1
|
Lachmann R, Domingo C, Frank C, Ochs A, Pauly AK, Weber-Schehl M, Schmidt M, Tonn T, Müller TH, Barzon L, Sinigaglia A, Esquevin S, Preußel K, Offergeld R. West Nile Virus Emergence in Germany 2019: Looking for Hidden Human West Nile Virus Infections. Vector Borne Zoonotic Dis 2024; 24:396-401. [PMID: 38573211 DOI: 10.1089/vbz.2023.0103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024] Open
Abstract
Background: Autochthonous human West Nile virus (WNV) infections were notified in the infectious disease surveillance system in Germany in 2018 for the first time and every year since then. Since clinically apparent infections are infrequent, we conducted two studies to investigate subclinical infections of this emerging disease in Germany in 2019 to detect infections not visible to surveillance based on symptomatic infections: limited-scope blood donor testing and a serosurvey among employees at two Berlin zoos with a history of demonstrated WNV infections in animals. Methods: For the zoo study, employees of the two zoos in Berlin were invited to participate in the study in late 2019. Blood samples were drawn and tested for the presence of antibodies (immunoglobulin M [IgM] and immunoglobulin G [IgG]) against WNV, and two other flaviviruses present in Germany: Usutu virus and Tick-borne encephalitis virus (TBEV). For the study in blood donors, four blood establishments with collection sites in regions with documented WNV-infected animals in 2018 and 2019 participated in the study. All donations in these regions were tested for WNV genome from July to November 2019. Results: In the enzyme-linked immunosorbent assay, none of the 70 tested zoo employees were WNV IgM-positive, 8 were WNV IgG-positive, additional 2 participants had equivocal results. All 10 were negative in the virus neutralization test (VNT) for WNV, but positive in the VNT for TBEV. None of the 4273 samples from blood donors tested in areas with WNV-infected animals was positive for WNV-RNA. Conclusion: Our results indicate that WNV circulation in Germany, though clearly documented in animals in 2019, apparently affected very few humans. Still areas with WNV-positive animals remain risk areas for human infection as well.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Michael Schmidt
- Institute of Transfusion Medicine and Immunohematology, German Red Cross Blood Transfusion Service Baden-Württemberg-Hessen, Frankfurt am Main, Germany
| | - Torsten Tonn
- German Red Cross Blood Donation Service North-East, Dresden, Germany
- Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Thomas H Müller
- German Red Cross Blood Service Niedersachsen, Sachsen-Anhalt, Thüringen, Oldenburg, Bremen, Springe, Germany
| | - Luisa Barzon
- Department of Molecular Medicine, University of Padova, Padua, Italy
| | | | | | | | | |
Collapse
|
2
|
McMillan JR, Hamer GL, Levine RS, Mead DG, Waller LA, Goldberg TL, Walker ED, Brawn JD, Ruiz MO, Kitron U, Vazquez-Prokopec G. Multi-Year Comparison of Community- and Species-Level West Nile Virus Antibody Prevalence in Birds from Atlanta, Georgia and Chicago, Illinois, 2005-2016. Am J Trop Med Hyg 2023; 108:366-376. [PMID: 36572005 PMCID: PMC9896344 DOI: 10.4269/ajtmh.21-1086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 09/26/2022] [Indexed: 12/27/2022] Open
Abstract
West Nile virus (WNV) is prevalent in the United States but shows considerable variation in transmission intensity. The purpose of this study was to compare patterns of WNV seroprevalence in avian communities sampled in Atlanta, Georgia and Chicago, Illinois during a 12-year period (Atlanta 2010-2016; Chicago 2005-2012) to reveal regional patterns of zoonotic activity of WNV. WNV antibodies were measured in wild bird sera using ELISA and serum neutralization methods, and seroprevalence among species, year, and location of sampling within each city were compared using binomial-distributed generalized linear mixed-effects models. Seroprevalence was highest in year-round and summer-resident species compared with migrants regardless of region; species explained more variance in seroprevalence within each city. Northern cardinals were the species most likely to test positive for WNV in each city, whereas all other species, on average, tested positive for WNV in proportion to their sample size. Despite similar patterns of seroprevalence among species, overall seroprevalence was higher in Atlanta (13.7%) than in Chicago (5%). Location and year of sampling had minor effects, with location explaining more variation in Atlanta and year explaining more variation in Chicago. Our findings highlight the nature and magnitude of regional differences in WNV urban ecology.
