Fuller C, Gardiner R, Hamer R, Jones M, Martin AM, Carver S. Host, environment, and anthropogenic factors drive landscape dynamics of an environmentally transmitted pathogen: Sarcoptic mange in the bare-nosed wombat. J Anim Ecol 2023; 92:1786-1801. [PMID: 37221666 DOI: 10.1111/1365-2656.13960] [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: 12/21/2022] [Accepted: 05/09/2023] [Indexed: 05/25/2023]
Abstract
Understanding the spatial dynamics and drivers of wildlife pathogens is constrained by sampling logistics, with implications for advancing the field of landscape epidemiology and targeted allocation of management resources. However, visually apparent wildlife diseases, when combined with remote-surveillance and distribution modelling technologies, present an opportunity to overcome this landscape-scale problem. Here, we investigated dynamics and drivers of landscape-scale wildlife disease, using clinical signs of sarcoptic mange (caused by Sarcoptes scabiei) in its bare-nosed wombat (BNW; Vombatus ursinus) host. We used 53,089 camera-trap observations from over 3261 locations across the 68,401 km2 area of Tasmania, Australia, combined with landscape data and ensemble species distribution modelling (SDM). We investigated: (1) landscape variables predicted to drive habitat suitability of the host; (2) host and landscape variables associated with clinical signs of disease in the host; and (3) predicted locations and environmental conditions at greatest risk of disease occurrence, including some Bass Strait islands where BNW translocations are proposed. We showed that the Tasmanian landscape, and ecosystems therein, are nearly ubiquitously suited to BNWs. Only high mean annual precipitation reduced habitat suitability for the host. In contrast, clinical signs of sarcoptic mange disease in BNWs were widespread, but heterogeneously distributed across the landscape. Mange (which is environmentally transmitted in BNWs) was most likely to be observed in areas of increased host habitat suitability, lower annual precipitation, near sources of freshwater and where topographic roughness was minimal (e.g. human modified landscapes, such as farmland and intensive land-use areas, shrub and grass lands). Thus, a confluence of host, environmental and anthropogenic variables appear to influence the risk of environmental transmission of S. scabiei. We identified that the Bass Strait Islands are highly suitable for BNWs and predicted a mix of high and low suitability for the pathogen. This study is the largest spatial assessment of sarcoptic mange in any host species, and advances understanding of the landscape epidemiology of environmentally transmitted S. scabiei. This research illustrates how host-pathogen co-suitability can be useful for allocating management resources in the landscape.
Collapse
Affiliation(s)
- E M Ringwaldt
- School of Natural Sciences, Biological Science, University of Tasmania, Hobart, Tasmania, Australia
| | - B W Brook
- School of Natural Sciences, Biological Science, University of Tasmania, Hobart, Tasmania, Australia
| | - J C Buettel
- School of Natural Sciences, Biological Science, University of Tasmania, Hobart, Tasmania, Australia
| | - C X Cunningham
- School of Natural Sciences, Biological Science, University of Tasmania, Hobart, Tasmania, Australia
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
| | - C Fuller
- School of Natural Sciences, Biological Science, University of Tasmania, Hobart, Tasmania, Australia
| | - R Gardiner
- School of Science, Engineering and Technology, University of Sunshine Coast, Sippy Downs, Queensland, Australia
| | - R Hamer
- School of Natural Sciences, Biological Science, University of Tasmania, Hobart, Tasmania, Australia
| | - M Jones
- School of Natural Sciences, Biological Science, University of Tasmania, Hobart, Tasmania, Australia
| | - A M Martin
- Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, Texas, USA
| | - S Carver
- School of Natural Sciences, Biological Science, University of Tasmania, Hobart, Tasmania, Australia
| |
Collapse
|
7
|
Carver S, Lewin ZM, Burgess LG, Wilkinson V, Whitehead J, Driessen MM. Density independent decline from an environmentally transmitted parasite. Biol Lett 2023; 19:20230169. [PMID: 37607579 PMCID: PMC10444343 DOI: 10.1098/rsbl.2023.0169] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/04/2023] [Indexed: 08/24/2023] Open
Abstract
Invasive environmentally transmitted parasites have the potential to cause declines in host populations independent of host density, but this is rarely characterized in naturally occurring populations. We investigated (1) epidemiological features of a declining bare-nosed wombat (Vombatus ursinus) population in central Tasmania owing to a sarcoptic mange (agent Sarcoptes scabiei) outbreak, and (2) reviewed all longitudinal wombat-mange studies to improve our understanding of when host population declines may occur. Over a 7-year period, the wombat population declined 80% (95% CI 77-86%) and experienced a 55% range contraction. The average apparent prevalence of mange was high 27% (95% CI 21-34), increased slightly over our study period, and the population decline continued unabated, independent of declining host abundance. Combined with other longitudinal studies, our research indicated wombat populations may be at risk of decline when apparent prevalence exceeds 25%. This empirical study supports the capacity of environmentally transmitted parasites to cause density independent host population declines and suggests prevalence limits may be an indicator of impending decline-causing epizootics in bare-nosed wombats. This research is the first to test effects of density in mange epizootics where transmission is environmental and may provide a guide for when apparent prevalence indicates a local conservation threat.
Collapse
Affiliation(s)
- Scott Carver
- Department of Biological Sciences, University of Tasmania, Tasmania, Australia
| | - Zachary M. Lewin
- Department of Biological Sciences, University of Tasmania, Tasmania, Australia
| | - Leah G. Burgess
- Department of Biological Sciences, University of Tasmania, Tasmania, Australia
| | - Vicky Wilkinson
- Department of Biological Sciences, University of Tasmania, Tasmania, Australia
| | | | | |
Collapse
|
8
|
Zeng L, Li J, Lv M, Li Z, Yao L, Gao J, Wu Q, Wang Z, Yang X, Tang G, Qu G, Jiang G. Environmental Stability and Transmissibility of Enveloped Viruses at Varied Animate and Inanimate Interfaces. Environ Health (Wash) 2023; 1:15-31. [PMID: 37552709 PMCID: PMC10255587 DOI: 10.1021/envhealth.3c00005] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 08/10/2023]
Abstract
Enveloped viruses have been the leading causative agents of viral epidemics in the past decade, including the ongoing coronavirus disease 2019 outbreak. In epidemics caused by enveloped viruses, direct contact is a common route of infection, while indirect transmissions through the environment also contribute to the spread of the disease, although their significance remains controversial. Bridging the knowledge gap regarding the influence of interfacial interactions on the persistence of enveloped viruses in the environment reveals the transmission mechanisms when the virus undergoes mutations and prevents excessive disinfection during viral epidemics. Herein, from the perspective of the driving force, partition efficiency, and viral survivability at interfaces, we summarize the viral and environmental characteristics that affect the environmental transmission of viruses. We expect to provide insights for virus detection, environmental surveillance, and disinfection to limit the spread of severe acute respiratory syndrome coronavirus 2.
Collapse
Affiliation(s)
- Li Zeng
- State Key Laboratory of Environmental Chemistry and
Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of
Sciences, Beijing 100049, China
| | - Junya Li
- College of Sciences, Northeastern
University, Shenyang 110819, China
| | - Meilin Lv
- College of Sciences, Northeastern
University, Shenyang 110819, China
| | - Zikang Li
- State Key Laboratory of Environmental Chemistry and
Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of
Sciences, Beijing 100049, China
| | - Linlin Yao
- State Key Laboratory of Environmental Chemistry and
Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of
Sciences, Beijing 100049, China
| | - Jie Gao
- State Key Laboratory of Environmental Chemistry and
Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- School of Environment, Hangzhou Institute
for Advanced Study, UCAS, Hangzhou 310000, China
| | - Qi Wu
- State Key Laboratory of Environmental Chemistry and
Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- School of Environment, Hangzhou Institute
for Advanced Study, UCAS, Hangzhou 310000, China
| | - Ziniu Wang
- State Key Laboratory of Environmental Chemistry and
Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of
Sciences, Beijing 100049, China
| | - Xinyue Yang
- State Key Laboratory of Environmental Chemistry and
Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of
Sciences, Beijing 100049, China
| | - Gang Tang
- State Key Laboratory of Environmental Chemistry and
Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of
Sciences, Beijing 100049, China
| | - Guangbo Qu
- State Key Laboratory of Environmental Chemistry and
Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- School of Environment, Hangzhou Institute
for Advanced Study, UCAS, Hangzhou 310000, China
- Institute of Environment and Health,
Jianghan University, Wuhan 430056,
China
- University of Chinese Academy of
Sciences, Beijing 100049, China
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and
Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing 100085, China
- School of Environment, Hangzhou Institute
for Advanced Study, UCAS, Hangzhou 310000, China
- University of Chinese Academy of
Sciences, Beijing 100049, China
| |
Collapse
|
9
|
Crall V, Lewis C, Dickman D, Grinage D, George T, Ayres A, Ciccone C, Snyder G. Strategies for deployment of ultraviolet disinfection in an acute care facility: A quality improvement initiative. Am J Infect Control 2023:S0196-6553(23)00334-6. [PMID: 37116712 DOI: 10.1016/j.ajic.2023.04.164] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 04/16/2023] [Accepted: 04/17/2023] [Indexed: 04/30/2023]
Abstract
BACKGROUND Mobile ultraviolet (UV) disinfection uses UV-C light to render microorganisms nonviable and reduce environmental transmission of pathogens in hospital settings. Optimal strategies for deployment must consider cost, physical layout, and staffing resources. The aim of this quality improvement study was to increase UV disinfection utilization by developing novel deployment strategies without adding resources. METHODS A novel deployment strategy and tools were developed by a multidisciplinary group that included infection prevention, environmental services, and nursing unit staff. Utilization was tracked via a manufacturer-supported database. Infection prevention analyzed weekly UV disinfection minutes, cycles, and proportions of cycles completed in defined areas across four periods: baseline, pilot, baseline 2, and intervention. RESULTS The median (range) of disinfection cycle time per week during a geographically confined pilot (4,985 minutes [3,476-6,551 minutes]) and the intervention period (1,454 [512-3,085] minutes) were lower than either baseline period (5,394 [3,953-6,987] and 6,641 [2,830-7,276] minutes, respectively). Cycles per week were lower in the intervention period than the preceding three periods. CONCLUSIONS Use of UV disinfection in acute care settings should be guided by multidisciplinary groups balancing resources against efficacy and using tailored tools to promote efficiency.
