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Carlson CJ, Garnier R, Tiu A, Luby SP, Bansal S. Strategic vaccine stockpiles for regional epidemics of emerging viruses: A geospatial modeling framework. Vaccine 2024; 42:126051. [PMID: 38902187 DOI: 10.1016/j.vaccine.2024.06.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 06/22/2024]
Abstract
Multinational epidemics of emerging infectious diseases are increasingly common, due to anthropogenic pressure on ecosystems and the growing connectivity of human populations. Early and efficient vaccination can contain outbreaks and prevent mass mortality, but optimal vaccine stockpiling strategies are dependent on pathogen characteristics, reservoir ecology, and epidemic dynamics. Here, we model major regional outbreaks of Nipah virus and Middle East respiratory syndrome, and use these to develop a generalized framework for estimating vaccine stockpile needs based on spillover geography, spatially-heterogeneous healthcare capacity and spatially-distributed human mobility networks. Because outbreak sizes were highly skewed, we found that most outbreaks were readily contained (median stockpile estimate for MERS-CoV: 2,089 doses; Nipah: 1,882 doses), but the maximum estimated stockpile need in a highly unlikely large outbreak scenario was 2-3 orders of magnitude higher (MERS-CoV: ∼87,000 doses; Nipah ∼ 1.1 million doses). Sensitivity analysis revealed that stockpile needs were more dependent on basic epidemiological parameters (i.e., death and recovery rate) and healthcare availability than any uncertainty related to vaccine efficacy or deployment strategy. Our results highlight the value of descriptive epidemiology for real-world modeling applications, and suggest that stockpile allocation should consider ecological, epidemiological, and social dimensions of risk.
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Affiliation(s)
- Colin J Carlson
- Department of Biology, Georgetown University; Department of Epidemiology of Microbial Diseases, Yale University School of Public Health
| | | | - Andrew Tiu
- Department of Biology, Georgetown University
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2
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Sessions Z, Bobrowski T, Martin HJ, Beasley JMT, Kothari A, Phares T, Li M, Alves VM, Scotti MT, Moorman NJ, Baric R, Tropsha A, Muratov EN. Praemonitus praemunitus: can we forecast and prepare for future viral disease outbreaks? FEMS Microbiol Rev 2023; 47:fuad048. [PMID: 37596064 PMCID: PMC10532129 DOI: 10.1093/femsre/fuad048] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 07/04/2023] [Accepted: 08/17/2023] [Indexed: 08/20/2023] Open
Abstract
Understanding the origins of past and present viral epidemics is critical in preparing for future outbreaks. Many viruses, including SARS-CoV-2, have led to significant consequences not only due to their virulence, but also because we were unprepared for their emergence. We need to learn from large amounts of data accumulated from well-studied, past pandemics and employ modern informatics and therapeutic development technologies to forecast future pandemics and help minimize their potential impacts. While acknowledging the complexity and difficulties associated with establishing reliable outbreak predictions, herein we provide a perspective on the regions of the world that are most likely to be impacted by future outbreaks. We specifically focus on viruses with epidemic potential, namely SARS-CoV-2, MERS-CoV, DENV, ZIKV, MAYV, LASV, noroviruses, influenza, Nipah virus, hantaviruses, Oropouche virus, MARV, and Ebola virus, which all require attention from both the public and scientific community to avoid societal catastrophes like COVID-19. Based on our literature review, data analysis, and outbreak simulations, we posit that these future viral epidemics are unavoidable, but that their societal impacts can be minimized by strategic investment into basic virology research, epidemiological studies of neglected viral diseases, and antiviral drug discovery.
