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Zubair AS, McAlpine LS, Gobeske KT. Virology, ecology, epidemiology, pathology, and treatment of eastern equine encephalitis. J Neurol Sci 2024; 457:122886. [PMID: 38278094 DOI: 10.1016/j.jns.2024.122886] [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] [Received: 10/06/2023] [Revised: 12/27/2023] [Accepted: 01/11/2024] [Indexed: 01/28/2024]
Abstract
Eastern equine encephalitis (EEE) was one of the first-recognized neuroinvasive arboviral diseases in North America, and it remains the most lethal. Although EEE is known to have periodic spikes in infection rates, there is increasing evidence that it may be undergoing a change in its prevalence and its public health burden. Numerous factors shape the scope of EEE in humans, and there are important similarities with other emergent viral diseases that have surfaced or strengthened in recent years. Because environmental and ecological conditions that broadly influence the epidemiology of arboviral diseases also are changing, and the frequency, severity, and scope of outbreaks are expected to worsen, an expanded understanding of EEE will have untold importance in coming years. Here we review the factors shaping EEE transmission cycles and the conditions leading to outbreaks in humans from an updated, multidomain perspective. We also provide special consideration of factors shaping the virology, host-vector-environment relationships, and mechanisms of pathology and treatment as a reference for broadening audiences.
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Affiliation(s)
- Adeel S Zubair
- Department of Neurology, Yale School of Medicine, New Haven, CT, USA
| | | | - Kevin T Gobeske
- Department of Neurology, Yale School of Medicine, New Haven, CT, USA.
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2
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Hill V, Koch RT, Bialosuknia SM, Ngo K, Zink SD, Koetzner CA, Maffei JG, Dupuis AP, Backenson PB, Oliver J, Bransfield AB, Misencik MJ, Petruff TA, Shepard JJ, Warren JL, Gill MS, Baele G, Vogels CBF, Gallagher G, Burns P, Hentoff A, Smole S, Brown C, Osborne M, Kramer LD, Armstrong PM, Ciota AT, Grubaugh ND. Dynamics of eastern equine encephalitis virus during the 2019 outbreak in the Northeast United States. Curr Biol 2023:S0960-9822(23)00679-6. [PMID: 37295427 DOI: 10.1016/j.cub.2023.05.047] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 05/04/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023]
Abstract
Eastern equine encephalitis virus (EEEV) causes a rare but severe disease in horses and humans and is maintained in an enzootic transmission cycle between songbirds and Culiseta melanura mosquitoes. In 2019, the largest EEEV outbreak in the United States for more than 50 years occurred, centered in the Northeast. To explore the dynamics of the outbreak, we sequenced 80 isolates of EEEV and combined them with existing genomic data. We found that, similar to previous years, cases were driven by multiple independent but short-lived virus introductions into the Northeast from Florida. Once in the Northeast, we found that Massachusetts was important for regional spread. We found no evidence of any changes in viral, human, or bird factors which would explain the increase in cases in 2019, although the ecology of EEEV is complex and further data is required to explore these in more detail. By using detailed mosquito surveillance data collected by Massachusetts and Connecticut, however, we found that the abundance of Cs. melanura was exceptionally high in 2019, as was the EEEV infection rate. We employed these mosquito data to build a negative binomial regression model and applied it to estimate early season risks of human or horse cases. We found that the month of first detection of EEEV in mosquito surveillance data and vector index (abundance multiplied by infection rate) were predictive of cases later in the season. We therefore highlight the importance of mosquito surveillance programs as an integral part of public health and disease control.
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Affiliation(s)
- Verity Hill
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA.