Collapse
Affiliation(s)
- Victoria Crall
- Department of Infection Control and Hospital Epidemiology, UPMC Presbyterian-Shadyside, Pittsburgh, Pennsylvania, USA
| | - Casey Lewis
- Department of Infection Control and Hospital Epidemiology, UPMC Presbyterian-Shadyside, Pittsburgh, Pennsylvania, USA
| | - Daniel Dickman
- Department of Environmental Services, UPMC Presbyterian-Shadyside, Pittsburgh, Pennsylvania, USA
| | - Darnell Grinage
- Department of Environmental Services, UPMC Presbyterian-Shadyside, Pittsburgh, Pennsylvania, USA
| | - Trish George
- Department of Patient Safety and Innovation, UPMC Presbyterian-Shadyside, Pittsburgh, Pennsylvania, USA
| | - Ashley Ayres
- Department of Infection Control and Hospital Epidemiology, UPMC Presbyterian-Shadyside, Pittsburgh, Pennsylvania, USA
| | - Carl Ciccone
- Department of Infection Control and Hospital Epidemiology, UPMC Presbyterian-Shadyside, Pittsburgh, Pennsylvania, USA
| | - Graham Snyder
- Department of Infection Control and Hospital Epidemiology, UPMC Presbyterian-Shadyside, Pittsburgh, Pennsylvania, USA; Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
| |
Collapse
|
10
|
de Rooij MM, Sikkema RS, Bouwknegt M, de Geus Y, Stanoeva KR, Nieuwenweg S, van Dam AS, Raben C, Dohmen W, Heederik D, Reusken C, Meijer A, Koopmans MP, Franz E, Smit LA. A Comprehensive Sampling Study on SARS-CoV-2 Contamination of Air and Surfaces in a Large Meat Processing Plant Experiencing COVID-19 Clusters in June 2020. J Occup Environ Med 2023; 65:e227-e233. [PMID: 36640441 PMCID: PMC10090283 DOI: 10.1097/jom.0000000000002785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE We aimed to assess SARS-CoV-2 contamination of air and surfaces to gain insight into potential occupational exposure in a large meat processing plant experiencing COVID-19 clusters. Methods: Oro-nasopharyngeal SARS-CoV-2 screening was performed in 76 workers. Environmental samples ( n = 275) including air, ventilation systems, sewage, and swabs of high-touch surfaces and workers' hands were tested for SARS-CoV-2 RNA by real-time quantitative polymerase chain reaction. Results: Twenty-seven (35.5%) of the (predominantly asymptomatic) workers tested positive with modest to low viral loads (cycle threshold ≥ 29.7). Six of 203 surface swabs, 1 of 12 personal air samples, and one of four sewage samples tested positive; other samples tested negative. Conclusions: Although one third of workers tested positive, environmental contamination was limited. Widespread SARS-CoV-2 transmission via air and surfaces was considered unlikely within this plant at the time of investigation while strict COVID-19 control measures were already implemented.
Collapse
|
11
|
Jin Y, Cui H, Jiang L, Zhang C, Li J, Cheng H, Chen Z, Zheng J, Zhang Y, Fu Y, Li J, Li L, Guo Z, Lu B, Wang Z. Evidence for human infection with avian influenza A(H9N2) virus via environmental transmission inside live poultry market in Xiamen, China. J Med Virol 2023; 95:e28242. [PMID: 36261874 DOI: 10.1002/jmv.28242] [Citation(s) in RCA: 3] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/09/2022] [Accepted: 10/17/2022] [Indexed: 01/11/2023]
Abstract
H9N2 avian influenza virus (AIV) has become prevalent in the live poultry market (LPM) worldwide, and environmental transmission mode is an important way for AIVs to infect human beings in the LPM. To find evidence of human infection with the influenza A(H9N2) virus via environmental contamination, we evaluated one human isolate and three environmental isolates inside LPMs in Xiamen, China. The phylogeny, transmissibility, and pathogenicity of the four isolates were sorted out systematically. As for the H9N2 virus, which evolved alongside the "Avian-Environment-Human" spreading chain in LPMs from the summer of 2019 to the summer of 2020, its overall efficiency of contact and aerosol transmissibility improved, which might contribute to the increasing probability of human infection. This study indicated that environmental exposure might act as an important source of human infection in LPMs.
Collapse
Affiliation(s)
- Yifei Jin
- Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Huan Cui
- Changchun Veterinary Research Institute, Chinese Academy of Agriculture Sciences, Changchun, China
| | - Lina Jiang
- Xiamen Center for Disease Control and Prevention, Xiamen, China
| | - Cheng Zhang
- Changchun Veterinary Research Institute, Chinese Academy of Agriculture Sciences, Changchun, China
| | - Jingjing Li
- Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Hongliang Cheng
- Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Zehui Chen
- Xiamen Center for Disease Control and Prevention, Xiamen, China
| | - Jing Zheng
- Xiamen Center for Disease Control and Prevention, Xiamen, China
| | - Yidun Zhang
- Xiamen Center for Disease Control and Prevention, Xiamen, China
| | - Yingying Fu
- Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Jiaming Li
- Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Li Li
- Xiamen Center for Disease Control and Prevention, Xiamen, China
| | - Zhendong Guo
- Changchun Veterinary Research Institute, Chinese Academy of Agriculture Sciences, Changchun, China
| | - Bing Lu
- Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Zhongyi Wang
- Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| |
Collapse
|
12
|
Hindle IJ, Forbes LK, Carver S. The effect of spatial dynamics on the behaviour of an environmentally transmitted disease. J Biol Dyn 2022; 16:144-159. [PMID: 35404769 DOI: 10.1080/17513758.2022.2061614] [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] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 03/14/2022] [Indexed: 06/14/2023]
Abstract
Understanding the spread of pathogens through the environment is critical to a fuller comprehension of disease dynamics. However, many mathematical models of disease dynamics ignore spatial effects. We seek to expand knowledge around the interaction between the bare-nosed wombat (Vombatus ursinus) and sarcoptic mange (etiologic agent Sarcoptes scabiei), by extending an aspatial mathematical model to include spatial variation. S. scabiei was found to move through our modelled region as a spatio-temporal travelling wave, leaving behind pockets of localized host extinction, consistent with field observations. The speed of infection spread was also comparable with field research. Our model predicts that the inclusion of spatial dynamics leads to the survival and recovery of affected wombat populations when an aspatial model predicts extinction. Collectively, this research demonstrates how environmentally transmitted S. scabiei can result in travelling wave dynamics, and that inclusion of spatial variation reveals a more resilient host population than aspatial modelling approaches.
Collapse
Affiliation(s)
- Ivy J Hindle
- School of Physical Sciences, University of Tasmania, Hobart, Australia
| | - Lawrence K Forbes
- School of Physical Sciences, University of Tasmania, Hobart, Australia
| | - Scott Carver
- Department of Biological Sciences, University of Tasmania, Hobart, Australia
| |
Collapse
|
13
|
Jinatham V, Maxamhud S, Popluechai S, Tsaousis AD, Gentekaki E. Blastocystis One Health Approach in a Rural Community of Northern Thailand: Prevalence, Subtypes and Novel Transmission Routes. Front Microbiol 2021; 12:746340. [PMID: 34956115 PMCID: PMC8696170 DOI: 10.3389/fmicb.2021.746340] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [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: 07/23/2021] [Accepted: 11/16/2021] [Indexed: 12/12/2022] Open
Abstract
Blastocystis is the most commonly found eukaryote in the gut of humans and other animals. This protist is extremely heterogeneous genetically and is classified into 28 subtypes (STs) based on the small subunit ribosomal RNA (SSU rRNA) gene. Numerous studies exist on prevalence of the organism, which usually focus on either humans or animals or the environment, while only a handful investigates all three sources simultaneously. Consequently, understanding of Blastocystis transmission dynamics remains inadequate. Our aim was to explore Blastocystis under the One Health perspective using a rural community in northern Thailand as our study area. We surveyed human, other animal and environmental samples using both morphological and molecular approaches. Prevalence rates of Blastocystis were 73% in human hosts (n = 45), 100% in non-human hosts (n = 44) and 91% in environmental samples (n = 35). Overall, ten subtypes were identified (ST1, ST2, ST3, ST4 ST5, ST6, ST7, ST10, ST23, and ST26), eight of which were detected in humans (ST1, ST2, ST3, ST4, ST5, ST7, ST10, and ST23), three in other animals (ST6, ST7, and ST23), while seven (ST1, ST3, ST6, ST7, ST10, ST23, and ST26) were found in the environment. In our investigation of transmission dynamics, we assessed various groupings both at the household and community level. Given the overall high prevalence rate, transmission amongst humans and between animals and humans are not as frequent as expected with only two subtypes being shared. This raises questions on the role of the environment on transmission of Blastocystis. Water and soil comprise the main reservoirs of the various subtypes in this community. Five subtypes are shared between humans and the environment, while three overlap between the latter and animal hosts. We propose soil as a novel route of transmission, which should be considered in future investigations. This study provides a thorough One Health perspective on Blastocystis. Using this type of approach advances our understanding on occurrence, diversity, ecology and transmission dynamics of this poorly understood, yet frequent gut resident.
Collapse
Affiliation(s)
- Vasana Jinatham
- School of Science, Mae Fah Luang University, Chiang Rai, Thailand
| | - Sadiya Maxamhud
- Laboratory of Molecular and Evolutionary Parasitology, RAPID Group, School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Siam Popluechai
- School of Science, Mae Fah Luang University, Chiang Rai, Thailand.,Gut Microbiome Research Group, Mae Fah Luang University, Chiang Rai, Thailand
| | - Anastasios D Tsaousis
- Laboratory of Molecular and Evolutionary Parasitology, RAPID Group, School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Eleni Gentekaki
- School of Science, Mae Fah Luang University, Chiang Rai, Thailand.,Gut Microbiome Research Group, Mae Fah Luang University, Chiang Rai, Thailand
| |
Collapse
|
14
|
Abstract
Prions are proteinaceous infectious agents that can be transmitted through various components of the environment, including soil particles. We found that earthworms exposed to prion-contaminated soil can bind, retain, and excrete prions, which remain highly infectious. Our results suggest that earthworms potentially contribute to prion disease spread in the environment.