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Affiliation(s)
- Zoe Sessions
- Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, 301 Pharmacy Ln, Chapel Hill, NC 27599, United States
| | - Tesia Bobrowski
- Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, 301 Pharmacy Ln, Chapel Hill, NC 27599, United States
| | - Holli-Joi Martin
- Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, 301 Pharmacy Ln, Chapel Hill, NC 27599, United States
| | - Jon-Michael T Beasley
- Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, 301 Pharmacy Ln, Chapel Hill, NC 27599, United States
| | - Aneri Kothari
- Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, 301 Pharmacy Ln, Chapel Hill, NC 27599, United States
| | - Trevor Phares
- Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, 301 Pharmacy Ln, Chapel Hill, NC 27599, United States
- School of Chemistry, University of Louisville, 2320 S Brook St, Louisville, KY 40208, United States
| | - Michael Li
- Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, 301 Pharmacy Ln, Chapel Hill, NC 27599, United States
| | - Vinicius M Alves
- Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, 301 Pharmacy Ln, Chapel Hill, NC 27599, United States
| | - Marcus T Scotti
- Department of Pharmaceutical Sciences, Federal University of Paraiba, Campus I Lot. Cidade Universitaria, PB, 58051-900, Brazil
| | - Nathaniel J Moorman
- Department of Microbiology and Immunology, University of North Carolina, 116 Manning Drive, Chapel Hill, NC 27599, United States
| | - Ralph Baric
- Department of Epidemiology, University of North Carolina, 401 Pittsboro St, Chapel Hill, NC 27599, United States
| | - Alexander Tropsha
- Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, 301 Pharmacy Ln, Chapel Hill, NC 27599, United States
| | - Eugene N Muratov
- Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, 301 Pharmacy Ln, Chapel Hill, NC 27599, United States
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Chaiyes A, Duengkae P, Suksavate W, Pongpattananurak N, Wacharapluesadee S, Olival KJ, Srikulnath K, Pattanakiat S, Hemachudha T. Mapping Risk of Nipah Virus Transmission from Bats to Humans in Thailand. ECOHEALTH 2022; 19:175-189. [PMID: 35657574 PMCID: PMC10116436 DOI: 10.1007/s10393-022-01588-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
Nipah virus (NiV) is a zoonotic virus that can pose a serious threat to human and livestock health. Old-world fruit bats (Pteropus spp.) are the natural reservoir hosts for NiV, and Pteropus lylei, Lyle's flying fox, is an important host of NiV in mainland Southeast Asia. NiV can be transmitted from bats to humans directly via bat-contaminated foods (i.e., date palm sap or fruit) or indirectly via livestock or other intermediate animal hosts. Here we construct risk maps for NiV spillover and transmission by combining ecological niche models for the P. lylei bat reservoir with other spatial data related to direct or indirect NiV transmission (livestock density, foodborne sources including fruit production, and human population). We predict the current and future (2050 and 2070) distribution of P. lylei across Thailand, Cambodia, and Vietnam. Our best-fit model predicted that central and western regions of Thailand and small areas in Cambodia are currently the most suitable habitats for P. lylei. However, due to climate change, the species range is predicted to expand to include lower northern, northeastern, eastern, and upper southern Thailand and almost all of Cambodia and lower southern Vietnam. This expansion will create additional risk areas for human infection from P. lylei in Thailand. Our combined predictive risk maps showed that central Thailand, inhabited by 2.3 million people, is considered highly suitable for the zoonotic transmission of NiV from P. lylei. These current and future NiV transmission risk maps can be used to prioritize sites for active virus surveillance and developing awareness and prevention programs to reduce the risk of NiV spillover and spread in Thailand.
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Affiliation(s)
- Aingorn Chaiyes
- School of Agricultural and Cooperatives, Sukhothai Thammathirat Open University, Nonthaburi, 11120, Thailand
| | - Prateep Duengkae
- Special Research Unit for Wildlife Genomics, Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok, 10900, Thailand.
- Center for Advanced Studies in Tropical Natural Resources, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand.
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand.