| | - Robert T Koch
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Sean M Bialosuknia
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, Slingerlands, NY 12159, USA
| | - Kiet Ngo
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, Slingerlands, NY 12159, USA
| | - Steven D Zink
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, Slingerlands, NY 12159, USA
| | - Cheri A Koetzner
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, Slingerlands, NY 12159, USA
| | - Joseph G Maffei
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, Slingerlands, NY 12159, USA
| | - Alan P Dupuis
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, Slingerlands, NY 12159, USA
| | - P Bryon Backenson
- New York State Department of Health, Bureau of Communicable Disease Control, Albany, NY 12237, USA
| | - JoAnne Oliver
- New York State Department of Health, Bureau of Communicable Disease Control, Syracuse, NY 13202, USA; Division of Environmental and Renewable Resources, State University of New York at Morrisville - School of Agriculture, Business and Technology, Morrisville, NY 13408, USA
| | - Angela B Bransfield
- Center for Vector Biology and Zoonotic Diseases, Department of Entomology, The Connecticut Agricultural Experiment Station, New Haven, CT 06511, USA
| | - Michael J Misencik
- Center for Vector Biology and Zoonotic Diseases, Department of Entomology, The Connecticut Agricultural Experiment Station, New Haven, CT 06511, USA
| | - Tanya A Petruff
- Center for Vector Biology and Zoonotic Diseases, Department of Entomology, The Connecticut Agricultural Experiment Station, New Haven, CT 06511, USA
| | - John J Shepard
- Center for Vector Biology and Zoonotic Diseases, Department of Entomology, The Connecticut Agricultural Experiment Station, New Haven, CT 06511, USA
| | - Joshua L Warren
- Department of Biostatistics, Yale School of Public Health, New Haven, CT 06510, USA; Public Health Modeling Unit, Yale School of Public Health, New Haven, CT 06510, USA
| | - Mandev S Gill
- Department of Statistics, University of Georgia, Athens, GA 30602, USA
| | - Guy Baele
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Leuven BE-3000, Belgium
| | - Chantal B F Vogels
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Glen Gallagher
- Massachusetts Department of Public Health, Boston, MA 02108, USA; Rhode Island State Health Laboratory, Rhode Island Department of Health, Providence, RI 02904, USA
| | - Paul Burns
- Massachusetts Department of Public Health, Boston, MA 02108, USA
| | - Aaron Hentoff
- Massachusetts Department of Public Health, Boston, MA 02108, USA
| | - Sandra Smole
- Massachusetts Department of Public Health, Boston, MA 02108, USA
| | - Catherine Brown
- Massachusetts Department of Public Health, Boston, MA 02108, USA
| | - Matthew Osborne
- Massachusetts Department of Public Health, Boston, MA 02108, USA
| | - Laura D Kramer
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, Slingerlands, NY 12159, USA; Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY 12237, USA
| | - Philip M Armstrong
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA; Division of Environmental and Renewable Resources, State University of New York at Morrisville - School of Agriculture, Business and Technology, Morrisville, NY 13408, USA.
| | - Alexander T Ciota
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, Slingerlands, NY 12159, USA; Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY 12237, USA.
| | - Nathan D Grubaugh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA; Department of Biostatistics, Yale School of Public Health, New Haven, CT 06510, USA; Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA.
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3
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Hill V, Koch RT, Bialosuknia SM, Ngo K, Zink SD, Koetzner CA, Maffei JG, Dupuis AP, Backenson PB, Oliver J, Bransfield AB, Misencik MJ, Petruff TA, Shepard JJ, Warren JL, Gill MS, Baele G, Vogels CBF, Gallagher G, Burns P, Hentoff A, Smole S, Brown C, Osborne M, Kramer LD, Armstrong PM, Ciota AT, Grubaugh ND. Dynamics of Eastern equine encephalitis virus during the 2019 outbreak in the Northeast United States. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.03.06.23286851. [PMID: 36945576 PMCID: PMC10029029 DOI: 10.1101/2023.03.06.23286851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Eastern equine encephalitis virus (EEEV) causes a rare but severe disease in horses and humans, and is maintained in an enzootic transmission cycle between songbirds and Culiseta melanura mosquitoes. In 2019, the largest EEEV outbreak in the United States for more than 50 years occurred, centered in the Northeast. To explore the dynamics of the outbreak, we sequenced 80 isolates of EEEV and combined them with existing genomic data. We found that, like previous years, cases were driven by frequent short-lived virus introductions into the Northeast from Florida. Once in the Northeast, we found that Massachusetts was important for regional spread. We found no evidence of any changes in viral, human, or bird factors which would explain the increase in cases in 2019. By using detailed mosquito surveillance data collected by Massachusetts and Connecticut, however, we found that the abundance of Cs. melanura was exceptionally high in 2019, as was the EEEV infection rate. We employed these mosquito data to build a negative binomial regression model and applied it to estimate early season risks of human or horse cases. We found that the month of first detection of EEEV in mosquito surveillance data and vector index (abundance multiplied by infection rate) were predictive of cases later in the season. We therefore highlight the importance of mosquito surveillance programs as an integral part of public health and disease control.
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Armstrong PM, Andreadis TG. Ecology and Epidemiology of Eastern Equine Encephalitis Virus in the Northeastern United States: An Historical Perspective. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:1-13. [PMID: 34734628 PMCID: PMC8755988 DOI: 10.1093/jme/tjab077] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Indexed: 05/10/2023]
Abstract
In the current review, we examine the regional history, ecology, and epidemiology of eastern equine encephalitis virus (EEEV) to investigate the major drivers of disease outbreaks in the northeastern United States. EEEV was first recognized as a public health threat during an outbreak in eastern Massachusetts in 1938, but historical evidence for equine epizootics date back to the 1800s. Since then, sporadic disease outbreaks have reoccurred in the Northeast with increasing frequency and northward expansion of human cases during the last 20 yr. Culiseta melanura (Coquillett) (Diptera: Culicidae) serves as the main enzootic vector that drives EEEV transmission among wild birds, but this mosquito species will occasionally feed on mammals. Several species have been implicated as bridge vectors to horses and humans, with Coquilletstidia perturbans (Walker) as a leading suspect based on its opportunistic feeding behavior, vector competence, and high infection rates during recent disease outbreaks. A diversity of bird species are reservoir competent, exposed to EEEV, and serve as hosts for Cs. melanura, with a few species, including the wood thrush (Hlocichia mustelina) and the American robin (Turdus migratorius), contributing disproportionately to virus transmission based on available evidence. The major factors responsible for the sustained resurgence of EEEV are considered and may be linked to regional landscape and climate changes that support higher mosquito densities and more intense virus transmission.