Collapse
|
15
|
Gauld JS, Olgemoeller F, Heinz E, Nkhata R, Bilima S, Wailan AM, Kennedy N, Mallewa J, Gordon MA, Read JM, Heyderman RS, Thomson NR, Diggle PJ, Feasey NA. Spatial and Genomic Data to Characterize Endemic Typhoid Transmission. Clin Infect Dis 2021; 74:1993-2000. [PMID: 34463736 PMCID: PMC9187325 DOI: 10.1093/cid/ciab745] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Diverse environmental exposures and risk factors have been implicated in the transmission of Salmonella Typhi, but the dominant transmission pathways through the environment to susceptible humans remain unknown. Here, we use spatial, bacterial genomic, and hydrological data to refine our view of typhoid transmission in an endemic setting. METHODS A total of 546 patients presenting to Queen Elizabeth Central Hospital in Blantyre, Malawi, with blood culture-confirmed typhoid fever between April 2015 and January 2017 were recruited to a cohort study. The households of a subset of these patients were geolocated, and 256 S. Typhi isolates were whole-genome sequenced. Pairwise single-nucleotide variant distances were incorporated into a geostatistical modeling framework using multidimensional scaling. RESULTS Typhoid fever was not evenly distributed across Blantyre, with estimated minimum incidence ranging across the city from <15 to >100 cases per 100 000 population per year. Pairwise single-nucleotide variant distance and physical household distances were significantly correlated (P = .001). We evaluated the ability of river catchment to explain the spatial patterns of genomics observed, finding that it significantly improved the fit of the model (P = .003). We also found spatial correlation at a smaller spatial scale, of households living <192 m apart. CONCLUSIONS These findings reinforce the emerging view that hydrological systems play a key role in the transmission of typhoid fever. By combining genomic and spatial data, we show how multifaceted data can be used to identify high incidence areas, explain the connections between them, and inform targeted environmental surveillance, all of which will be critical to shape local and regional typhoid control strategies.
Collapse
Affiliation(s)
- Jillian S Gauld
- Correspondence: Jillian S. Gauld, Institute for Disease Modeling, Bill and Melinda Gates Foundation, 500 Fifth Ave N, Seattle WA 98109 ()
| | - Franziska Olgemoeller
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom,Malawi-Liverpool Wellcome Programme, Blantyre, Malawi
| | - Eva Heinz
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom,Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Rose Nkhata
- Malawi-Liverpool Wellcome Programme, Blantyre, Malawi
| | | | | | - Neil Kennedy
- Department of Paediatrics, University of Malawi the College of Medicine, Blantyre, Malawi,School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Jane Mallewa
- Adult Medicine, University of Malawi the College of Medicine, Blantyre, Malawi
| | - Melita A Gordon
- Malawi-Liverpool Wellcome Programme, Blantyre, Malawi,Institute of Infection, Veterinary and Ecological Sciences, The University of Liverpool, Liverpool, United Kingdom,Adult Medicine, University of Malawi the College of Medicine, Blantyre, Malawi
| | - Jonathan M Read
- Centre for Health Informatics, Computing, and Statistics, Lancaster University, Lancaster, United Kingdom
| | - Robert S Heyderman
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Nicholas R Thomson
- Wellcome Sanger Institute, Cambridge, United Kingdom,Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Peter J Diggle
- Centre for Health Informatics, Computing, and Statistics, Lancaster University, Lancaster, United Kingdom
| | - Nicholas A Feasey
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom,Malawi-Liverpool Wellcome Programme, Blantyre, Malawi
| |
Collapse
|
16
|
Beerens N, Germeraad EA, Venema S, Verheij E, Pritz-Verschuren SBE, Gonzales JL. Comparative pathogenicity and environmental transmission of recent highly pathogenic avian influenza H5 viruses. Emerg Microbes Infect 2021; 10:97-108. [PMID: 33350337 PMCID: PMC7832006 DOI: 10.1080/22221751.2020.1868274] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [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] [Indexed: 12/14/2022]
Abstract
Strategies to control spread of highly pathogenic avian influenza (HPAI) viruses by wild birds appear limited, hence timely characterization of novel viruses is important to mitigate the risk for the poultry sector and human health. In this study we characterize three recent H5-clade 2.3.4.4 viruses, the H5N8-2014 group A virus and the H5N8-2016 and H5N6-2017 group B viruses. The pathogenicity of the three viruses for chickens, Pekin ducks and Eurasian wigeons was compared. The three viruses were highly pathogenic for chickens, but the two H5N8 viruses caused no to mild clinical symptoms in both duck species. The highest pathogenicity for duck species was observed for the most recent H5N6-2017 virus. For both duck species, virus shedding from the cloaca was higher after infection with group B viruses compared to the H5N8-2014 group A virus. Higher cloacal virus shedding of wild ducks may increase transmission between wild birds and poultry. Environmental transmission of H5N8-2016 virus to chickens was studied, which showed that chickens are efficiently infected by (fecal) contaminated water. These results suggest that pathogenicity of HPAI H5 viruses and virus shedding for ducks is evolving, which may have implications for the risk of introduction of these viruses into the poultry sector.
Collapse
Affiliation(s)
- Nancy Beerens
- Wageningen University and Research - Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Evelien A Germeraad
- Wageningen University and Research - Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Sandra Venema
- Wageningen University and Research - Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Eline Verheij
- Wageningen University and Research - Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | | | - Jose L Gonzales
- Wageningen University and Research - Wageningen Bioveterinary Research, Lelystad, The Netherlands
| |
Collapse
|
17
|
Bell-Dereske LP, Evans SE. Contributions of environmental and maternal transmission to the assembly of leaf fungal endophyte communities. Proc Biol Sci 2021; 288:20210621. [PMID: 34375558 DOI: 10.1098/rspb.2021.0621] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Leaf fungal endophytes (LFEs) contribute to plant growth and responses to stress. Fungi colonize leaves through maternal transmission, e.g. via the seed, and through environmental transmission, e.g. via aerial dispersal. The relative importance of these two pathways in assembly and function of the LFE community is poorly understood. We used amplicon sequencing to track switchgrass (Panicum virgatum) LFEs in a greenhouse and field experiment as communities assembled from seed endophytes and rain fungi (integration of wet and dry aerial dispersal) in germinating seeds, seedlings, and adult plants. Rain fungi varied temporally and hosted a greater portion of switchgrass LFE richness (greater than 65%) than were found in seed endophytes (greater than 25%). Exposure of germinating seeds to rain inoculum increased dissimilarity between LFE communities and seed endophytes, increasing the abundance of rain-derived taxa, but did not change diversity. In the field, seedling LFE composition changed more over time, with a decline in seed-derived taxa and an increase in richness, in response to environmental transmission than LFEs of adult plants. We show that environmental transmission is an important driver of LFE assembly, and likely plant growth, but its influence depends on both the conditions at the time of colonization and plant life stage.
Collapse
Affiliation(s)
- Lukas P Bell-Dereske
- Laboratory of Environmental Microbiology, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Sarah E Evans
- W.K. Kellogg Biological Station, Michigan State University, Hickory Corners, MI 49060, USA.,Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA.,Ecology and Evolutionary Biology Program, Michigan State University, East Lansing, MI 48824, USA
| |
Collapse
|
18
|
Dawson D, Rasmussen D, Peng X, Lanzas C. Inferring environmental transmission using phylodynamics: a case-study using simulated evolution of an enteric pathogen. J R Soc Interface 2021; 18:20210041. [PMID: 34102084 DOI: 10.1098/rsif.2021.0041] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Indirect (environmental) and direct (host-host) transmission pathways cannot easily be distinguished when they co-occur in epidemics, particularly when they occur on similar time scales. Phylodynamic reconstruction is a potential approach to this problem that combines epidemiological information (temporal, spatial information) with pathogen whole-genome sequencing data to infer transmission trees of epidemics. However, factors such as differences in mutation and transmission rates between host and non-host environments may obscure phylogenetic inference from these methods. In this study, we used a network-based transmission model that explicitly models pathogen evolution to simulate epidemics with both direct and indirect transmission. Epidemics were simulated according to factorial combinations of direct/indirect transmission proportions, host mutation rates and conditions of environmental pathogen growth. Transmission trees were then reconstructed using the phylodynamic approach SCOTTI (structured coalescent transmission tree inference) and evaluated. We found that although insufficient diversity sets a lower bound on when accurate phylodynamic inferences can be made, transmission routes and assumed pathogen lifestyle affected pathogen population structure and subsequently influenced both reconstruction success and the likelihood of direct versus indirect pathways being reconstructed. We conclude that prior knowledge of the likely ecology and population structure of pathogens in host and non-host environments is critical to fully using phylodynamic techniques.
Collapse
Affiliation(s)
- Daniel Dawson
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - David Rasmussen
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA.,Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA
| | - Xinxia Peng
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA.,Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Cristina Lanzas
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| |
Collapse
|
19
|
Huang YH, Joel H, Küsters M, Barandongo ZR, Cloete CC, Hartmann A, Kamath PL, Kilian JW, Mfune JKE, Shatumbu G, Zidon R, Getz WM, Turner WC. Disease or drought: environmental fluctuations release zebra from a potential pathogen-triggered ecological trap. Proc Biol Sci 2021; 288:20210582. [PMID: 34074118 PMCID: PMC8170208 DOI: 10.1098/rspb.2021.0582] [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] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/10/2021] [Indexed: 12/02/2022] Open
Abstract
When a transmission hotspot for an environmentally persistent pathogen establishes in otherwise high-quality habitat, the disease may exert a strong impact on a host population. However, fluctuating environmental conditions lead to heterogeneity in habitat quality and animal habitat preference, which may interrupt the overlap between selected and risky habitats. We evaluated spatio-temporal patterns in anthrax mortalities in a plains zebra (Equus quagga) population in Etosha National Park, Namibia, incorporating remote-sensing and host telemetry data. A higher proportion of anthrax mortalities of herbivores was detected in open habitats than in other habitat types. Resource selection functions showed that the zebra population shifted habitat selection in response to changes in rainfall and vegetation productivity. Average to high rainfall years supported larger anthrax outbreaks, with animals congregating in preferred open habitats, while a severe drought forced animals into otherwise less preferred habitats, leading to few anthrax mortalities. Thus, the timing of anthrax outbreaks was congruent with preference for open plains habitats and a corresponding increase in pathogen exposure. Given shifts in habitat preference, the overlap in high-quality habitat and high-risk habitat is intermittent, reducing the adverse consequences for the population.