Collapse
Affiliation(s)
- Joseph R. McMillan
- Program in Population Biology, Ecology and Evolution, Emory University, Atlanta, Georgia
| | - Gabriel L. Hamer
- Department of Entomology, Texas A&M University, College Station, Texas
| | - Rebecca S. Levine
- Program in Population Biology, Ecology and Evolution, Emory University, Atlanta, Georgia
| | - Daniel G. Mead
- Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, Georgia
| | - Lance A. Waller
- Program in Population Biology, Ecology and Evolution, Emory University, Atlanta, Georgia;,Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Tony L. Goldberg
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin
| | - Edward D. Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Jeffrey D. Brawn
- Department of Natural Resources and Environmental Sciences, University of Illinois Champaign–Urbana, Urbana, Illinois
| | - Marilyn O. Ruiz
- Department of Pathobiology, University of Illinois Champaign–Urbana, Urbana, Illinois
| | - Uriel Kitron
- Program in Population Biology, Ecology and Evolution, Emory University, Atlanta, Georgia;,Department of Environmental Sciences, Emory University, Atlanta, Georgia
| | - Gonzalo Vazquez-Prokopec
- Program in Population Biology, Ecology and Evolution, Emory University, Atlanta, Georgia;,Department of Environmental Sciences, Emory University, Atlanta, Georgia,Address correspondence to Gonzalo Vazquez-Prokopec, Department of Environmental Sciences, Emory University, 400 Dowman Dr., Math and Science Center, 5th Floor, Suite E530, Atlanta, GA 30322. E-mail:
| |
Collapse
|
3
|
Adelman JS, Tokarz RE, Euken AE, Field EN, Russell MC, Smith RC. Relative Influence of Land Use, Mosquito Abundance, and Bird Communities in Defining West Nile Virus Infection Rates in Culex Mosquito Populations. INSECTS 2022; 13:758. [PMID: 36135459 PMCID: PMC9502061 DOI: 10.3390/insects13090758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/16/2022] [Accepted: 08/21/2022] [Indexed: 06/16/2023]
Abstract
Since its introduction to North America in 1999, the West Nile virus (WNV) has resulted in over 50,000 human cases and 2400 deaths. WNV transmission is maintained via mosquito vectors and avian reservoir hosts, yet mosquito and avian infections are not uniform across ecological landscapes. As a result, it remains unclear whether the ecological communities of the vectors or reservoir hosts are more predictive of zoonotic risk at the microhabitat level. We examined this question in central Iowa, representative of the midwestern United States, across a land use gradient consisting of suburban interfaces with natural and agricultural habitats. At eight sites, we captured mosquito abundance data using New Jersey light traps and monitored bird communities using visual and auditory point count surveys. We found that the mosquito minimum infection rate (MIR) was better predicted by metrics of the mosquito community than metrics of the bird community, where sites with higher proportions of Culex pipiens group mosquitoes during late summer (after late July) showed higher MIRs. Bird community metrics did not significantly influence mosquito MIRs across sites. Together, these data suggest that the microhabitat suitability of Culex vector species is of greater importance than avian community composition in driving WNV infection dynamics at the urban and agricultural interface.
Collapse
Affiliation(s)
- James S. Adelman
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA 50011, USA
- Department of Biological Sciences, The University of Memphis, Memphis, TN 38152, USA
| | - Ryan E. Tokarz
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
- Department of International and Global Health, Mercer University, Macon, GA 31207, USA
| | - Alec E. Euken
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA 50011, USA
| | - Eleanor N. Field
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Marie C. Russell
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Ryan C. Smith
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| |
Collapse
|
4
|
A Comparison of Adult Mosquito Trapping Methods to Assess Potential West Nile Virus Mosquito Vectors in Greece during the Onset of the 2018 Transmission Season. INSECTS 2020; 11:insects11060329. [PMID: 32471294 PMCID: PMC7348707 DOI: 10.3390/insects11060329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/13/2020] [Accepted: 05/25/2020] [Indexed: 11/17/2022]
Abstract
West Nile virus (WNV) threatens the health of humans and equines worldwide. Culex (Cx.) pipiens complex mosquitoes are major vectors but numerous other species have been implicated. Due to variations in blood-feeding behaviour, Cx. pipiens biotypes and hybrids influence transmission, from enzootic cycles (between mosquitoes and birds), to spill-over transmission to humans and equines. In this study, mosquitoes were collected in May–June 2018 during the early period of the transmission season from two regional units of Greece, where WNV cases had been reported in the previous four years (Palaio Faliro and Argolida). A total of 1062 mosquitoes were collected with Biogents Sentinel 2 traps collecting both a greater number of all mosquito species and the Cx. pipiens complex than CDC miniature light traps or Heavy Duty EVS traps. Molecular identification confirmed additional species including Aedes albopictus. The proportion of Cx. pipiens biotypes in Palaio Faliro was 54.5% pipiens, 20.0% molestus and 25.5% hybrids. In Argolida, the collection comprised 68.1% pipiens biotype, 8.3% molestus biotype and 23.6% hybrids. Screening resulted in WNV detection in three females of the pipiens biotype and in one hybrid. As hybrids play a role in spill-over transmission, these findings highlight the importance of entomological surveillance programs incorporating molecular xenomonitoring as an early warning before human cases at the onset of the transmission season.