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Affiliation(s)
- Philip M Armstrong
- Center for Vector Biology and Zoonotic Diseases, Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, P.O. Box 1106. 123 Huntington Street, New Haven, CT 06504, USA
| | - Theodore G Andreadis
- Center for Vector Biology and Zoonotic Diseases, Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, P.O. Box 1106. 123 Huntington Street, New Haven, CT 06504, USA
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Burkett-Cadena ND, Day JF, Unnasch TR. Ecology of Eastern Equine Encephalitis Virus in the Southeastern United States: Incriminating Vector and Host Species Responsible for Virus Amplification, Persistence, and Dispersal. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:41-48. [PMID: 34734635 DOI: 10.1093/jme/tjab076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Indexed: 06/13/2023]
Abstract
Eastern equine encephalitis virus (EEEV; family Togaviridae, genus Alphavirus) is a mosquito-borne pathogen found in eastern North America that causes severe disease in humans and horses. The mosquito Culiseta melanura (Coquillett) (Diptera: Culicidae) is the primary enzootic vector of EEEV throughout eastern North America while several mosquito species belonging to diverse genera serve as bridge vectors. The ecology of EEEV differs between northern and southern foci, with respect to phenology of outbreaks, important vertebrate hosts, and bridge vector species. Active transmission is limited to roughly half of the year in northern foci (New York, New Hampshire, Massachusetts, Connecticut), while year-round transmission occurs in the southeastern region (particularly Florida). Multiple phylogenetic analyses indicate that EEEV strains circulating in northern foci are likely transported from southern foci by migrating birds. Bird species that overwinter or migrate through Florida, are bitten by Cs. melanura in late spring, and arrive at northern breeding grounds in May are the most likely candidates to disperse EEEV northward. Available data indicate that common yellowthroat and green heron satisfy these criteria and could serve as virus dispersers. Understanding the factors that drive the phenology of Cs. melanura reproduction in the south and the timing of avian migration from southern foci could provide insight into how confluence of these biological phenomena shapes outbreaks of EEE throughout its range. This information could be used to develop models predicting the likelihood of outbreaks in a given year, allowing vector control districts to more efficiently marshal resources necessary to protect their stakeholders.
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Affiliation(s)
- Nathan D Burkett-Cadena
- Florida Medical Entomology Laboratory, University of Florida IFAS, 200 9th Street SE, Vero Beach, FL 32962, USA
| | - Jonathan F Day
- Florida Medical Entomology Laboratory, University of Florida IFAS, 200 9th Street SE, Vero Beach, FL 32962, USA
| | - Thomas R Unnasch
- Center for Global Health Infectious Disease Research, University of South Florida, 3720 Spectrum Blvd., Suite 304, Tampa, FL 33612, USA
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Bellekom B, Hackett TD, Lewis OT. A Network Perspective on the Vectoring of Human Disease. Trends Parasitol 2021; 37:391-400. [PMID: 33419670 DOI: 10.1016/j.pt.2020.12.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/25/2020] [Accepted: 12/01/2020] [Indexed: 12/25/2022]
Abstract
Blood-sucking insects are important vectors of disease, with biting Diptera (flies) alone transmitting diseases that cause an estimated 700 000 human deaths a year. Insect vectors also bite nonhuman hosts, linking them into host-biting networks. While the major vectors of prominent diseases, such as malaria, yellow fever, dengue, and Zika, are intensively studied, there has been limited focus on the wider interactions of biting insects with nonhuman hosts. Drawing on network analysis and visualisation approaches from food-web ecology, we discuss the value of a network perspective for understanding host-insect-disease interactions, with a focus on Diptera vectors. Potential applications include highlighting pathways of disease transmission, highlighting reservoirs of infection, and identifying emerging and previously unrecognised vectors.
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Affiliation(s)
- Ben Bellekom
- Department of Zoology, 11a Mansfield Road, Oxford OX1 3SZ, UK.
| | - Talya D Hackett
- Department of Zoology, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Owen T Lewis
- Department of Zoology, 11a Mansfield Road, Oxford OX1 3SZ, UK
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Petruff TA, McMillan JR, Shepard JJ, Andreadis TG, Armstrong PM. Increased mosquito abundance and species richness in Connecticut, United States 2001-2019. Sci Rep 2020; 10:19287. [PMID: 33159108 PMCID: PMC7648108 DOI: 10.1038/s41598-020-76231-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/22/2020] [Indexed: 12/04/2022] Open
Abstract
Historical declines in multiple insect taxa have been documented across the globe in relation to landscape-level changes in land use and climate. However, declines have either not been universally observed in all regions or examined for all species. Because mosquitoes are insects of public health importance, we analyzed a longitudinal mosquito surveillance data set from Connecticut (CT), United States (U.S.) from 2001 to 2019 to identify changes in mosquito community composition over time. We first analyzed annual site-level collections and metrics of mosquito community composition with generalized linear/additive mixed effects models; we also examined annual species-level collections using the same tools. We then examined correlations between statewide collections and weather variables as well as site-level collections and land cover classifications. We found evidence that the average trap night collection of mosquitoes has increased by ~ 60% and statewide species richness has increased by ~ 10% since 2001. Total species richness was highest in the southern portion of CT, likely due to the northward range expansion of multiple species within the Aedes, Anopheles, Culex, and Psorophora genera. How the expansion of mosquito populations in the northeast U.S. will alter mosquito-borne pathogen transmission in the region will require further investigation.