| | - Warong Suksavate
- Special Research Unit for Wildlife Genomics, Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok, 10900, Thailand
- Center for Advanced Studies in Tropical Natural Resources, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand
| | - Nantachai Pongpattananurak
- Special Research Unit for Wildlife Genomics, Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok, 10900, Thailand
- Center for Advanced Studies in Tropical Natural Resources, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand
| | - Supaporn Wacharapluesadee
- King Chulalongkorn Memorial Hospital Faculty of Medicine, Thai Red Cross Emerging Infectious Diseases - Health Science Centre, World Health Organization Collaborating Centre for Research and Training on Viral Zoonoses, Chulalongkorn University, Patumwan, Bangkok, 10330, Thailand
| | | | - Kornsorn Srikulnath
- Special Research Unit for Wildlife Genomics, Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok, 10900, Thailand
- Center for Advanced Studies in Tropical Natural Resources, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand
| | - Sura Pattanakiat
- Faculty of Environment and Resource Studies, Mahidol University, Nakhon Pathom, 73170, Thailand
| | - Thiravat Hemachudha
- King Chulalongkorn Memorial Hospital Faculty of Medicine, Thai Red Cross Emerging Infectious Diseases - Health Science Centre, World Health Organization Collaborating Centre for Research and Training on Viral Zoonoses, Chulalongkorn University, Patumwan, Bangkok, 10330, Thailand
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Winter SN, Kirchgessner MS, Frimpong EA, Escobar LE. A Landscape Epidemiological Approach for Predicting Chronic Wasting Disease: A Case Study in Virginia, US. Front Vet Sci 2021; 8:698767. [PMID: 34504887 PMCID: PMC8421794 DOI: 10.3389/fvets.2021.698767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 07/19/2021] [Indexed: 11/23/2022] Open
Abstract
Many infectious diseases in wildlife occur under quantifiable landscape ecological patterns useful in facilitating epidemiological surveillance and management, though little is known about prion diseases. Chronic wasting disease (CWD), a fatal prion disease of the deer family Cervidae, currently affects white-tailed deer (Odocoileus virginianus) populations in the Mid-Atlantic United States (US) and challenges wildlife veterinarians and disease ecologists from its unclear mechanisms and associations within landscapes, particularly in early phases of an outbreak when CWD detections are sparse. We aimed to provide guidance for wildlife disease management by identifying the extent to which CWD-positive cases can be reliably predicted from landscape conditions. Using the CWD outbreak in Virginia, US from 2009 to early 2020 as a case study system, we used diverse algorithms (e.g., principal components analysis, support vector machines, kernel density estimation) and data partitioning methods to quantify remotely sensed landscape conditions associated with CWD cases. We used various model evaluation tools (e.g., AUC ratios, cumulative binomial testing, Jaccard similarity) to assess predictions of disease transmission risk using independent CWD data. We further examined model variation in the context of uncertainty. We provided significant support that vegetation phenology data representing landscape conditions can predict and map CWD transmission risk. Model predictions improved when incorporating inferred home ranges instead of raw hunter-reported coordinates. Different data availability scenarios identified variation among models. By showing that CWD could be predicted and mapped, our project adds to the available tools for understanding the landscape ecology of CWD transmission risk in free-ranging populations and natural conditions. Our modeling framework and use of widely available landscape data foster replicability for other wildlife diseases and study areas.
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Affiliation(s)
- Steven N Winter
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, United States
| | | | - Emmanuel A Frimpong
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, United States
| | - Luis E Escobar
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, United States.,Global Change Center, Virginia Tech, Blacksburg, VA, United States.,Center for Emerging Zoonotic and Arthropod-borne Pathogens, Virginia Tech, Blacksburg, VA, United States
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Jonkmans N, D'Acremont V, Flahault A. Scoping future outbreaks: a scoping review on the outbreak prediction of the WHO Blueprint list of priority diseases. BMJ Glob Health 2021; 6:e006623. [PMID: 34531189 PMCID: PMC8449939 DOI: 10.1136/bmjgh-2021-006623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/01/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The WHO's Research and Development Blueprint priority list designates emerging diseases with the potential to generate public health emergencies for which insufficient preventive solutions exist. The list aims to reduce the time to the availability of resources that can avert public health crises. The current SARS-CoV-2 pandemic illustrates that an effective method of mitigating such crises is the pre-emptive prediction of outbreaks. This scoping review thus aimed to map and identify the evidence available to predict future outbreaks of the Blueprint diseases. METHODS We conducted a scoping review of PubMed, Embase and Web of Science related to the evidence predicting future outbreaks of Ebola and Marburg virus, Zika virus, Lassa fever, Nipah and Henipaviral disease, Rift Valley fever, Crimean-Congo haemorrhagic fever, Severe acute respiratory syndrome, Middle East respiratory syndrome and Disease X. Prediction methods, outbreak features predicted and implementation of predictions were evaluated. We conducted a narrative and quantitative evidence synthesis to highlight prediction methods that could be further investigated for the prevention of Blueprint diseases and COVID-19 outbreaks. RESULTS Out of 3959 articles identified, we included 58 articles based on inclusion criteria. 5 major prediction methods emerged; the most frequent being spatio-temporal risk maps predicting outbreak risk periods and locations through vector and climate data. Stochastic models were predominant. Rift Valley fever was the most predicted disease. Diseases with complex sociocultural factors such as Ebola were often predicted through multifactorial risk-based estimations. 10% of models were implemented by health authorities. No article predicted Disease X outbreaks. CONCLUSIONS Spatiotemporal models for diseases with strong climatic and vectorial components, as in River Valley fever prediction, may currently best reduce the time to the availability of resources. A wide literature gap exists in the prediction of zoonoses with complex sociocultural and ecological dynamics such as Ebola, COVID-19 and especially Disease X.