Collapse
Affiliation(s)
- Yen-Hua Huang
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Hendrina Joel
- Department of Biological Sciences, University of Namibia, Windhoek, Namibia
| | | | - Zoe R. Barandongo
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Claudine C. Cloete
- Etosha Ecological Institute, Ministry of Environment, Forestry and Tourism, Okaukuejo, Namibia
| | - Axel Hartmann
- Etosha Ecological Institute, Ministry of Environment, Forestry and Tourism, Okaukuejo, Namibia
| | - Pauline L. Kamath
- School of Food and Agriculture, University of Maine, Orono, ME 04469, USA
| | - J. Werner Kilian
- Etosha Ecological Institute, Ministry of Environment, Forestry and Tourism, Okaukuejo, Namibia
| | - John K. E. Mfune
- Department of Biological Sciences, University of Namibia, Windhoek, Namibia
| | - Gabriel Shatumbu
- Etosha Ecological Institute, Ministry of Environment, Forestry and Tourism, Okaukuejo, Namibia
| | - Royi Zidon
- Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Wayne M. Getz
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94704, USA
- School of Mathematical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Wendy C. Turner
- US Geological Survey, Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
| |
Collapse
|
20
|
Cortez MH, Duffy MA. The Context-Dependent Effects of Host Competence, Competition, and Pathogen Transmission Mode on Disease Prevalence. Am Nat 2021; 198:179-194. [PMID: 34260871 DOI: 10.1086/715110] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractBiodiversity in communities is changing globally, including the gain and loss of host species in host-pathogen communities. Increased host diversity can cause infection prevalence in a focal host to increase (amplification) or decrease (dilution). However, it is unclear what general rules govern the context-dependent effects, in part because theories for pathogens with different transmission modes have developed largely independently. Using a two-host model, we explore how the pathogen transmission mode and characteristics of a second host (disease competence and competitive ability) influence disease prevalence in a focal host. Our work shows how the theories for pathogens with environmental transmission, density-dependent direct transmission, and frequency-dependent direct transmission can be unified. Our work also identifies general rules about how host and pathogen characteristics affect amplification/dilution. For example, higher-competence hosts promote amplification, unless they are strong interspecific competitors; strong interspecific competitors promote dilution, unless they are large sources of new infections; and dilution occurs under frequency-dependent direct transmission more than density-dependent direct transmission, unless interspecific host competition is sufficiently strong. Our work helps explain how the characteristics of the pathogen and a second host affect disease prevalence in a focal host.
Collapse
|
21
|
Mulder AC, van de Kassteele J, Heederik D, Pijnacker R, Mughini‐Gras L, Franz E. Spatial Effects of Livestock Farming on Human Infections With Shiga Toxin-Producing Escherichia coli O157 in Small but Densely Populated Regions: The Case of the Netherlands. Geohealth 2020; 4:e2020GH000276. [PMID: 33283126 PMCID: PMC7682566 DOI: 10.1029/2020gh000276] [Citation(s) in RCA: 4] [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] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/26/2020] [Accepted: 09/28/2020] [Indexed: 06/12/2023]
Abstract
The role of environmental transmission of typically foodborne pathogens like Shiga toxin-producing Escherichia coli (STEC) O157 is increasingly recognized. To gain more insights into spatially restricted risk factors that play a role in this transmission, we assessed the spatial association between sporadic STEC O157 human infections and the exposure to livestock (i.e. small ruminants, cattle, poultry, and pigs) in a densely populated country: the Netherlands. This was done for the years 2007-2016, using a state-of-the-art spatial analysis method in which hexagonal areas with different sizes (90, 50, 25 and 10 km2) were used in combination with a novel probability of exposure metric: the population-weighted number of animals per hexagon. To identify risk factors for STEC O157 infections and their population attributable fraction (PAF), a spatial regression model was fitted using integrated nested Laplace approximation (INLA). Living in hexagonal areas of 25, 50 and 90 km2 with twice as much population-weighted small ruminants was associated with an increase of the incidence rate of human STEC O157 infections in summer (RR of 1.09 [95%CI;1.01-1.17], RR of 1.17 [95%CI;1.07-1.28] and RR of 1.13 [95%CI;1.01-1.26]), with a PAF of 49% (95%CI;8-72%). Results suggest exposure to small ruminants to be a risk factor, although no evidence on the mode of transmission is provided. Therefore, the underlying mechanisms warrant further investigation and could offer new targets for control. The newly proposed exposure metric has potential to improve existing spatial modeling studies on infectious diseases related to livestock exposure, especially in densely populated countries like the Netherlands.
Collapse
Affiliation(s)
- A. C. Mulder
- Centre for Infectious Disease ControlNational Institute for Public Health and the Environment (RIVM)Bilthoventhe Netherlands
| | - J. van de Kassteele
- Centre for Infectious Disease ControlNational Institute for Public Health and the Environment (RIVM)Bilthoventhe Netherlands
| | - D. Heederik
- Institute for Risk Assessment Sciences (IRAS), Division of Environmental EpidemiologyUtrecht UniversityUtrechtthe Netherlands
| | - R. Pijnacker
- Centre for Infectious Disease ControlNational Institute for Public Health and the Environment (RIVM)Bilthoventhe Netherlands
| | - L. Mughini‐Gras
- Centre for Infectious Disease ControlNational Institute for Public Health and the Environment (RIVM)Bilthoventhe Netherlands
- Institute for Risk Assessment Sciences (IRAS), Division of Environmental EpidemiologyUtrecht UniversityUtrechtthe Netherlands
| | - E. Franz
- Centre for Infectious Disease ControlNational Institute for Public Health and the Environment (RIVM)Bilthoventhe Netherlands
| |
Collapse
|
22
|
Cabezas AH, Sanderson MW, Volkova VV. A Meta-Population Model of Potential Foot-and-Mouth Disease Transmission, Clinical Manifestation, and Detection Within U.S. Beef Feedlots. Front Vet Sci 2020; 7:527558. [PMID: 33195510 PMCID: PMC7543087 DOI: 10.3389/fvets.2020.527558] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 01/16/2020] [Accepted: 08/24/2020] [Indexed: 11/13/2022] Open
Abstract
Foot-and-mouth disease (FMD) has not been reported in the U.S. since 1929. Recent outbreaks in previously FMD-free countries raise concerns about potential FMD introductions in the U.S. Mathematical modeling is the only tool for simulating infectious disease outbreaks in non-endemic territories. In the majority of prior studies, FMD virus (FMDv) transmission on-farm was modeled assuming homogenous animal mixing. This assumption is implausible for U.S. beef feedlots which are divided into multiple home-pens without contact between home-pens except fence line with contiguous home-pens and limited mixing in hospital pens. To project FMDv transmission and clinical manifestation in a feedlot, we developed a meta-population stochastic model reflecting the contact structure. Within a home-pen, the dynamics were represented assuming homogenous animal mixing by a modified SLIR (susceptible-latent-infectious-recovered) model with four additional compartments tracing cattle with subclinical or clinical FMD and infectious status. Virus transmission among home-pens occurred via cattle mixing in hospital-pen(s), cowboy pen rider movements between home-pens, airborne, and for contiguous home-pens fence-line and via shared water-troughs. We modeled feedlots with a one-time capacity of 4,000 (small), 12,000 (medium), and 24,000 (large) cattle. Common cattle demographics, feedlot layout, endemic infectious and non-infectious disease occurrence, and production management were reflected. Projected FMD-outbreak duration on a feedlot ranged from 49 to 82 days. Outbreak peak day (with maximum number of FMD clinical cattle) ranged from 24 (small) to 49 (large feedlot). Detection day was 4-12 post-FMD-introduction with projected 28, 9, or 4% of cattle already infected in a small, medium, or large feedlot, respectively. Depletion of susceptible cattle in a feedlot occurred by day 23-51 post-FMD-introduction. Parameter-value sensitivity analyses were performed for model outputs. Detection occurred sooner if there was a higher initial proportion of latent animals in the index home-pen. Shorter outbreaks were associated with a shorter latent period and higher bovine respiratory disease morbidity (impacting the in-hospital-pen cattle mixing occurrence). This first model of potential FMD dynamics on U.S. beef feedlots shows the importance of capturing within-feedlot cattle contact structure for projecting infectious disease dynamics. Our model provides a tool for evaluating FMD outbreak control strategies.
Collapse
Affiliation(s)
- Aurelio H Cabezas
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States.,Center for Outcomes Research and Epidemiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Michael W Sanderson
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States.,Center for Outcomes Research and Epidemiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Victoriya V Volkova
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States.,Center for Outcomes Research and Epidemiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| |
Collapse
|
23
|
Kim JS, Lee MS, Kim JH. Recent Updates on Outbreaks of Shiga Toxin-Producing Escherichia coli and Its Potential Reservoirs. Front Cell Infect Microbiol 2020; 10:273. [PMID: 32582571 PMCID: PMC7287036 DOI: 10.3389/fcimb.2020.00273] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [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: 01/29/2020] [Accepted: 05/07/2020] [Indexed: 12/30/2022] Open
Abstract
Following infection with certain strains of Shiga toxin-producing Escherichia coli (STEC), particularly enterohemorrhagic ones, patients are at elevated risk for developing life-threatening extraintestinal complications, such as acute renal failure. Hence, these bacteria represent a public health concern in both developed and developing countries. Shiga toxins (Stxs) expressed by STEC are highly cytotoxic class II ribosome-inactivating proteins and primary virulence factors responsible for major clinical signs of Stx-mediated pathogenesis, including bloody diarrhea, hemolytic uremic syndrome (HUS), and neurological complications. Ruminant animals are thought to serve as critical environmental reservoirs of Stx-producing Escherichia coli (STEC), but other emerging or arising reservoirs of the toxin-producing bacteria have been overlooked. In particular, a number of new animal species from wildlife and aquaculture industries have recently been identified as unexpected reservoir or spillover hosts of STEC. Here, we summarize recent findings about reservoirs of STEC and review outbreaks of these bacteria both within and outside the United States. A better understanding of environmental transmission to humans will facilitate the development of novel strategies for preventing zoonotic STEC infection.