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Affiliation(s)
- Tanya A Petruff
- Center for Vector Biology and Zoonotic Diseases, Environmental Sciences, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA
| | - Joseph R McMillan
- Center for Vector Biology and Zoonotic Diseases, Environmental Sciences, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA.
| | - John J Shepard
- Center for Vector Biology and Zoonotic Diseases, Environmental Sciences, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA
| | - Theodore G Andreadis
- Center for Vector Biology and Zoonotic Diseases, Environmental Sciences, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA
| | - Philip M Armstrong
- Center for Vector Biology and Zoonotic Diseases, Environmental Sciences, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA
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West RG, Mathias DR, Day JF, Boohene CK, Unnasch TR, Burkett-Cadena ND. Vectorial Capacity of Culiseta melanura (Diptera: Culicidae) Changes Seasonally and Is Related to Epizootic Transmission of Eastern Equine Encephalitis Virus in Central Florida. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00270] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Azar SR, Campos RK, Bergren NA, Camargos VN, Rossi SL. Epidemic Alphaviruses: Ecology, Emergence and Outbreaks. Microorganisms 2020; 8:microorganisms8081167. [PMID: 32752150 PMCID: PMC7464724 DOI: 10.3390/microorganisms8081167] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/23/2020] [Accepted: 07/28/2020] [Indexed: 12/13/2022] Open
Abstract
Over the past century, the emergence/reemergence of arthropod-borne zoonotic agents has been a growing public health concern. In particular, agents from the genus Alphavirus pose a significant risk to both animal and human health. Human alphaviral disease presents with either arthritogenic or encephalitic manifestations and is associated with significant morbidity and/or mortality. Unfortunately, there are presently no vaccines or antiviral measures approved for human use. The present review examines the ecology, epidemiology, disease, past outbreaks, and potential to cause contemporary outbreaks for several alphavirus pathogens.
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Affiliation(s)
- Sasha R. Azar
- Department of Pathology, The University of Texas Medical Branch, Galveston, TX 77555-0609, USA;
| | - Rafael K. Campos
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX 77555-0609, USA;
| | | | - Vidyleison N. Camargos
- Host-Microorganism Interaction Lab, Department of Microbiology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil;
| | - Shannan L. Rossi
- Department of Pathology, The University of Texas Medical Branch, Galveston, TX 77555-0609, USA;
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, TX 77555-0610, USA
- Correspondence: ; Tel.: +409-772-9033
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Dynamics of prevalence and distribution pattern of avian Plasmodium species and its vectors in diverse zoogeographical areas - A review. INFECTION GENETICS AND EVOLUTION 2020; 81:104244. [PMID: 32087345 DOI: 10.1016/j.meegid.2020.104244] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/04/2020] [Accepted: 02/14/2020] [Indexed: 12/18/2022]
Abstract
Avian Plasmodium is of special interest to health care scientists and veterinarians due to the potency of causing avian malaria in non-adapted birds and their evolutionary phylogenetic relationship with human malaria species. This article aimed to provide a comprehensive list of the common avian Plasmodium parasites in the birds and mosquitoes, to specify the common Plasmodium species and lineages in the selected regions of West of Asia, East of Europe, and North of Africa/Middle East, and to determine the contribution of generalist and host-specific Plasmodium species and lineages. The final list of published infected birds includes 146 species, among which Passer domesticus was the most prevalent in the studied areas. The species of Acrocephalus arundinaceus and Sylvia atricapilla were reported as common infected hosts in the examined regions of three continents. The highest numbers of common species of infected birds between continent pairs were from Asia and Europe, and no common record was found from Europe and Africa. The species of Milvus migrans and Upupa epops were recorded as common species from Asia and Africa. The lineage of GRW11 and species of P. relictum were the most prevalent parasites among all the infection records in birds. The most prevalent genus of vectors of avian malaria belonged to Culex and species of Cx. pipiens. The lineage SGS1 with the highest number of occurrence has been found in various vectors comprising Cx. pipiens, Cx. modestus, Cx. theileri, Cx. sasai, Cx. perexiguus, Lutzia vorax, and Culicoides alazanicus. A total of 31 Plasmodium species and 59 Plasmodium lineages were recorded from these regions. SGS1, GRW04, and GRW11, and P. relictum and P. vaughani are specified as common generalist avian malaria parasites from these three geographic areas. The presence of avian Plasmodium parasites in distant geographic areas and various hosts may be explained by the movement of the infected birds through the migration routes. Although most recorded lineages were from Asia, investigating the distribution of lineages in some of the countries has not been done. Thus, the most important outcome of this review is the determination of the distribution pattern of parasite and vector species that shed light on gaps requiring further studies on the monitoring of avian Plasmodium and common vectors extension. This task could be achieved through scientific field and laboratory networking, performing active surveillance and designing regional/continental control programs of birds' malaria and other zoonotic diseases.