Collapse
|
5
|
Ribeiro GS, Hamer GL, Diallo M, Kitron U, Ko AI, Weaver SC. Influence of herd immunity in the cyclical nature of arboviruses. Curr Opin Virol 2020; 40:1-10. [PMID: 32193135 PMCID: PMC7434662 DOI: 10.1016/j.coviro.2020.02.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 02/05/2020] [Accepted: 02/13/2020] [Indexed: 12/15/2022]
Abstract
We review and contrast the evidence for an effect of amplifying host herd immunity on circulation and human exposure to arboviruses. Herd immunity of short-lived West Nile virus avian amplifying hosts appears to play a limited role in levels of enzootic circulation and spillover infections of humans, which are not amplifiers. In contrast, herd immunity of nonhuman primate hosts for enzootic Zika, dengue, and chikungunya viruses is much stronger and appears to regulate to a large extent the periodicity of sylvatic amplification in Africa. Following the recent Zika and chikungunya pandemics, human herd immunity in the Americas quickly rose to ∼50% in many regions, although seroprevalence remains patchy. Modeling from decades of chikungunya circulation in Asia suggests that this level of herd immunity will suppress for many years major chikungunya and Zika epidemics in the Americas, followed by smaller outbreaks as herd immunity cycles with a periodicity of up to several decades.
Collapse
Affiliation(s)
- Guilherme S Ribeiro
- Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Rua Waldemar Falcão, 121, Candeal, 40296-710, Salvador, BA, Brazil; Universidade Federal da Bahia, Salvador, Brazil
| | - Gabriel L Hamer
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | | | - Uriel Kitron
- Population Biology, Ecology, and Evolution Graduate Program, Graduate Division of Biological and Biomedical Sciences, Department of Environmental Sciences, Emory University, Atlanta, GA, USA
| | - Albert I Ko
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Scott C Weaver
- World Reference Center for Emerging Viruses and Arboviruses, Institute for Human Infections and Immunity, and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, 77555-0610 TX, USA.
| |
Collapse
|
6
|
Kain MP, Bolker BM. Predicting West Nile virus transmission in North American bird communities using phylogenetic mixed effects models and eBird citizen science data. Parasit Vectors 2019; 12:395. [PMID: 31395085 PMCID: PMC6686473 DOI: 10.1186/s13071-019-3656-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 08/03/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND West Nile virus (WNV) is a mosquito-transmitted disease of birds that has caused bird population declines and can spill over into human populations. Previous research has identified bird species that infect a large fraction of the total pool of infected mosquitoes and correlate with human infection risk; however, these analyses cover small spatial regions and cannot be used to predict transmission in bird communities in which these species are rare or absent. Here we present a mechanistic model for WNV transmission that predicts WNV spread (R0) in any bird community in North America by scaling up from the physiological responses of individual birds to transmission at the level of the community. We predict unmeasured bird species' responses to infection using phylogenetic imputation, based on these species' phylogenetic relationships with bird species with measured responses. RESULTS We focused our analysis on Texas, USA, because it is among the states with the highest total incidence of WNV in humans and is well sampled by birders in the eBird database. Spatio-temporal patterns: WNV transmission is primarily driven by temperature variation across time and space, and secondarily by bird community composition. In Texas, we predicted WNV R0 to be highest in the spring and fall when temperatures maximize the product of mosquito transmission and survival probabilities. In the most favorable months for WNV transmission (April, May, September and October), we predicted R0 to be highest in the "Piney Woods" and "Oak Woods & Prairies" ecoregions of Texas, and lowest in the "High Plains" and "South Texas Brush County" ecoregions. Dilution effect: More abundant bird species are more competent hosts for WNV, and predicted WNV R0 decreases with increasing species richness. Keystone species: We predicted that northern cardinals (Cardinalis cardinalis) are the most important hosts for amplifying WNV and that mourning doves (Zenaida macroura) are the most important sinks of infection across Texas. CONCLUSIONS Despite some data limitations, we demonstrate the power of phylogenetic imputation in predicting disease transmission in heterogeneous host communities. Our mechanistic modeling framework shows promise both for assisting future analyses on transmission and spillover in heterogeneous multispecies pathogen systems and for improving model transparency by clarifying assumptions, choices and shortcomings in complex ecological analyses.