Collapse
Affiliation(s)
- Jun-Seob Kim
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Moo-Seung Lee
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, South Korea.,Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Ji Hyung Kim
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, South Korea
| |
Collapse
|
24
|
Pepin KM, Golnar AJ, Abdo Z, Podgórski T. Ecological drivers of African swine fever virus persistence in wild boar populations: Insight for control. Ecol Evol 2020; 10:2846-2859. [PMID: 32211160 PMCID: PMC7083705 DOI: 10.1002/ece3.6100] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [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] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 01/12/2020] [Indexed: 12/12/2022] Open
Abstract
Environmental sources of infection can play a primary role in shaping epidemiological dynamics; however, the relative impact of environmental transmission on host-pathogen systems is rarely estimated. We developed and fit a spatially explicit model of African swine fever virus (ASFV) in wild boar to estimate what proportion of carcass-based transmission is contributing to the low-level persistence of ASFV in Eastern European wild boar. Our model was developed based on ecological insight and data from field studies of ASFV and wild boar in Eastern Poland. We predicted that carcass-based transmission would play a substantial role in persistence, especially in low-density host populations where contact rates are low. By fitting the model to outbreak data using approximate Bayesian computation, we inferred that between 53% and 66% of transmission events were carcass-based that is, transmitted through contact of a live host with a contaminated carcass. Model fitting and sensitivity analyses showed that the frequency of carcass-based transmission increased with decreasing host density, suggesting that management policies should emphasize the removal of carcasses and consider how reductions in host densities may drive carcass-based transmission. Sensitivity analyses also demonstrated that carcass-based transmission is necessary for the autonomous persistence of ASFV under realistic parameters. Autonomous persistence through direct transmission alone required high host densities; otherwise re-introduction of virus periodically was required for persistence when direct transmission probabilities were moderately high. We quantify the relative role of different persistence mechanisms for a low-prevalence disease using readily collected ecological data and viral surveillance data. Understanding how the frequency of different transmission mechanisms vary across host densities can help identify optimal management strategies across changing ecological conditions.
Collapse
Affiliation(s)
- Kim M. Pepin
- National Wildlife Research CenterUSDAAPHISFort CollinsCOUSA
| | | | - Zaid Abdo
- Microbiology, Immunology, and PathologyColorado State UniversityFort CollinsCOUSA
| | - Tomasz Podgórski
- Mammal Research InstitutePolish Academy of SciencesBiałowieżaPoland
- Department of Game Management and Wildlife BiologyFaculty of Forestry and Wood SciencesCzech University of Life SciencesPraha 6Czech Republic
| |
Collapse
|
25
|
Abstract
Many pathogens are able to replicate or survive in abiotic environments. Disease transmission models that include environmental reservoirs and environment-to-host transmission have used a variety of functional forms and modelling frameworks without a clear connection to pathogen ecology or space and time scales. We present a conceptual framework to organize microparasites based on the role that abiotic environments play in their lifecycle. Mean-field and individual-based models for environmental transmission are analysed and compared. We show considerable divergence between both modelling approaches when conditions do not facilitate well mixing and for pathogens with fast dynamics in the environment. We conclude with recommendations for modelling environmentally transmitted pathogens based on the pathogen lifecycle and time and spatial scales of the host-pathogen system under consideration.
Collapse
Affiliation(s)
- Cristina Lanzas
- Department of Population Health and Pathobiology, North Carolina State University, Raleigh, NC, USA
| | | | | | | |
Collapse
|
26
|
Munck N, Smith J, Bates J, Glass K, Hald T, Kirk MD. Source Attribution of Salmonella in Macadamia Nuts to Animal and Environmental Reservoirs in Queensland, Australia. Foodborne Pathog Dis 2019; 17:357-364. [PMID: 31804848 PMCID: PMC7232652 DOI: 10.1089/fpd.2019.2706] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [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: 11/13/2022] Open
Abstract
Salmonella enterica is a common contaminant of macadamia nut kernels in the subtropical state of Queensland (QLD), Australia. We hypothesized that nonhuman sources in the plantation environment contaminate macadamia nuts. We applied a modified Hald source attribution model to attribute Salmonella serovars and phage types detected on macadamia nuts from 1998 to 2017 to specific animal and environmental sources. Potential sources were represented by Salmonella types isolated from avian, companion animal, biosolids-soil-compost, equine, porcine, poultry, reptile, ruminant, and wildlife samples by the QLD Health reference laboratory. Two attribution models were applied: model 1 merged data across 1998-2017, whereas model 2 pooled data into 5-year time intervals. Model 1 attributed 47% (credible interval, CrI: 33.6-60.8) of all Salmonella detections on macadamia nuts to biosolids-soil-compost. Wildlife and companion animals were found to be the second and third most important contamination sources, respectively. Results from model 2 showed that the importance of the different sources varied between the different time periods; for example, Salmonella contamination from biosolids-soil-compost varied from 4.4% (CrI: 0.2-11.7) in 1998-2002 to 19.3% (CrI: 4.6-39.4) in 2003-2007, and the proportion attributed to poultry varied from 4.8% (CrI: 1-11) in 2008-2012 to 24% (CrI: 11.3-40.7) in 2013-2017. Findings suggest that macadamia nuts were contaminated by direct transmission from animals with access to the plantations (e.g., wildlife and companion animals) or from indirect transmission from animal reservoirs through biosolids-soil-compost. The findings from this study can be used to guide environmental and wildlife sampling and analysis to further investigate routes of Salmonella contamination of macadamia nuts and propose control options to reduce potential risk of human salmonellosis.
Collapse
Affiliation(s)
- Nanna Munck
- Research Group for Genomic Epidemiology, National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - James Smith
- Food Safety Standards and Regulation, Health Protection Branch, Department of Health, Queensland Health, Brisbane, Australia
| | - John Bates
- Public Health Microbiology, Public & Environmental Health, Forensic and Scientific Services, Health Support Queensland, Department of Health, Brisbane, Australia
| | - Kathryn Glass
- National Centre for Epidemiology and Population Health, Research School of Population Health, Australian National University, Canberra, Australia
| | - Tine Hald
- Research Group for Genomic Epidemiology, National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Martyn D Kirk
- National Centre for Epidemiology and Population Health, Research School of Population Health, Australian National University, Canberra, Australia
| |
Collapse
|
27
|
Pepin KM, Hopken MW, Shriner SA, Spackman E, Abdo Z, Parrish C, Riley S, Lloyd-Smith JO, Piaggio AJ. Improving risk assessment of the emergence of novel influenza A viruses by incorporating environmental surveillance. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180346. [PMID: 31401963 PMCID: PMC6711309 DOI: 10.1098/rstb.2018.0346] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [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] [Indexed: 12/20/2022] Open
Abstract
Reassortment is an evolutionary mechanism by which influenza A viruses (IAV) generate genetic novelty. Reassortment is an important driver of host jumps and is widespread according to retrospective surveillance studies. However, predicting the epidemiological risk of reassortant emergence in novel hosts from surveillance data remains challenging. IAV strains persist and co-occur in the environment, promoting co-infection during environmental transmission. These conditions offer opportunity to understand reassortant emergence in reservoir and spillover hosts. Specifically, environmental RNA could provide rich information for understanding the evolutionary ecology of segmented viruses, and transform our ability to quantify epidemiological risk to spillover hosts. However, significant challenges with recovering and interpreting genomic RNA from the environment have impeded progress towards predicting reassortant emergence from environmental surveillance data. We discuss how the fields of genomics, experimental ecology and epidemiological modelling are well positioned to address these challenges. Coupling quantitative disease models and natural transmission studies with new molecular technologies, such as deep-mutational scanning and single-virus sequencing of environmental samples, should dramatically improve our understanding of viral co-occurrence and reassortment. We define observable risk metrics for emerging molecular technologies and propose a conceptual research framework for improving accuracy and efficiency of risk prediction. This article is part of the theme issue 'Dynamic and integrative approaches to understanding pathogen spillover'.
Collapse
Affiliation(s)
- Kim M. Pepin
- National Wildlife Research Center, USDA-APHIS, Fort Collins, CO 80521, USA
- e-mail:
| | - Matthew W. Hopken
- National Wildlife Research Center, USDA-APHIS, Fort Collins, CO 80521, USA
- Colorado State University, Fort Collins, CO 80523, USA
| | - Susan A. Shriner
- National Wildlife Research Center, USDA-APHIS, Fort Collins, CO 80521, USA
| | - Erica Spackman
- Exotic and Emerging Avian Viral Diseases Research, USDA-ARS, Athens, GA 30605, USA
| | - Zaid Abdo
- Colorado State University, Fort Collins, CO 80523, USA
| | - Colin Parrish
- Baker Institute for Animal Health, Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Steven Riley
- MRC Centre for Global Infectious Disease Analysis, Imperial College, London, SW7 2AZ, UK
| | - James O. Lloyd-Smith
- UCLA, Los Angeles, CA 90095, USA
- Department of Ecology and Evolutionary Biology, Fogarty International Center, National Institutes of Health, Bethesda MD 20892, USA
| | | |
Collapse
|
28
|
Majewska AA, Sims S, Schneider A, Altizer S, Hall RJ. Multiple transmission routes sustain high prevalence of a virulent parasite in a butterfly host. Proc Biol Sci 2019; 286:20191630. [PMID: 31480975 PMCID: PMC6742984 DOI: 10.1098/rspb.2019.1630] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [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: 01/19/2023] Open
Abstract
Understanding factors that allow highly virulent parasites to reach high infection prevalence in host populations is important for managing infection risks to human and wildlife health. Multiple transmission routes have been proposed as one mechanism by which virulent pathogens can achieve high prevalence, underscoring the need to investigate this hypothesis through an integrated modelling-empirical framework. Here, we examine a harmful specialist protozoan infecting monarch butterflies that commonly reaches high prevalence (50–100%) in resident populations. We integrate field and modelling work to show that a combination of three empirically-supported transmission routes (vertical, adult transfer and environmental transmission) can produce and sustain high infection prevalence in this system. Although horizontal transmission is necessary for parasite invasion, most new infections post-establishment arise from vertical transmission. Our study predicts that multiple transmission routes, coupled with high parasite virulence, can reduce resident host abundance by up to 50%, suggesting that the protozoan could contribute to declines of North American monarchs.