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McMillan JR, Armstrong PM, Andreadis TG. Patterns of mosquito and arbovirus community composition and ecological indexes of arboviral risk in the northeast United States. PLoS Negl Trop Dis 2020; 14:e0008066. [PMID: 32092063 PMCID: PMC7058363 DOI: 10.1371/journal.pntd.0008066] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 03/05/2020] [Accepted: 01/15/2020] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND In the northeast United States (U.S.), mosquitoes transmit a number of arboviruses, including eastern equine encephalitis, Jamestown Canyon, and West Nile that pose an annual threat to human and animal health. Local transmission of each arbovirus may be driven by the involvement of multiple mosquito species; however, the specificity of these vector-virus associations has not been fully quantified. METHODOLOGY We used long-term surveillance data consistently collected over 18 years to evaluate mosquito and arbovirus community composition in the State of Connecticut (CT) based on land cover classifications and mosquito species-specific natural histories using community ecology approaches available in the R package VEGAN. We then used binomial-error generalized linear mixed effects models to quantify species-specific trends in arbovirus detections. PRIMARY RESULTS The composition of mosquito communities throughout CT varied more among sites than among years, with variation in mosquito community composition among sites explained mostly by a forested-to-developed-land-cover gradient. Arboviral communities varied equally among sites and years, and only developed and forested wetland land cover classifications were associated with the composition of arbovirus detections among sites. Overall, the avian host arboviruses, mainly West Nile and eastern equine encephalitis, displayed the most specific associations among mosquito species and sites, while in contrast, the mammalian host arboviruses (including Cache Valley, Jamestown Canyon, and Potosi) associated with a more diverse mix of mosquito species and were widely distributed throughout CT. CONCLUSIONS We find that avian arboviruses act as vector specialists infecting a few key mosquito species that associate with discrete habitats, while mammalian arboviruses are largely vector generalists infecting a wide diversity of mosquito species and habitats in the region. These distinctions have important implications for the design and implementation of mosquito and arbovirus surveillance programs as well as mosquito control efforts.
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Affiliation(s)
- Joseph R. McMillan
- Environmental Sciences, Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
| | - Philip M. Armstrong
- Environmental Sciences, Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
| | - Theodore G. Andreadis
- Environmental Sciences, Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
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Sindbis virus polyarthritis outbreak signalled by virus prevalence in the mosquito vectors. PLoS Negl Trop Dis 2019; 13:e0007702. [PMID: 31465453 PMCID: PMC6738656 DOI: 10.1371/journal.pntd.0007702] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 09/11/2019] [Accepted: 08/13/2019] [Indexed: 11/19/2022] Open
Abstract
Polyarthritis and rash caused by Sindbis virus (SINV), was first recognised in northern Europe about 50 years ago and is known as Ockelbo disease in Sweden and Pogosta disease in Finland. This mosquito-borne virus occurs mainly in tropical and sub-tropical countries, and in northern Europe it is suggested to cause regularly reoccurring outbreaks. Here a seven-year cycle of SINV outbreaks has been referred to in scientific papers, although the hypothesis is based solely on reported human cases. In the search for a more objective outbreak signal, we evaluated mosquito abundance and SINV prevalence in vector mosquitoes from an endemic area in central Sweden. Vector mosquitoes collected in the River Dalälven floodplains during the years before, during, and after the hypothesised 2002 outbreak year were assayed for virus on cell culture. Obtained isolates were partially sequenced, and the nucleotide sequences analysed using Bayesian maximum clade credibility and median joining network analysis. Only one SINV strain was recovered in 2001, and 4 strains in 2003, while 15 strains were recovered in 2002 with significantly increased infection rates in both the enzootic and the bridge-vectors. In 2002, the Maximum Likelihood Estimated infection rates were 10.0/1000 in the enzootic vectors Culex torrentium/pipiens, and 0.62/1000 in the bridge-vector Aedes cinereus, compared to 4.9/1000 and 0.0/1000 in 2001 and 0.0/1000 and 0.32/1000 in 2003 Sequence analysis showed that all isolates belonged to the SINV genotype I (SINV-I). The genetic analysis revealed local maintenance of four SINV-I clades in the River Dalälven floodplains over the years. Our findings suggest that increased SINV-I prevalence in vector mosquitoes constitutes the most valuable outbreak marker for further scrutinising the hypothesized seven-year cycle of SINV-I outbreaks and the mechanisms behind.