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Affiliation(s)
- Nils Jonkmans
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Valérie D'Acremont
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Antoine Flahault
- Institute of Global Health, Faculty of Medicine, Université de Genève, Geneva, Switzerland
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6
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Gupta AK, Kumar A, Rajput A, Kaur K, Dar SA, Thakur A, Megha K, Kumar M. NipahVR: a resource of multi-targeted putative therapeutics and epitopes for the Nipah virus. Database (Oxford) 2020; 2020:baz159. [PMID: 32090261 PMCID: PMC7036594 DOI: 10.1093/database/baz159] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/20/2019] [Accepted: 12/23/2020] [Indexed: 12/20/2022]
Abstract
Nipah virus (NiV) is an emerging and priority pathogen from the Paramyxoviridae family with a high fatality rate. It causes various diseases such as respiratory ailments and encephalitis and poses a great threat to humans and livestock. Despite various efforts, there is no approved antiviral treatment available. Therefore, to expedite and assist the research, we have developed an integrative resource NipahVR (http://bioinfo.imtech.res.in/manojk/nipahvr/) for the multi-targeted putative therapeutics and epitopes for NiV. It is structured into different sections, i.e. genomes, codon usage, phylogenomics, molecular diagnostic primers, therapeutics (siRNAs, sgRNAs, miRNAs) and vaccine epitopes (B-cell, CTL, MHC-I and -II binders). Most decisively, potentially efficient therapeutic regimens targeting different NiV proteins and genes were anticipated and projected. We hope this computational resource would be helpful in developing combating strategies against this deadly pathogen. Database URL: http://bioinfo.imtech.res.in/manojk/nipahvr/.
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Affiliation(s)
- Amit Kumar Gupta
- Virology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160036, India
| | - Archit Kumar
- Virology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160036, India
| | - Akanksha Rajput
- Virology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160036, India
| | - Karambir Kaur
- Virology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160036, India
| | - Showkat Ahmed Dar
- Virology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160036, India
| | - Anamika Thakur
- Virology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160036, India
| | - Kirti Megha
- Virology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160036, India
| | - Manoj Kumar
- Virology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160036, India
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Martin G, Yanez-Arenas C, Chen C, Plowright RK, Webb RJ, Skerratt LF. Climate Change Could Increase the Geographic Extent of Hendra Virus Spillover Risk. ECOHEALTH 2018; 15:509-525. [PMID: 29556762 PMCID: PMC6245089 DOI: 10.1007/s10393-018-1322-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 12/10/2017] [Accepted: 01/29/2018] [Indexed: 05/29/2023]
Abstract
Disease risk mapping is important for predicting and mitigating impacts of bat-borne viruses, including Hendra virus (Paramyxoviridae:Henipavirus), that can spillover to domestic animals and thence to humans. We produced two models to estimate areas at potential risk of HeV spillover explained by the climatic suitability for its flying fox reservoir hosts, Pteropus alecto and P. conspicillatus. We included additional climatic variables that might affect spillover risk through other biological processes (such as bat or horse behaviour, plant phenology and bat foraging habitat). Models were fit with a Poisson point process model and a log-Gaussian Cox process. In response to climate change, risk expanded southwards due to an expansion of P. alecto suitable habitat, which increased the number of horses at risk by 175-260% (110,000-165,000). In the northern limits of the current distribution, spillover risk was highly uncertain because of model extrapolation to novel climatic conditions. The extent of areas at risk of spillover from P. conspicillatus was predicted shrink. Due to a likely expansion of P. alecto into these areas, it could replace P. conspicillatus as the main HeV reservoir. We recommend: (1) HeV monitoring in bats, (2) enhancing HeV prevention in horses in areas predicted to be at risk, (3) investigate and develop mitigation strategies for areas that could experience reservoir host replacements.