Collapse
Affiliation(s)
- Morgan P. Kain
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1 Canada
| | - Benjamin M. Bolker
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1 Canada
- Department of Mathematics and Statistics, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1 Canada
| |
Collapse
|
7
|
Russell MC, Newton SR, McClure KM, Levine RS, Phelps LP, Lindstrom AB, Strynar MJ. Per- and polyfluoroalkyl substances in two different populations of northern cardinals. CHEMOSPHERE 2019; 222:295-304. [PMID: 30710759 PMCID: PMC6739830 DOI: 10.1016/j.chemosphere.2019.01.112] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 01/15/2019] [Accepted: 01/21/2019] [Indexed: 05/05/2023]
Abstract
The northern cardinal (Cardinalis cardinalis) is a good indicator species for environmental contaminants because it does not migrate and its range covers a diversity of habitats, including metropolitan Atlanta, GA and the geographically isolated Hawaiian Islands. In addition, the cardinal is often found near people's homes, making it likely to be exposed to the same outdoor elements, including soil, groundwater, and air, that surrounding humans experience. In this study, blood serum concentrations of 12 per- and polyfluoroalkyl substances (PFASs) were measured in 40 cardinals from Atlanta and 17 cardinals from the Big Island (Hawaii), HI. We observed significantly higher median concentrations of four PFASs and significantly higher detection frequencies of seven PFASs in the cardinals from Atlanta, relative to the PFAS median concentrations and detection frequencies observed in the cardinals from Hawaii (α = 0.05). Among the PFASs measured, perfluorooctane sulfonate (PFOS) was observed in the highest concentrations. A linear regression model controlling for sex, age, and airport distance did not explain PFOS variation within the Atlanta samples, but a similar model explained 90% of PFOS variation within the Hawaii samples. To our knowledge, these are the first measurements of PFASs in northern cardinals.
Collapse
Affiliation(s)
- Marie C Russell
- Association of Schools and Programs of Public Health, Environmental Health Fellowship Program, Hosted by the Office of the Science Advisor, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
| | - Seth R Newton
- National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Katherine M McClure
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95064, USA
| | - Rebecca S Levine
- Department of Environmental Sciences, Emory University, Atlanta, GA 30322, USA
| | - Lara P Phelps
- Office of the Science Advisor, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Andrew B Lindstrom
- National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Mark J Strynar
- National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| |
Collapse
|
8
|
Long-term surveillance defines spatial and temporal patterns implicating Culex tarsalis as the primary vector of West Nile virus. Sci Rep 2019; 9:6637. [PMID: 31036953 PMCID: PMC6488619 DOI: 10.1038/s41598-019-43246-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/18/2019] [Indexed: 11/08/2022] Open
Abstract
West Nile virus (WNV) has become the most epidemiologically important mosquito-borne disease in the United States, causing ~50,000 cases since its introduction in 1999. Transmitted primarily by Culex species, WNV transmission requires the complex interplay between bird reservoirs and mosquito vectors, with human cases the result of epizootic spillover. To better understand the intrinsic factors that drive these interactions, we have compiled infection data from sentinel chickens, mosquito vectors, and human cases in Iowa over a 15 year period (2002-2016) to better understand the spatial and temporal components that drive WNV transmission. Supplementing these findings with mosquito abundance, distribution, and host preferences data, we provide strong support that Culex tarsalis is the most important vector of human WNV infections in the region. Together, our analysis provides new insights into WNV infection patterns in multiple hosts and highlights the importance of long-term surveillance to understand the dynamics of mosquito-borne-disease transmission.