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Heberlein-Larson LA, Tan Y, Stark LM, Cannons AC, Shilts MH, Unnasch TR, Das SR. Complex Epidemiological Dynamics of Eastern Equine Encephalitis Virus in Florida. Am J Trop Med Hyg 2019; 100:1266-1274. [PMID: 30860014 PMCID: PMC6493969 DOI: 10.4269/ajtmh.18-0783] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/07/2019] [Indexed: 11/07/2022] Open
Abstract
Eastern equine encephalitis virus (EEEV) infection results in high mortality in infected horses and humans. Florida has been identified as an important source of EEEV epidemics to other states in the United States. In this study, we further characterized the epidemiological and evolutionary dynamics of EEEV in Florida. Epidemiological analysis of sentinel chicken seroconversion rates to EEEV infections during 2005-2016 suggested significant seasonality of EEEV activity in Florida. We observed significant annual activity of EEEV in the North and North Central regions, with little significant seasonality in the Panhandle region. Phylogenetic analysis of complete EEEV genome sequences from different host sources and regions in Florida during 1986-2014 revealed extensive genetic diversity and spatial dispersal of the virus within Florida and relatively more clustering of the viruses in the Panhandle region. We found no significant association between EEEV genetic variation and host source. Overall, our study revealed a complex epidemiological dynamic of EEEV within Florida, implicating the Panhandle region as a possible source of the virus with sustained year-round transmission. These findings will help in implementing targeted control measures that can have the most impact in reducing or eliminating EEEV and other mosquito-borne viral infections within Florida and in the rest of the United States.
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Affiliation(s)
- Lea A. Heberlein-Larson
- Florida Department of Health, Bureau of Public Health Laboratories, Tampa, Florida
- Global Health Infectious Disease Research Program, Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida
| | - Yi Tan
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Lillian M. Stark
- Florida Department of Health, Bureau of Public Health Laboratories, Tampa, Florida
| | - Andrew C. Cannons
- Florida Department of Health, Bureau of Public Health Laboratories, Tampa, Florida
| | - Meghan H. Shilts
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Thomas R. Unnasch
- Global Health Infectious Disease Research Program, Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida
| | - Suman R. Das
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
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Soghigian J, Andreadis TG, Molaei G. Population genomics of Culiseta melanura, the principal vector of Eastern equine encephalitis virus in the United States. PLoS Negl Trop Dis 2018; 12:e0006698. [PMID: 30118494 PMCID: PMC6114928 DOI: 10.1371/journal.pntd.0006698] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 08/29/2018] [Accepted: 07/17/2018] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Eastern Equine Encephalitis (EEE) (Togaviridae, Alphavirus) is a highly pathogenic mosquito-borne arbovirus that circulates in an enzootic cycle involving Culiseta melanura mosquitoes and wild Passeriformes birds in freshwater swamp habitats. Recently, the northeastern United States has experienced an intensification of virus activity with increased human involvement and northward expansion into new regions. In addition to its principal role in enzootic transmission of EEE virus among avian hosts, recent studies on the blood-feeding behavior of Cs. melanura throughout its geographic range suggest that this mosquito may also be involved in epizootic / epidemic transmission to equines and humans in certain locales. Variations in blood feeding behavior may be a function of host availability, environmental factors, and/or underlying genetic differences among regional populations. Despite the importance of Cs. melanura in transmission and maintenance of EEE virus, the genetics of this species remains largely unexplored. METHODOLOGY AND PRINCIPLE FINDINGS To investigate the occurrence of genetic variation in Cs. melanura, the genome of this mosquito vector was sequenced resulting in a draft genome assembly of 1.28 gigabases with a contig N50 of 93.36 kilobases. Populations of Cs. melanura from 10 EEE virus foci in the eastern North America were genotyped with double-digest RAD-seq. Following alignment of reads to the reference genome, variant calling, and filtering, 40,384 SNPs were retained for downstream analyses. Subsequent analyses revealed genetic differentiation between northern and southern populations of this mosquito species. Moreover, limited fine-scale population structure was detected throughout northeastern North America, suggesting local differentiation of populations but also a history of ancestral polymorphism or contemporary gene flow. Additionally, a genetically distinct cluster was identified predominantly at two northern sites. CONCLUSION AND SIGNIFICANCE This study elucidates the first evidence of fine-scale population structure in Cs. melanura throughout its eastern range and detects evidence of gene flow between populations in northeastern North America. This investigation provides the groundwork for examining the consequences of genetic variations in the populations of this mosquito species that could influence vector-host interactions and the risk of human and equine infection with EEE virus.