Collapse
Affiliation(s)
- Ania A Majewska
- Odum School of Ecology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.,Center for the Ecology of Infectious Disease, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.,Department of Biology, Emory University, Atlanta, GA, USA
| | - Stuart Sims
- Odum School of Ecology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Anna Schneider
- Wisconsin Department of Natural Resources, Madison, WI, USA
| | - Sonia Altizer
- Odum School of Ecology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.,Center for the Ecology of Infectious Disease, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Richard J Hall
- Odum School of Ecology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.,Center for the Ecology of Infectious Disease, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.,Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| |
Collapse
|
29
|
Li X, Xu B, Shaman J. The Impact of Environmental Transmission and Epidemiological Features on the Geographical Translocation of Highly Pathogenic Avian Influenza Virus. Int J Environ Res Public Health 2019; 16:ijerph16111890. [PMID: 31142047 PMCID: PMC6603588 DOI: 10.3390/ijerph16111890] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/21/2019] [Accepted: 05/22/2019] [Indexed: 11/16/2022]
Abstract
The factors affecting the transmission and geographic translocation of avian influenza viruses (AIVs) within wild migratory bird populations remain inadequately understood. In a previous study, we found that environmental transmission had little impact on AIV translocation in a model of a single migratory bird population. In order to simulate virus transmission and translocation more realistically, here we expanded this model system to include two migratory bird flocks. We simulated AIV transmission and translocation while varying four core properties: 1) Contact transmission rate; 2) infection recovery rate; 3) infection-induced mortality rate; and 4) migration recovery rate; and three environmental transmission properties: 1) Virion persistence; 2) exposure rate; and 3) re-scaled environmental infectiousness; as well as the time lag in the migration schedule of the two flocks. We found that environmental exposure rate had a significant impact on virus translocation in the two-flock model. Further, certain epidemiological features (i.e., low infection recovery rate, low mortality rate, and high migration transmission rate) in both flocks strongly affected the likelihood of virus translocation. Our results further identified the pathobiological features supporting AIV intercontinental dissemination risk.
Collapse
Affiliation(s)
- Xueying Li
- Ministry of Education Key Laboratory for Earth System Modelling, Department of Earth System Science, Tsinghua, Beijing 100084, China.
| | - Bing Xu
- Ministry of Education Key Laboratory for Earth System Modelling, Department of Earth System Science, Tsinghua, Beijing 100084, China.
- State Key Laboratory of Remote Sensing Science, College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China.
| | - Jeffrey Shaman
- Department of Environmental Health Sciences, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
30
|
Becker DJ, Teitelbaum CS, Murray MH, Curry SE, Welch CN, Ellison T, Adams HC, Rozier RS, Lipp EK, Hernandez SM, Altizer S, Hall RJ. Assessing the contributions of intraspecific and environmental sources of infection in urban wildlife: Salmonella enterica and white ibis as a case study. J R Soc Interface 2018; 15:20180654. [PMID: 30958239 PMCID: PMC6303792 DOI: 10.1098/rsif.2018.0654] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 08/30/2018] [Accepted: 11/15/2018] [Indexed: 01/11/2023] Open
Abstract
Conversion of natural habitats into urban landscapes can expose wildlife to novel pathogens and alter pathogen transmission pathways. Because transmission is difficult to quantify for many wildlife pathogens, mathematical models paired with field observations can help select among competing transmission pathways that might operate in urban landscapes. Here we develop a mathematical model for the enteric bacteria Salmonella enterica in urban-foraging white ibis ( Eudocimus albus) in south Florida as a case study to determine (i) the relative importance of contact-based versus environmental transmission among ibis and (ii) whether transmission can be supported by ibis alone or requires external sources of infection. We use biannual field prevalence data to restrict model outputs generated from a Latin hypercube sample of parameter space and select among competing transmission scenarios. We find the most support for transmission from environmental uptake rather than between-host contact and that ibis-ibis transmission alone could maintain low infection prevalence. Our analysis provides the first parameter estimates for Salmonella shedding and uptake in a wild bird and provides a key starting point for predicting how ibis response to urbanization alters their exposure to a multi-host zoonotic enteric pathogen. More broadly, our study provides an analytical roadmap to assess transmission pathways of multi-host wildlife pathogens in the face of scarce infection data.
Collapse
Affiliation(s)
- Daniel J. Becker
- Odum School of Ecology, University of Georgia, Athens, GA, USA
- Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA, USA
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Claire S. Teitelbaum
- Odum School of Ecology, University of Georgia, Athens, GA, USA
- Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA, USA
| | - Maureen H. Murray
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA
- Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, GA, USA
| | - Shannon E. Curry
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA
- Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, GA, USA
| | - Catharine N. Welch
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA
- Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, GA, USA
| | - Taylor Ellison
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA
- Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, GA, USA
| | - Henry C. Adams
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA
- Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, GA, USA
| | - R. Scott Rozier
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA
| | - Erin K. Lipp
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA
| | - Sonia M. Hernandez
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA
- Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, GA, USA
| | - Sonia Altizer
- Odum School of Ecology, University of Georgia, Athens, GA, USA
- Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA, USA
| | - Richard J. Hall
- Odum School of Ecology, University of Georgia, Athens, GA, USA
- Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA, USA
- Department of Infectious Disease, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| |
Collapse
|
31
|
Fearnley EJ, Lal A, Bates J, Stafford R, Kirk MD, Glass K. Salmonella source attribution in a subtropical state of Australia: capturing environmental reservoirs of infection. Epidemiol Infect 2018; 146:1903-8. [PMID: 30103838 DOI: 10.1017/S0950268818002224] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Salmonellosis is a leading cause of hospitalisation due to gastroenteritis in Australia. A previous source attribution analysis for a temperate state in Australia attributed most infections to chicken meat or eggs. Queensland is in northern Australia and includes subtropical and tropical climate zones. We analysed Queensland notifications for salmonellosis and conducted source attribution to compare reservoir sources with those in southern Australia. In contrast to temperate Australia, most infections were due to non-Typhimurium serotypes, with particularly high incidence in children under 5 years and strong seasonality, peaking in summer. We attributed 65.3% (95% credible interval (CrI) 60.6-73.2) of cases to either chicken meat or eggs and 15.5% (95% CrI 7.0-19.5) to nuts. The subtypes with the strongest associations with nuts were Salmonella Aberdeen, S. Birkenhead, S. Hvittingfoss, S. Potsdam and S. Waycross. All five subtypes had high rates of illness in children under 5 years (ranging from 4/100 000 to 23/100 000), suggesting that nuts may be serving as a proxy for environmental transmission in the model. Australia's climatic range allows us to conduct source attribution in different climate zones with similar food consumption patterns. This attribution provides evidence for environment-mediated transmission of salmonellosis in sub-tropical regions.
Collapse
|
32
|
Carlson CJ, Getz WM, Kausrud KL, Cizauskas CA, Blackburn JK, Bustos Carrillo FA, Colwell R, Easterday WR, Ganz HH, Kamath PL, Økstad OA, Turner WC, Kolstø AB, Stenseth NC. Spores and soil from six sides: interdisciplinarity and the environmental biology of anthrax (Bacillus anthracis). Biol Rev Camb Philos Soc 2018; 93:1813-1831. [PMID: 29732670 DOI: 10.1111/brv.12420] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 12/11/2022]
Abstract
Environmentally transmitted diseases are comparatively poorly understood and managed, and their ecology is particularly understudied. Here we identify challenges of studying environmental transmission and persistence with a six-sided interdisciplinary review of the biology of anthrax (Bacillus anthracis). Anthrax is a zoonotic disease capable of maintaining infectious spore banks in soil for decades (or even potentially centuries), and the mechanisms of its environmental persistence have been the topic of significant research and controversy. Where anthrax is endemic, it plays an important ecological role, shaping the dynamics of entire herbivore communities. The complex eco-epidemiology of anthrax, and the mysterious biology of Bacillus anthracis during its environmental stage, have necessitated an interdisciplinary approach to pathogen research. Here, we illustrate different disciplinary perspectives through key advances made by researchers working in Etosha National Park, a long-term ecological research site in Namibia that has exemplified the complexities of the enzootic process of anthrax over decades of surveillance. In Etosha, the role of scavengers and alternative routes (waterborne transmission and flies) has proved unimportant relative to the long-term persistence of anthrax spores in soil and their infection of herbivore hosts. Carcass deposition facilitates green-ups of vegetation to attract herbivores, potentially facilitated by the role of anthrax spores in the rhizosphere. The underlying seasonal pattern of vegetation, and herbivores' immune and behavioural responses to anthrax risk, interact to produce regular 'anthrax seasons' that appear to be a stable feature of the Etosha ecosystem. Through the lens of microbiologists, geneticists, immunologists, ecologists, epidemiologists, and clinicians, we discuss how anthrax dynamics are shaped at the smallest scale by population genetics and interactions within the bacterial communities up to the broadest scales of ecosystem structure. We illustrate the benefits and challenges of this interdisciplinary approach to disease ecology, and suggest ways anthrax might offer insights into the biology of other important pathogens. Bacillus anthracis, and the more recently emerged Bacillus cereus biovar anthracis, share key features with other environmentally transmitted pathogens, including several zoonoses and panzootics of special interest for global health and conservation efforts. Understanding the dynamics of anthrax, and developing interdisciplinary research programs that explore environmental persistence, is a critical step forward for understanding these emerging threats.
Collapse
Affiliation(s)
- Colin J Carlson
- National Socio-Environmental Synthesis Center (SESYNC), University of Maryland, Annapolis, MD 21401, U.S.A.,Department of Biology, Georgetown University, Washington, DC 20057, U.S.A
| | - Wayne M Getz
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, U.S.A.,School of Mathematical Sciences, University of KwaZulu-Natal, PB X 54001, Durban 4000, South Africa
| | - Kyrre L Kausrud
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, N-0316, Oslo, Norway
| | - Carrie A Cizauskas
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, U.S.A
| | - Jason K Blackburn
- Spatial Epidemiology & Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, U.S.A.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, U.S.A
| | - Fausto A Bustos Carrillo
- Department of Epidemiology & Department of Biostatistics, School of Public Health, University of California, Berkeley, CA 94720-7360, U.S.A
| | - Rita Colwell
- CosmosID Inc., Rockville, MD 20850, U.S.A.,Center for Bioinformatics and Computational Biology, University of Maryland Institute for Advanced Computer Studies, University of Maryland, College Park, MD 20742, U.S.A.,Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, U.S.A
| | - W Ryan Easterday
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, N-0316, Oslo, Norway
| | - Holly H Ganz
- UC Davis Genome Center, University of California, Davis, CA 95616, U.S.A
| | - Pauline L Kamath
- School of Food and Agriculture, University of Maine, Orono, ME 04469, U.S.A
| | - Ole A Økstad
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, N-0316, Oslo, Norway
| | - Wendy C Turner
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, U.S.A
| | - Anne-Brit Kolstø
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, N-0316, Oslo, Norway
| | - Nils C Stenseth
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, N-0316, Oslo, Norway
| |
Collapse
|
33
|
Harada H, Fujimori Y, Gomi R, Ahsan MN, Fujii S, Sakai A, Matsuda T. Pathotyping of Escherichia coli isolated from community toilet wastewater and stored drinking water in a slum in Bangladesh. Lett Appl Microbiol 2018; 66:542-548. [PMID: 29574855 DOI: 10.1111/lam.12878] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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: 01/18/2018] [Revised: 02/19/2018] [Accepted: 03/09/2018] [Indexed: 12/21/2022]
Abstract
This study investigated the occurrence of Escherichia coli pathotypes in sanitary wastewater and drinking water in a Bangladeshi urban slum and the potential associations between these sources. We examined 621 E. coli isolates from sanitary wastewater and stored drinking water by multiplex PCR and dual-index sequencing, classifying them into eight pathotypes based on 14 virulence genes and additionally evaluating the possession of the human-specific E. coli genetic biomarker H8. The proportions of pathogenic E. coli were significantly different (P < 0·001) between wastewater (18·6%) and drinking water (1·7%). StIb-positive enterotoxigenic E. coli (ETEC) were predominant in wastewater, indicating that people in the site carried ETEC. In contrast, no ETEC was present in drinking water and the proportion of H8-positive isolates was significantly smaller (7·8%) than that in wastewater (16·3%) (P = 0·001). Our findings indicate that sanitary wastewater from the slum was heavily contaminated with pathogenic E. coli, posing a great health risk. Furthermore, E. coli contamination of drinking water could be derived from not only human but also other sources. SIGNIFICANCE AND IMPACT OF THE STUDY Sanitary wastewater from an urban slum was heavily contaminated with pathogenic Escherichia coli. It is worth noting a great health risk of accidental exposure to pathogenically contaminated wastewater improperly discharged in and around urban slums. The distinct difference in pathotypes between wastewater and drinking water and the significantly smaller positive proportion of the human-specific E. coli genetic biomarker (H8) in drinking water indicate that drinking water contamination could be derived from not only human but also other sources. This highlights that pathotyping in association with the H8 marker provides an indication of pathogen contamination sources of environmental transmission media.