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Affiliation(s)
- Gerardo Martin
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia.
- , Guadalupe Victoria, Mexico.
- Ecological Health Research Group, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary's campus, Praed Street, London, W2 1NY, UK.
| | - Carlos Yanez-Arenas
- Laboratorio de Conservación de la Biodiversidad, Parque Científico y Tecnológico de Yucatán, Universidad, Universidad Nacional Autónoma de México, Mérida, Yucatán, Mexico
| | - Carla Chen
- Australian Institute of Marine Sciences, Townsville, QLD, Australia
| | - Raina K Plowright
- Bozeman Disease Ecology Lab, Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | - Rebecca J Webb
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Lee F Skerratt
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
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Deka MA, Morshed N. Mapping Disease Transmission Risk of Nipah Virus in South and Southeast Asia. Trop Med Infect Dis 2018; 3:E57. [PMID: 30274453 PMCID: PMC6073609 DOI: 10.3390/tropicalmed3020057] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 05/24/2018] [Accepted: 05/25/2018] [Indexed: 11/16/2022] Open
Abstract
Since 1998, Nipah virus (NiV) (genus: Henipavirus; family: Paramyxoviridae), an often-fatal and highly virulent zoonotic pathogen, has caused sporadic outbreak events. Fruit bats from the genus Pteropus are the wildlife reservoirs and have a broad distribution throughout South and Southeast Asia, and East Africa. Understanding the disease biogeography of NiV is critical to comprehending the potential geographic distribution of this dangerous zoonosis. This study implemented the R packages ENMeval and BIOMOD2 as a means of modeling regional disease transmission risk and additionally measured niche similarity between the reservoir Pteropus and the ecological characteristics of outbreak localities with the Schoener's D index and I statistic. Results indicate a relatively high degree of niche overlap between models in geographic and environmental space (D statistic, 0.64; and I statistic, 0.89), and a potential geographic distribution encompassing 19% (2,963,178 km²) of South and Southeast Asia. This study should contribute to current and future efforts to understand the critical ecological contributors and geography of NiV. Furthermore, this study can be used as a geospatial guide to identify areas of high disease transmission risk and to inform national public health surveillance programs.
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Affiliation(s)
- Mark A Deka
- Department of Geography, Texas State University, 601 University Drive, San Marcos, TX 78666, USA.
| | - Niaz Morshed
- Department of Geography, Texas State University, 601 University Drive, San Marcos, TX 78666, USA.
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9
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Walsh MG, Willem de Smalen A, Mor SM. Wetlands, wild Bovidae species richness and sheep density delineate risk of Rift Valley fever outbreaks in the African continent and Arabian Peninsula. PLoS Negl Trop Dis 2017; 11:e0005756. [PMID: 28742814 PMCID: PMC5526521 DOI: 10.1371/journal.pntd.0005756] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 06/29/2017] [Indexed: 11/24/2022] Open
Abstract
Rift Valley fever (RVF) is an emerging, vector-borne viral zoonosis that has significantly impacted public health, livestock health and production, and food security over the last three decades across large regions of the African continent and the Arabian Peninsula. The potential for expansion of RVF outbreaks within and beyond the range of previous occurrence is unknown. Despite many large national and international epidemics, the landscape epidemiology of RVF remains obscure, particularly with respect to the ecological roles of wildlife reservoirs and surface water features. The current investigation modeled RVF risk throughout Africa and the Arabian Peninsula as a function of a suite of biotic and abiotic landscape features using machine learning methods. Intermittent wetland, wild Bovidae species richness and sheep density were associated with increased landscape suitability to RVF outbreaks. These results suggest the role of wildlife hosts and distinct hydrogeographic landscapes in RVF virus circulation and subsequent outbreaks may be underestimated. These results await validation by studies employing a deeper, field-based interrogation of potential wildlife hosts within high risk taxa. Rift Valley fever (RVF) is a vector-borne zoonotic disease that imparts a substantial burden to the economy and public health of pastoralist communities across the African continent and Arabian Peninsula. Furthermore, RVF is also an emerging pathogen of growing global concern. Knowledge of the epidemiological and ecological factors that influence the geographic distribution of RVF outbreaks and determine risk for humans and animals is incomplete. The current study examined the distribution of RVF outbreaks from 1998 to 2016 and modeled their occurrence as a function of climate, surface water, land cover, livestock density, wild mammalian species richness, and human migration. The results indicate that wetlands, Bovidae species richness, and sheep density were associated with increased risk of RVF outbreaks. Our findings contribute to improved understanding of the spatial and ecological dynamics of RVF risk with a particular emphasis on the distribution of wetlands and potential wildlife reservoirs in designing RVF surveillance programs.