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Affiliation(s)
- John Soghigian
- Department of Environmental Sciences, Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
| | - Theodore G. Andreadis
- Department of Environmental Sciences, Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Goudarz Molaei
- Department of Environmental Sciences, Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
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15
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Oliver J, Lukacik G, Kokas J, Campbell SR, Kramer LD, Sherwood JA, Howard JJ. Twenty years of surveillance for Eastern equine encephalitis virus in mosquitoes in New York State from 1993 to 2012. Parasit Vectors 2018; 11:362. [PMID: 29941031 PMCID: PMC6019270 DOI: 10.1186/s13071-018-2950-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 06/13/2018] [Indexed: 11/10/2022] Open
Abstract
Background The year 1971 was the first time in New York State (NYS) that Eastern equine encephalitis virus (EEEV) was identified in mosquitoes, in Culiseta melanura and Culiseta morsitans. At that time, state and county health departments began surveillance for EEEV in mosquitoes. Methods From 1993 to 2012, county health departments continued voluntary participation with the state health department in mosquito and arbovirus surveillance. Adult female mosquitoes were trapped, identified, and pooled. Mosquito pools were tested for EEEV by Vero cell culture each of the twenty years. Beginning in 2000, mosquito extracts and cell culture supernatant were tested by reverse transcriptase-polymerase chain reaction (RT-PCR). Results During the years 1993 to 2012, EEEV was identified in: Culiseta melanura, Culiseta morsitans, Coquillettidia perturbans, Aedes canadensis (Ochlerotatus canadensis), Aedes vexans, Anopheles punctipennis, Anopheles quadrimaculatus, Psorophora ferox, Culex salinarius, and Culex pipiens-restuans group. EEEV was detected in 427 adult mosquito pools of 107,156 pools tested totaling 3.96 million mosquitoes. Detections of EEEV occurred in three geographical regions of NYS: Sullivan County, Suffolk County, and the contiguous counties of Madison, Oneida, Onondaga and Oswego. Detections of EEEV in mosquitoes occurred every year from 2003 to 2012, inclusive. EEEV was not detected in 1995, and 1998 to 2002, inclusive. Conclusions This was the first time in NYS that EEEV was detected in Cx. salinarius, Ps. ferox and An. punctipennis. The detection of EEEV in mosquitoes every year for 10 years was the longest time span since surveillance began in 1971. The calendar date of the earliest annual appearance of EEEV in mosquitoes did not change during surveillance spanning 42 years.
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Affiliation(s)
- JoAnne Oliver
- Department of Health, Central New York Regional Office, State of New York, 217 South Salina Street, Syracuse, NY, 13202, USA. .,School of Agriculture and Natural Resources, Morrisville State College, State University of New York, 80 Eaton Street, Morrisville, NY, 13408, USA.
| | - Gary Lukacik
- Division of Epidemiology, Department of Health, Vector Surveillance Unit, Bureau of Communicable Diseases, State of New York, Room 651, Corning Tower, Empire State Plaza, Albany, NY, 12237, USA
| | - John Kokas
- Vector Surveillance Unit, Louis Calder Center, Fordham University, 53 Whippoorwill Road, Armonk, NY, 10504, USA
| | - Scott R Campbell
- Arthropod-Borne Disease Laboratory, Suffolk County Department of Health Services, 360 Yaphank Avenue, Suite 2A, Yaphank, NY, 11980, USA
| | - Laura D Kramer
- Arbovirus Laboratory, Division of Infectious Diseases, Wadsworth Center, Department of Health, State of New York, 5668 State Farm Road, Slingerlands, NY, 12159, USA.,School of Public Health, University at Albany, State University of New York, One University Place, Rensselaer, NY, 12144, USA
| | - James A Sherwood
- Department of Health, Central New York Regional Office, State of New York, 217 South Salina Street, Syracuse, NY, 13202, USA
| | - John J Howard
- Department of Health, Central New York Regional Office, State of New York, 217 South Salina Street, Syracuse, NY, 13202, USA
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Kumar R, Patil RD. Cryptic etiopathological conditions of equine nervous system with special emphasis on viral diseases. Vet World 2017; 10:1427-1438. [PMID: 29391683 PMCID: PMC5771167 DOI: 10.14202/vetworld.2017.1427-1438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 10/30/2017] [Indexed: 01/04/2023] Open
Abstract
The importance of horse (Equus caballus) to equine practitioners and researchers cannot be ignored. An unevenly distributed population of equids harbors numerous diseases, which can affect horses of any age and breed. Among these, the affections of nervous system are potent reason for death and euthanasia in equids. Many episodes associated with the emergence of equine encephalitic conditions have also pose a threat to human population as well, which signifies their pathogenic zoonotic potential. Intensification of most of the arboviruses is associated with sophisticated interaction between vectors and hosts, which supports their transmission. The alphaviruses, bunyaviruses, and flaviviruses are the major implicated groups of viruses involved with equines/humans epizootic/epidemic. In recent years, many outbreaks of deadly zoonotic diseases such as Nipah virus, Hendra virus, and Japanese encephalitis in many parts of the globe addresses their alarming significance. The equine encephalitic viruses differ in their global distribution, transmission and main vector species involved, as discussed in this article. The current review summarizes the status, pathogenesis, pathology, and impact of equine neuro-invasive conditions of viral origin. A greater understanding of these aspects might be able to provide development of advances in neuro-protective strategies in equine population.