Collapse
Affiliation(s)
- H Harada
- Graduate School of Global Environmental Studies, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Y Fujimori
- Graduate School of Global Environmental Studies, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - R Gomi
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, Japan
| | - Md N Ahsan
- Life Science School, Khulna University, Khulna, Bangladesh
| | - S Fujii
- Graduate School of Global Environmental Studies, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - A Sakai
- University of Marketing and Distribution Sciences, Nishi-ku, Kobe, Japan
| | - T Matsuda
- Research Center for Environmental Quality Management, Kyoto University, Otsu, Shiga, Japan
| |
Collapse
|
34
|
Dallas TA, Krkošek M, Drake JM. Experimental evidence of a pathogen invasion threshold. R Soc Open Sci 2018; 5:171975. [PMID: 29410876 PMCID: PMC5792953 DOI: 10.1098/rsos.171975] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 12/11/2017] [Indexed: 05/15/2023]
Abstract
Host density thresholds to pathogen invasion separate regions of parameter space corresponding to endemic and disease-free states. The host density threshold is a central concept in theoretical epidemiology and a common target of human and wildlife disease control programmes, but there is mixed evidence supporting the existence of thresholds, especially in wildlife populations or for pathogens with complex transmission modes (e.g. environmental transmission). Here, we demonstrate the existence of a host density threshold for an environmentally transmitted pathogen by combining an epidemiological model with a microcosm experiment. Experimental epidemics consisted of replicate populations of naive crustacean zooplankton (Daphnia dentifera) hosts across a range of host densities (20-640 hosts l-1) that were exposed to an environmentally transmitted fungal pathogen (Metschnikowia bicuspidata). Epidemiological model simulations, parametrized independently of the experiment, qualitatively predicted experimental pathogen invasion thresholds. Variability in parameter estimates did not strongly influence outcomes, though systematic changes to key parameters have the potential to shift pathogen invasion thresholds. In summary, we provide one of the first clear experimental demonstrations of pathogen invasion thresholds in a replicated experimental system, and provide evidence that such thresholds may be predictable using independently constructed epidemiological models.
Collapse
Affiliation(s)
- Tad A. Dallas
- Department of Environmental Science and Policy, University of California, Davis, CA, USA
- Odum School of Ecology, University of Georgia, Athens, GA, USA
| | - Martin Krkošek
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - John M. Drake
- Odum School of Ecology, University of Georgia, Athens, GA, USA
- Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA, USA
| |
Collapse
|
35
|
Abstract
We deal with the following question: Can the consumption of contaminated bush meat, the funeral practices and the environmental contamination explain the recurrence and persistence of Ebola virus disease outbreaks in Africa? We develop an SIR-type model which, incorporates both the direct and indirect transmissions in such a manner that there is a provision of Ebola viruses. We prove that the full model has one (endemic) equilibrium which is locally asymptotically stable whereas, it is globally asymptotically stable in the absence of the Ebola virus shedding in the environment. For the sub-model without the provision of Ebola viruses, the disease dies out or stabilizes globally at an endemic equilibrium. At the endemic level, the number of infectious is larger for the full model than for the sub-model without provision of Ebola viruses. We design a nonstandard finite difference scheme, which preserves the dynamics of the model. Numerical simulations are provided.
Collapse
Affiliation(s)
- T Berge
- a Department of Mathematics and Applied Mathematics , University of Pretoria , Pretoria , South Africa
- b Department of Mathematics and Computer Sciences , University of Dschang , Dschang , Cameroon
| | - J M-S Lubuma
- a Department of Mathematics and Applied Mathematics , University of Pretoria , Pretoria , South Africa
| | - G M Moremedi
- c Department of Mathematical Sciences , University of South Africa , Pretoria , South Africa
| | - N Morris
- d Department of Forensic Medicine , University of Pretoria , Pretoria , South Africa
| | - R Kondera-Shava
- e Department of Mathematical Sciences , University of Botswana , Gaborone , Botswana
| |
Collapse
|
36
|
Escobar LE, Carver S, Romero-Alvarez D, VandeWoude S, Crooks KR, Lappin MR, Craft ME. Inferring the Ecological Niche of Toxoplasma gondii and Bartonella spp. in Wild Felids. Front Vet Sci 2017; 4:172. [PMID: 29090215 PMCID: PMC5650989 DOI: 10.3389/fvets.2017.00172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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: 03/31/2017] [Accepted: 09/28/2017] [Indexed: 11/13/2022] Open
Abstract
Traditional epidemiological studies of disease in animal populations often focus on directly transmitted pathogens. One reason pathogens with complex lifecycles are understudied could be due to challenges associated with detection in vectors and the environment. Ecological niche modeling (ENM) is a methodological approach that overcomes some of the detection challenges often seen with vector or environmentally dependent pathogens. We test this approach using a unique dataset of two pathogens in wild felids across North America: Toxoplasma gondii and Bartonella spp. in bobcats (Lynx rufus) and puma (Puma concolor). We found three main patterns. First, T. gondii showed a broader use of environmental conditions than did Bartonella spp. Also, ecological niche models, and Normalized Difference Vegetation Index satellite imagery, were useful even when applied to wide-ranging hosts. Finally, ENM results from one region could be applied to other regions, thus transferring information across different landscapes. With this research, we detail the uncertainty of epidemiological risk models across novel environments, thereby advancing tools available for epidemiological decision-making. We propose that ENM could be a valuable tool for enabling understanding of transmission risk, contributing to more focused prevention and control options for infectious diseases.
Collapse
Affiliation(s)
- Luis E Escobar
- Department of Veterinary Population Medicine, University of Minnesota, Minneapolis, MN, United States.,Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota, St. Paul, MN, United States.,Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, United States
| | - Scott Carver
- School of Biological Sciences, University of Tasmania, Hobart, TAS, Australia
| | - Daniel Romero-Alvarez
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, United States
| | - Sue VandeWoude
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Kevin R Crooks
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO, United States
| | - Michael R Lappin
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO, United States
| | - Meggan E Craft
- Department of Veterinary Population Medicine, University of Minnesota, Minneapolis, MN, United States
| |
Collapse
|
37
|
Abstract
In this paper, a multi-strain model that links immunological and epidemiological dynamics across scales is formulated. On the within-host scale, the n strains eliminate each other with the strain having the largest immunological reproduction number persisting. However, on the population scale, we extend the competitive exclusion principle to a multi-strain model of SI-type for the dynamics of highly pathogenic flu in poultry that incorporates both the infection age of infectious individuals and biological age of pathogen in the environment. The two models are linked through the age-since-infection structure of the epidemiological variables. In addition the between-host transmission rate, the shedding rate of individuals infected by strain j and the disease-induced death rate depend on the within-host viral load. The immunological reproduction numbers [Formula: see text] and the epidemiological reproduction numbers [Formula: see text] are computed. By constructing a suitable Lyapunov function, the global stability of the infection-free equilibrium in the system is obtained if all reproduction numbers are smaller or equal to one. If [Formula: see text], the reproduction number of strain j is larger than one, then a single-strain equilibrium, corresponding to strain j exists. This single-strain equilibrium is globally stable whenever [Formula: see text] and [Formula: see text] is the unique maximal reproduction number and all of the reproduction numbers are distinct. That is, the strain with the maximal basic reproduction number competitively excludes all other strains.
Collapse
Affiliation(s)
- Yan-Xia Dang
- a Department of Public Education , Zhumadian Vocational and Technical College , Zhumadian , People's Republic of China
| | - Xue-Zhi Li
- b Department of Mathematics and Physics , Anyang Institute of Technology , Anyang , People's Republic of China
| | - Maia Martcheva
- c Department of Mathematics , University of Florida , Gainesville , FL , USA
| |
Collapse
|
38
|
Abstract
Epidemiological models of infectious diseases are essential tools in support of risk assessment, surveillance design, and contingency planning in public and animal health. Direct pathogen transmission from host to host is an essential process of each host–pathogen system and respective epidemiological modeling concepts. It is widely accepted that numerous diseases involve indirect transmission (IT) through pathogens shed by infectious hosts to their environment. However, epidemiological models largely do not represent pathogen persistence outside the host explicitly. We hypothesize that this simplification might bias management-related model predictions for disease agents that can persist outside their host for a certain time span. We adapted an individual-based, spatially explicit epidemiological model that can mimic both transmission processes. One version explicitly simulated indirect pathogen transmission through a contaminated environment. The second version simulated direct host-to-host transmission only. We aligned the model variants by the transmission potential per infectious host (i.e., basic reproductive number R0) and the spatial transmission kernel of the infection to allow unbiased comparison of predictions. The quantitative model results are provided for the example of surveillance plans for early detection of foot-and-mouth disease in wild boar, a social host. We applied systematic sampling strategies on the serological status of randomly selected host individuals in both models. We compared between the model variants the time to detection and the area affected prior to detection, measures that strongly influence mitigation costs. Moreover, the ideal sampling strategy to detect the infection in a given time frame was compared between both models. We found the simplified, direct transmission model to underestimate necessary sample size by up to one order of magnitude but to overestimate the area put under control measures. Thus, the model predictions underestimated surveillance efforts but overestimated mitigation costs. We discuss parameterization of IT models and related knowledge gaps. We conclude that the explicit incorporation of IT mechanisms in epidemiological modeling may reward by adapting surveillance and mitigation efforts.