Collapse
|
9
|
McMillan JR, Blakney RA, Mead DG, Koval WT, Coker SM, Waller LA, Kitron U, Vazquez‐Prokopec GM. Linking the vectorial capacity of multiple vectors to observed patterns of West Nile virus transmission. J Appl Ecol 2019. [DOI: 10.1111/1365-2664.13322] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joseph R. McMillan
- Program in Population Biology, Ecology and EvolutionEmory University Atlanta Georgia
| | | | - Daniel G. Mead
- Southeastern Cooperative Wildlife Disease StudyUniversity of Georgia Athens Georgia
| | - William T. Koval
- Department of Environmental SciencesEmory University Atlanta Georgia
| | - Sarah M. Coker
- Southeastern Cooperative Wildlife Disease StudyUniversity of Georgia Athens Georgia
| | - Lance A. Waller
- Program in Population Biology, Ecology and EvolutionEmory University Atlanta Georgia
- Department of Biostatistics and BioinformaticsRollins School of Public HealthEmory University Atlanta Georgia
| | - Uriel Kitron
- Program in Population Biology, Ecology and EvolutionEmory University Atlanta Georgia
- Department of Environmental SciencesEmory University Atlanta Georgia
| | - Gonzalo M. Vazquez‐Prokopec
- Program in Population Biology, Ecology and EvolutionEmory University Atlanta Georgia
- Department of Environmental SciencesEmory University Atlanta Georgia
| |
Collapse
|
10
|
Talbot B, Ardis M, Kulkarni MA. Influence of Demography, Land Use, and Urban Form on West Nile Virus Risk and Human West Nile Virus Incidence in Ottawa, Canada. Vector Borne Zoonotic Dis 2019; 19:533-539. [PMID: 30615572 DOI: 10.1089/vbz.2018.2366] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human infection by West Nile virus (WNV; family Flaviviridae), in some cases, develops into a deadly neuroinvasive disease. WNV risk is thought to be influenced by factors affecting the density of species that promote replication and transmission of the virus, namely peridomestic bird and mosquito species. Factors influencing contact between peridomestic bird and mosquito species and contact between infected mosquitoes and vulnerable human populations may also be important in determining WNV risk in an area. Several urban form and demographic factors, such as population density and the proportion of aged housing units, have been linked with increased WNV risk. Other factors, such as proportion of old-growth forest and wetlands, have been linked to decreased WNV risk. In this study, we aimed to test the effect of several demographic, land use, and urban form variables on WNV risk within neighborhoods of the city of Ottawa, Canada, based on the spatiotemporal clustering of infected mosquitoes and human WNV cases. We found a large positive effect of population density and proportion of aged housing units on WNV risk, using both entomological and epidemiological data. Interestingly, we found a large negative effect of proportion of natural areas in our epidemiological analysis, but not in our entomological analysis. Although our epidemiological data set was relatively small, these results suggest entomological surveillance results should be interpreted alongside other factors when investigating risk to humans. Our study is also one of the few to suggest an effect of demography, land use, and urban form on WNV risk in a Canadian urban center, using both entomological and epidemiological data.
Collapse
Affiliation(s)
- Benoit Talbot
- 1 School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Mark Ardis
- 2 GDG Environnement, Trois-Rivières, Quebec, Canada
| | - Manisha A Kulkarni
- 1 School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| |
Collapse
|
11
|
Ukawuba I, Shaman J. Association of spring-summer hydrology and meteorology with human West Nile virus infection in West Texas, USA, 2002-2016. Parasit Vectors 2018; 11:224. [PMID: 29618375 PMCID: PMC5885460 DOI: 10.1186/s13071-018-2781-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 03/06/2018] [Indexed: 11/30/2022] Open
Abstract
Background The emergence of West Nile virus (WNV) in the Western Hemisphere has motivated research into the processes contributing to the incidence and persistence of the disease in the region. Meteorology and hydrology are fundamental determinants of vector-borne disease transmission dynamics of a region. The availability of water influences the population dynamics of vector and host, while temperature impacts vector growth rates, feeding habits, and disease transmission potential. Characterization of the temporal pattern of environmental factors influencing WNV risk is crucial to broaden our understanding of local transmission dynamics and to inform efforts of control and surveillance. Methods We used hydrologic, meteorological and WNV data from west Texas (2002–2016) to analyze the relationship between environmental conditions and annual human WNV infection. A Bayesian model averaging framework was used to evaluate the association of monthly environmental conditions with WNV infection. Results Findings indicate that wet conditions in the spring combined with dry and cool conditions in the summer are associated with increased annual WNV cases. Bayesian multi-model inference reveals monthly means of soil moisture, specific humidity and temperature to be the most important variables among predictors tested. Environmental conditions in March, June, July and August were the leading predictors in the best-fitting models. Conclusions The results significantly link soil moisture and temperature in the spring and summer to WNV transmission risk. Wet spring in association with dry and cool summer was the temporal pattern best-describing WNV, regardless of year. Our findings also highlight that soil moisture may be a stronger predictor of annual WNV transmission than rainfall.