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Affiliation(s)
- Michael G. Walsh
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Westmead, New South Wales, Australia
- Westmead Institute for Medical Research, University of Sydney, Westmead, New South Wales, Australia
- * E-mail:
| | | | - Siobhan M. Mor
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Westmead, New South Wales, Australia
- School of Veterinary Science, Faculty of Science, University of Sydney, Camperdown, New South Wales, Australia
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10
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Martin GA, Yanez-Arenas C, Roberts BJ, Chen C, Plowright RK, Webb RJ, Skerratt LF. Climatic suitability influences species specific abundance patterns of Australian flying foxes and risk of Hendra virus spillover. One Health 2016; 2:115-121. [PMID: 28616484 PMCID: PMC5441320 DOI: 10.1016/j.onehlt.2016.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 07/21/2016] [Accepted: 07/27/2016] [Indexed: 11/30/2022] Open
Abstract
Hendra virus is a paramyxovirus of Australian flying fox bats. It was first detected in August 1994, after the death of 20 horses and one human. Since then it has occurred regularly within a portion of the geographical distribution of all Australian flying fox (fruit bat) species. There is, however, little understanding about which species are most likely responsible for spillover, or why spillover does not occur in other areas occupied by reservoir and spillover hosts. Using ecological niche models of the four flying fox species we were able to identify which species are most likely linked to spillover events using the concept of distance to the niche centroid of each species. With this novel approach we found that 20 out of 27 events occur disproportionately closer to the niche centroid of two species (P. alecto and P. conspicillatus). With linear regressions we found a negative relationship between distance to the niche centroid and abundance of these two species. Thus, we suggest that the bioclimatic niche of these two species is likely driving the spatial pattern of spillover of Hendra virus into horses and ultimately humans.
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Affiliation(s)
- Gerardo A Martin
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Carlos Yanez-Arenas
- Laboratorio de Conservación de la Biodiversidad, Parque Científico y Tecnológico de Yucatán, Universidad Nacional Autónoma de México, Mérida, Yucatán, México
| | - Billie J Roberts
- School of Environment, Griffith University, Brisbane, QLD, Australia
| | - Carla Chen
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Raina K Plowright
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | - Rebecca J Webb
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Lee F Skerratt
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
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Walsh MG. Mapping the risk of Nipah virus spillover into human populations in South and Southeast Asia. Trans R Soc Trop Med Hyg 2015; 109:563-71. [PMID: 26179654 DOI: 10.1093/trstmh/trv055] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 06/24/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Nipah virus (NiV) is a significant emerging zoonotic pathogen given its wide geographic distribution, and the severe morbidity and high mortality that accompanies infection. Moreover, the layered landscape epidemiology surrounding spillover from reservoir host species to humans is ill-defined. Identifying landscape features that contribute to NiV spillover would likely prove helpful in preventing emergence in human populations. METHODS Using an inhomogeneous Poisson model, this study investigated the role of vegetation cover, the human footprint (HFP) and reservoir Pteropus bat distribution to identify the spatial dependence of spillover and map risk across South and Southeast Asia. RESULTS The spatial model identified HFP (RR=1.08; 95% CI 1.05-1.11) and bat distribution (RR=19.44; 95% CI 1.92-196.7) as significant predictors of NiV risk, while vegetation cover was not significant after accounting for HFP and the presence of Pteropus bats. CONCLUSIONS These findings further inform the landscape epidemiology of NiV and suggest specific conduits for spillover in the landscape. However, more detailed field studies will be required to validate these results.
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Affiliation(s)
- Michael G Walsh
- Department of Epidemiology and Biostatistics, School of Public Health, State University of New York, Downstate Medical Center, Brooklyn, New York, USA
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