Collapse
Affiliation(s)
- Martin Lange
- Department of Ecological Modelling, Helmholtz Centre for Environmental Research Leipzig - UFZ , Leipzig , Germany
| | | | - Hans-Hermann Thulke
- Department of Ecological Modelling, Helmholtz Centre for Environmental Research Leipzig - UFZ , Leipzig , Germany
| |
Collapse
|
39
|
Rhea S, Moorman A, Pace R, Mobley V, MacFarquhar J, Robinson E, Hayden T, Thai H, Drobeniuc J, Brooks JT, Moore Z, Patel PR. Hepatitis B Reverse Seroconversion and Transmission in a Hemodialysis Center: A Public Health Investigation and Case Report. Am J Kidney Dis 2016; 68:292-295. [PMID: 27161589 DOI: 10.1053/j.ajkd.2016.03.424] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [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: 11/05/2015] [Accepted: 03/29/2016] [Indexed: 11/11/2022]
Abstract
In March 2013, public health authorities were notified of a new hepatitis B virus (HBV) infection in a patient receiving hemodialysis. We investigated to identify the source and prevent additional infections. We reviewed medical records, interviewed the index patient regarding hepatitis B risk factors, performed HBV molecular analysis, and observed infection control practices at the outpatient hemodialysis facility where she received care. The index patient's only identified hepatitis B risk factor was hemodialysis treatment. The facility had no other patients with known active HBV infection. One patient had evidence of a resolved HBV infection. Investigation of this individual, who was identified as the source patient, indicated that HBV reverse seroconversion and reactivation had occurred in the setting of HIV (human immunodeficiency virus) infection and a failed kidney transplant. HBV whole genome sequences analysis from the index and source patients indicated 99.9% genetic homology. Facility observations revealed multiple infection control breaches. Inadequate dilution of the source patient's sample during HBV testing might have led to a false-negative result, delaying initiation of hemodialysis in isolation. In conclusion, HBV transmission occurred after an HIV-positive hemodialysis patient with transplant-related immunosuppression experienced HBV reverse seroconversion and reactivation. Providers should be aware of this possibility, especially among severely immunosuppressed patients, and maintain stringent infection control.
Collapse
Affiliation(s)
- Sarah Rhea
- Epidemic Intelligence Service, CDC, Atlanta, GA; North Carolina Department of Health and Human Services, Raleigh, NC.
| | | | - Robert Pace
- North Carolina Department of Health and Human Services, Raleigh, NC
| | - Victoria Mobley
- North Carolina Department of Health and Human Services, Raleigh, NC
| | - Jennifer MacFarquhar
- North Carolina Department of Health and Human Services, Raleigh, NC; Office of Public Health Preparedness and Response, CDC, Atlanta, GA
| | | | | | - Hong Thai
- Division of Viral Hepatitis, CDC, Atlanta, GA
| | | | - John T Brooks
- Division of HIV/AIDS Prevention Surveillance and Epidemiology, CDC, Atlanta, GA
| | - Zack Moore
- North Carolina Department of Health and Human Services, Raleigh, NC
| | - Priti R Patel
- Division of Healthcare Quality Promotion, CDC, Atlanta, GA
| |
Collapse
|
40
|
Leach CB, Webb CT, Cross PC. When environmentally persistent pathogens transform good habitat into ecological traps. R Soc Open Sci 2016; 3:160051. [PMID: 27069672 PMCID: PMC4821283 DOI: 10.1098/rsos.160051] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 02/19/2016] [Indexed: 06/05/2023]
Abstract
Habitat quality plays an important role in the dynamics and stability of wildlife metapopulations. However, the benefits of high-quality habitat may be modulated by the presence of an environmentally persistent pathogen. In some cases, the presence of environmental pathogen reservoirs on high-quality habitat may lead to the creation of ecological traps, wherein host individuals preferentially colonize high-quality habitat, but are then exposed to increased infection risk and disease-induced mortality. We explored this possibility through the development of a stochastic patch occupancy model, where we varied the pathogen's virulence, transmission rate and environmental persistence as well as the distribution of habitat quality in the host metapopulation. This model suggests that for pathogens with intermediate levels of spread, high-quality habitat can serve as an ecological trap, and can be detrimental to host persistence relative to low-quality habitat. This inversion of the relative roles of high- and low-quality habitat highlights the importance of considering the interaction between spatial structure and pathogen transmission when managing wildlife populations exposed to an environmentally persistent pathogen.
Collapse
Affiliation(s)
- Clinton B. Leach
- Department of Biology, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, USA
| | - Colleen T. Webb
- Department of Biology, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, USA
| | - Paul C. Cross
- US Geological Survey, Northern Rocky Mountain Science Center, Bozeman, MT, USA
| |
Collapse
|
41
|
Soto W, Nishiguchi MK. Microbial experimental evolution as a novel research approach in the Vibrionaceae and squid-Vibrio symbiosis. Front Microbiol 2014; 5:593. [PMID: 25538686 PMCID: PMC4260504 DOI: 10.3389/fmicb.2014.00593] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [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] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 10/20/2014] [Indexed: 12/21/2022] Open
Abstract
The Vibrionaceae are a genetically and metabolically diverse family living in aquatic habitats with a great propensity toward developing interactions with eukaryotic microbial and multicellular hosts (as either commensals, pathogens, and mutualists). The Vibrionaceae frequently possess a life history cycle where bacteria are attached to a host in one phase and then another where they are free from their host as either part of the bacterioplankton or adhered to solid substrates such as marine sediment, riverbeds, lakebeds, or floating particulate debris. These two stages in their life history exert quite distinct and separate selection pressures. When bound to solid substrates or to host cells, the Vibrionaceae can also exist as complex biofilms. The association between bioluminescent Vibrio spp. and sepiolid squids (Cephalopoda: Sepiolidae) is an experimentally tractable model to study bacteria and animal host interactions, since the symbionts and squid hosts can be maintained in the laboratory independently of one another. The bacteria can be grown in pure culture and the squid hosts raised gnotobiotically with sterile light organs. The partnership between free-living Vibrio symbionts and axenic squid hatchlings emerging from eggs must be renewed every generation of the cephalopod host. Thus, symbiotic bacteria and animal host can each be studied alone and together in union. Despite virtues provided by the Vibrionaceae and sepiolid squid-Vibrio symbiosis, these assets to evolutionary biology have yet to be fully utilized for microbial experimental evolution. Experimental evolution studies already completed are reviewed, along with exploratory topics for future study.
Collapse
Affiliation(s)
- William Soto
- BEACON Center for the Study of Evolution in Action, Michigan State UniversityEast Lansing, MI, USA
| | | |
Collapse
|
42
|
Abstract
BACKGROUND Using three independent methods, prior studies in Swedish sibling pairs indicate that environmental factors contribute substantially to familial aggregation for drug abuse (DA). Could we replicate these results in cousin pairs? METHOD Using multiple Swedish public databases (1964-2011), we defined DA using medical, legal or pharmacy registry records and examined concordance in full cousin pairs as a function of age differences, younger-older relationships and geographical proximity while growing up. RESULTS Replicating prior results in siblings, cousin pairs were significantly more similar in their history of DA if they were (i) closer versus more distant in age and (ii) grew up in high versus low geographical proximity to one another. Furthermore, controlling for background factors, having an older cousin with DA conveys a greater risk for DA than having a younger drug-abusing cousin. The greater transmission of DA from older to younger versus younger to older cousin was more prominent in pairs who grew up close to one another. In age difference and geographical proximity analyses, effects were consistently strongest in male-male cousin pairs. In analyses of older → younger versus younger → older transmission, effects were stronger in male-male and male-female than in female-female or female-male relative pairs. CONCLUSIONS In accord with prior results in siblings, environmental factors contribute substantially to the familial aggregation of DA in cousins and these effects are, in general, stronger in males than in females.
Collapse
Affiliation(s)
- K. S. Kendler
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, USA
- Department of Psychiatry, Virginia Commonwealth University, Richmond VA, USA
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA, USA
| | - H. Ohlsson
- Center for Primary Health Care Research, Lund University, Malmö, Sweden
| | - K. Sundquist
- Center for Primary Health Care Research, Lund University, Malmö, Sweden
- Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, CA, USA
| | - J. Sundquist
- Center for Primary Health Care Research, Lund University, Malmö, Sweden
- Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, CA, USA
| |
Collapse
|
43
|
Fuller E, Elderd BD, Dwyer G. Pathogen persistence in the environment and insect-baculovirus interactions: disease-density thresholds, epidemic burnout, and insect outbreaks. Am Nat 2012; 179:E70-96. [PMID: 22322229 PMCID: PMC3814039 DOI: 10.1086/664488] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [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] [Indexed: 11/03/2022]
Abstract
Classical epidemic theory focuses on directly transmitted pathogens, but many pathogens are instead transmitted when hosts encounter infectious particles. Theory has shown that for such diseases pathogen persistence time in the environment can strongly affect disease dynamics, but estimates of persistence time, and consequently tests of the theory, are extremely rare. We consider the consequences of persistence time for the dynamics of the gypsy moth baculovirus, a pathogen transmitted when larvae consume foliage contaminated with particles released from infectious cadavers. Using field-transmission experiments, we are able to estimate persistence time under natural conditions, and inserting our estimates into a standard epidemic model suggests that epidemics are often terminated by a combination of pupation and burnout rather than by burnout alone, as predicted by theory. Extending our models to allow for multiple generations, and including environmental transmission over the winter, suggests that the virus may survive over the long term even in the absence of complex persistence mechanisms, such as environmental reservoirs or covert infections. Our work suggests that estimates of persistence times can lead to a deeper understanding of environmentally transmitted pathogens and illustrates the usefulness of experiments that are closely tied to mathematical models.
Collapse
Affiliation(s)
- Emma Fuller
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois 60637, USA
| | | | | |
Collapse
|