Collapse
Affiliation(s)
- Israel Ukawuba
- Mailman School of Public Health, Columbia University, 722 W 168th, New York, NY, 10032, USA.
| | - Jeffrey Shaman
- Mailman School of Public Health, Columbia University, 722 W 168th, New York, NY, 10032, USA
| |
Collapse
|
12
|
Bisanzio D, McMillan JR, Barreto JG, Blitvich BJ, Mead DG, O'Connor J, Kitron U. Evidence for West Nile virus spillover into the squirrel population in Atlanta, Georgia. Vector Borne Zoonotic Dis 2017; 15:303-10. [PMID: 25988439 DOI: 10.1089/vbz.2014.1734] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND In the United States, spillover of West Nile virus (WNV) into wild mammal populations has been reported since the introduction of the virus into the New World in 1999. Eastern gray squirrels (Sciurus carolinensis) exhibit a high seroprevalence for WNV in urban settings where high virus circulation and human spillover have been reported. In Atlanta, Georgia, human cases of WNV are uncommon despite high infection rates in birds and mosquitoes. In this study, we evaluated WNV exposure of eastern gray squirrels in a WNV hot spot in Atlanta. MATERIALS AND METHODS Gray squirrels were live-trapped in Grant Park, Atlanta, during July-October, 2012, and a census was conducted to estimate squirrel density in the study site. Sera from trapped animals were tested for circulating virus-by-virus isolation in cell culture and for WNV-specific antibodies by enzyme-linked immunosorbent assay and plaque reduction neutralization test. Mosquitoes were collected at the same location and tested for virus isolation. RESULTS Among the 69 collected squirrels, 25 (36.2%) tested positive for WNV antibodies, although none were viremic. Seroprevalence was lower in juveniles (18.8%) than in adults (37.5%), but this difference was not statistically significant. Gender and squirrel density had no effect on seroprevalence. Seasonality of squirrel seroprevalence and of mosquito infection were significantly associated, both peaking in August. No difference in squirrel exposure was detected across the collection sites. CONCLUSIONS We report a high degree of WNV exposure in squirrels in Grant Park that was correlated with seasonality of mosquito infection. The detection of antibodies in juveniles suggests that circulation of WNV in the surveyed population is ongoing. Eastern gray squirrels may be suitable indicators for virus amplification and for risk of human spillover on a local scale in urban settings.
Collapse
Affiliation(s)
- Donal Bisanzio
- 1Department of Environmental Sciences, Emory University, Atlanta, Georgia
| | - Joseph R McMillan
- 1Department of Environmental Sciences, Emory University, Atlanta, Georgia
| | - Josafá Gonçalves Barreto
- 2Laboratório de Dermato-Imunologia UEPA/UFPA/Marcello Candia, Marituba, Pará, Brasil.,3Universidade Federal do Pará, Campus Castanhal, Pará, Brasil
| | - Bradley J Blitvich
- 4Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Daniel G Mead
- 5University of Georgia, College of Veterinary Medicine, Southeastern Cooperative Wildlife Disease Study, Athens, Georgia
| | - Josh O'Connor
- 6Fire Management Division, US Fish and Wildlife Service, Atlanta, Georgia
| | - Uriel Kitron
- 1Department of Environmental Sciences, Emory University, Atlanta, Georgia
| |
Collapse
|
13
|
Levine RS, Mead DG, Hamer GL, Brosi BJ, Hedeen DL, Hedeen MW, McMillan JR, Bisanzio D, Kitron UD. Supersuppression: Reservoir Competency and Timing of Mosquito Host Shifts Combine to Reduce Spillover of West Nile Virus. Am J Trop Med Hyg 2016; 95:1174-1184. [PMID: 27503511 DOI: 10.4269/ajtmh.15-0809] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 06/09/2016] [Indexed: 11/07/2022] Open
Abstract
In the eastern United States, human cases of West Nile virus (WNV) result from spillover from urban epizootic transmission between passerine birds and Culex mosquitoes. In Atlanta, GA, substantial WNV presence in hosts and vectors has not resulted in the human disease burden observed in cities with similar infection pressure. Our study goal was to investigate extrinsic ecological conditions that potentially contribute to these reduced transmission rates. We conducted WNV surveillance among hosts and vectors in urban Atlanta and recorded an overall avian seroprevalence of nearly 30%, which was significantly higher among northern cardinals, blue jays, and members of the mimid family, and notably low among American robins. Examination of temporal Culex feeding patterns showed a marked feeding shift from American robins in the early season to northern cardinals in the late season. We therefore rule out American robins as superspreaders in the Atlanta area and suggest instead that northern cardinals and mimids act as WNV "supersuppressor" species, which slow WNV transmission by drawing many infectious bites during the critical virus amplification period, yet failing to amplify transmission due to low host competencies. Of particular interest, urban forest patches provide spillover protection by increasing the WNV amplification fraction on supersuppressor species.
Collapse
Affiliation(s)
- Rebecca S Levine
- Department of Environmental Sciences, Emory University, Atlanta, Georgia.
| | - Daniel G Mead
- Southeastern Cooperative Wildlife Disease Study, University of Georgia College of Veterinary Medicine, Athens, Georgia
| | - Gabriel L Hamer
- Department of Entomology, Texas A&M College of Agriculture and Life Sciences, Texas A&M University, College Station, Texas
| | - Berry J Brosi
- Department of Environmental Sciences, Emory University, Atlanta, Georgia
| | - David L Hedeen
- Office of Environmental Services, Georgia Department of Transportation, Atlanta, Georgia
| | - Meghan W Hedeen
- Office of Environmental Services, Georgia Department of Transportation, Atlanta, Georgia
| | - Joseph R McMillan
- Department of Environmental Sciences, Emory University, Atlanta, Georgia
| | - Donal Bisanzio
- Department of Environmental Sciences, Emory University, Atlanta, Georgia
| | - Uriel D Kitron
- Department of Environmental Sciences, Emory University, Atlanta, Georgia
| |
Collapse
|
14
|
Vazquez-Prokopec GM, Perkins TA, Waller LA, Lloyd AL, Reiner RC, Scott TW, Kitron U. Coupled Heterogeneities and Their Impact on Parasite Transmission and Control. Trends Parasitol 2016; 32:356-367. [PMID: 26850821 PMCID: PMC4851872 DOI: 10.1016/j.pt.2016.01.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 12/19/2015] [Accepted: 01/05/2016] [Indexed: 12/17/2022]
Abstract
Most host-parasite systems exhibit remarkable heterogeneity in the contribution to transmission of certain individuals, locations, host infectious states, or parasite strains. While significant advancements have been made in the understanding of the impact of transmission heterogeneity in epidemic dynamics and parasite persistence and evolution, the knowledge base of the factors contributing to transmission heterogeneity is limited. We argue that research efforts should move beyond considering the impact of single sources of heterogeneity and account for complex couplings between conditions with potential synergistic impacts on parasite transmission. Using theoretical approaches and empirical evidence from various host-parasite systems, we investigate the ecological and epidemiological significance of couplings between heterogeneities and discuss their potential role in transmission dynamics and the impact of control.
Collapse
Affiliation(s)
- Gonzalo M Vazquez-Prokopec
- Department of Environmental Sciences, Emory University, Atlanta, GA, USA; Fogarty International Center, National Institutes of Health, Bethesda, MD, USA.
| | - T Alex Perkins
- Fogarty International Center, National Institutes of Health, Bethesda, MD, USA; Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Lance A Waller
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Alun L Lloyd
- Fogarty International Center, National Institutes of Health, Bethesda, MD, USA; Biomathematics Graduate Program and Department of Mathematics, North Carolina State University, Raleigh, NC, USA
| | - Robert C Reiner
- Fogarty International Center, National Institutes of Health, Bethesda, MD, USA; Department of Epidemiology and Biostatistics, Indiana University, Bloomington, IN, USA
| | - Thomas W Scott
- Fogarty International Center, National Institutes of Health, Bethesda, MD, USA; Department of Entomology and Nematology, University of California Davis, Davis, CA, USA
| | - Uriel Kitron
- Department of Environmental Sciences, Emory University, Atlanta, GA, USA; Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
15
|
Abstract
Antibody duration, following a humoral immune response to West Nile virus (WNV) infection, is poorly understood in free-ranging avian hosts. Quantifying antibody decay rate is important for interpreting serologic results and for understanding the potential for birds to serorevert and become susceptible again. We sampled free-ranging birds in Chicago, Illinois, US, from 2005 to 2011 and Atlanta, Georgia, US, from 2010 to 2012 to examine the dynamics of antibody decay following natural WNV infection. Using serial dilutions in a blocking enzyme-linked immunosorbent assay, we quantified WNV antibody titer in repeated blood samples from individual birds over time. We quantified a rate of antibody decay for 23 Northern Cardinals (Cardinalis cardinalis) of 0.198 natural log units per month and 24 individuals of other bird species of 0.178 natural log units per month. Our results suggest that juveniles had a higher rate of antibody decay than adults, which is consistent with nonlinear antibody decay at different times postexposure. Overall, most birds had undetectable titers 2 yr postexposure. Nonuniform WNV antibody decay rates in free-ranging birds underscore the need for cautious interpretation of avian serology results in the context of arbovirus surveillance and epidemiology.
Collapse
|
16
|
Manore CA, Davis JK, Christofferson RC, Wesson DM, Hyman JM, Mores CN. Towards an early warning system for forecasting human west nile virus incidence. PLOS CURRENTS 2014; 6:ecurrents.outbreaks.f0b3978230599a56830ce30cb9ce0500. [PMID: 25914857 PMCID: PMC4398566 DOI: 10.1371/currents.outbreaks.f0b3978230599a56830ce30cb9ce0500] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have identified environmental and demographic variables, available in January, that predict the relative magnitude and spatial distribution of West Nile virus (WNV) for the following summer. The yearly magnitude and spatial distribution for WNV incidence in humans in the United States (US) have varied wildly in the past decade. Mosquito control measures are expensive and having better estimates of the expected relative size of a future WNV outbreak can help in planning for the mitigation efforts and costs. West Nile virus is spread primarily between mosquitoes and birds; humans are an incidental host. Previous efforts have demonstrated a strong correlation between environmental factors and the incidence of WNV. A predictive model for human cases must include both the environmental factors for the mosquito-bird epidemic and an anthropological model for the risk of humans being bitten by a mosquito. Using weather data and demographic data available in January for every county in the US, we use logistic regression analysis to predict the probability that the county will have at least one WNV case the following summer. We validate our approach and the spatial and temporal WNV incidence in the US from 2005 to 2013. The methodology was applied to forecast the 2014 WNV incidence in late January 2014. We find the most significant predictors for a county to have a case of WNV to be the mean minimum temperature in January, the deviation of this minimum temperature from the expected minimum temperature, the total population of the county, publicly available samples of local bird populations, and if the county had a case of WNV the previous year.
Collapse
Affiliation(s)
- Carrie A Manore
- Center for Computational Science, Tulane University, New Orleans, Louisiana, USA
| | - Justin K Davis
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
| | | | - Dawn M Wesson
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
| | - James M Hyman
- Department of Mathematics, Tulane University, New Orleans, Louisiana, USA
| | - Christopher N Mores
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
| |
Collapse
|
17
|
Manore CA, Davis J, Christofferson RC, Wesson D, Hyman JM, Mores CN. Towards an early warning system for forecasting human west nile virus incidence. PLOS CURRENTS 2014; 6:ecurrents.outbreaks.ed6f0f8a61d20ae5f32aaa5c2b8d3c23. [PMID: 24611126 PMCID: PMC3945055 DOI: 10.1371/currents.outbreaks.ed6f0f8a61d20ae5f32aaa5c2b8d3c23] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have identified environmental and demographic variables, available in January, that predict the relative magnitude and spatial distribution of West Nile virus (WNV) for the following summer. The yearly magnitude and spatial distribution for WNV incidence in humans in the United States (US) have varied wildly in the past decade. Mosquito control measures are expensive and having better estimates of the expected relative size of a future WNV outbreak can help in planning for the mitigation efforts and costs. West Nile virus is spread primarily between mosquitoes and birds; humans are an incidental host. Previous efforts have demonstrated a strong correlation between environmental factors and the incidence of WNV. A predictive model for human cases must include both the environmental factors for the mosquito-bird epidemic and an anthropological model for the risk of humans being bitten by a mosquito. Using weather data and demographic data available in January for every county in the US, we use logistic regression analysis to predict the probability that the county will have at least one WNV case the following summer. We validate our approach and the spatial and temporal WNV incidence in the US from 2005 to 2013. The methodology was applied to forecast the 2014 WNV incidence in late January 2014. We find the most significant predictors for a county to have a case of WNV to be the mean minimum temperature in January, the deviation of this minimum temperature from the expected minimum temperature, the total population of the county, publicly available samples of local bird populations, and if the county had a case of WNV the previous year.
Collapse
Affiliation(s)
- Carrie A Manore
- Center for Computational Science, Tulane University, New Orleans, Louisiana, USA
| | - Justin Davis
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
| | | | - Dawn Wesson
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
| | - James M Hyman
- Department of Mathematics, Tulane University, New Orleans, Louisiana, USA
| | - Christopher N Mores
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
| |
Collapse
|