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Affiliation(s)
- Rakesh Kumar
- Department of Veterinary Pathology, Dr. G.C. Negi College of Veterinary and Animal Sciences, CSK Himachal Pradesh Agricultural University, Palampur - 176 062, Himachal Pradesh, India
| | - Rajendra D Patil
- Department of Veterinary Pathology, Dr. G.C. Negi College of Veterinary and Animal Sciences, CSK Himachal Pradesh Agricultural University, Palampur - 176 062, Himachal Pradesh, India
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17
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Abstract
Pokémon Go is a new game that encourages players to venture outdoors and interact with others in the pursuit of virtual Pokémon characters. With more time spent outdoors overall and in sometimes large congregations, Pokémon Go players could inadvertently elevate their risk of exposure to mosquito-borne diseases when playing in certain areas at certain times of year. Here, we make an initial assessment of the possible scope of this concern in the continental United States, which experiences its highest seasonal transmission of West Nile, Zika, and other viruses during summer and early fall. In particular, we propose that the times of day when many disease-relevant mosquito species are most likely to engage in blood feeding coincide with times of day when Pokémon Go activity is likely to be high, and we note that locations serving as hubs of Pokémon Go activity may in some cases overlap with areas where these mosquitoes are actively engaged in blood feeding. Although the risk of mosquito-borne diseases in the continental U.S. is low overall and is unlikely to be impacted significantly by Pokémon Go, it is nonetheless important for Pokémon Go players and others who spend time outdoors engaging in activities such as barbecues and gardening to be aware of these ongoing risks and to take appropriate preventative measures in light of the potential for outdoor activity to modify individual-level risk of exposure. As Pokémon Go and other augmented reality games become available in other parts of the world, similar risks should be assessed in a manner that is consistent with the local epidemiology of mosquito-borne diseases in those areas.
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18
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Hesson JC, Lundström JO, Tok A, Östman Ö, Lundkvist Å. Temporal Variation in Sindbis Virus Antibody Prevalence in Bird Hosts in an Endemic Area in Sweden. PLoS One 2016; 11:e0162005. [PMID: 27579607 PMCID: PMC5007008 DOI: 10.1371/journal.pone.0162005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/16/2016] [Indexed: 11/25/2022] Open
Abstract
Sindbis virus (SINV) is a mosquito-borne bird virus that occasionally causes human disease in Fennoscandia, suggested to have cyclic 7-year intervals between outbreaks. Reliable data on human infections in Sweden is however lacking. Here we investigated the SINV antibody prevalence among birds in a Swedish area endemic to SINV to scrutinize if a cyclic variation in antibody prevalence is present in the natural host of SINV. Serum from birds were sampled in the summers of 2002–2004 and 2009 in the floodplains of the River Dalälven in central Sweden, with 2002 and 2009 representing hypothesized years of SINV outbreaks. A total of 963 birds from 52 species (mainly passerines) were tested for the presence of SINV antibodies using a plaque reduction neutralization test. The highest SINV antibody prevalence was found in Turdidae species, specifically Fieldfare, Redwing and Song thrush in which more than 70% of sampled individuals had antibodies to SINV in 2009. The SINV antibody prevalence significantly varied between years with 2% in 2002, 8% in 2003, 14% in 2004 and 37% in 2009. Antibodies were found equally often in hatchlings and in adults and increased from early to late in the season. Clearly, the SINV antibody prevalence was not elevated in the bird hosts in the predicted outbreak year 2002, thus solid evidence of a cyclic occurrence of SINV in Sweden is still lacking.
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Affiliation(s)
- Jenny Christina Hesson
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, Uppsala, Sweden.,Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Jan O Lundström
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, Uppsala, Sweden.,Swedish Biological Mosquito Control Project, Nedre Dalälvens Utvecklings AB, Gysinge, Sweden
| | - Atalay Tok
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, Uppsala, Sweden
| | - Örjan Östman
- Department of Aquatic Resources, Institute of Coastal Research, Swedish University of Agricultural Sciences, Öregrund, Sweden
| | - Åke Lundkvist
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, Uppsala, Sweden.,Laboratory of Clinical Microbiology, Uppsala University Hospital, Uppsala, Sweden
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19
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Shepard JJ, Andreadis TG, Thomas MC, Molaei G. Host associations of mosquitoes at eastern equine encephalitis virus foci in Connecticut, USA. Parasit Vectors 2016; 9:474. [PMID: 27577939 PMCID: PMC5006286 DOI: 10.1186/s13071-016-1765-1] [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: 04/21/2016] [Accepted: 08/19/2016] [Indexed: 01/19/2023] Open
Abstract
Background Eastern equine encephalitis virus (EEEV) is a highly pathogenic mosquito-borne arbovirus, with active transmission foci in freshwater hardwood swamps in eastern North America, where enzootic transmission is maintained between the ornithophilic mosquito, Culiseta melanura, and wild passerine birds. The role of other locally abundant mosquito species in virus transmission and their associations with vertebrate hosts as sources of blood meals within these foci are largely unknown but are of importance in clarifying the dynamics of enzootic and epidemic/epizootic transmission. Methods Blood-engorged mosquitoes were collected from resting boxes at four established EEEV foci in Connecticut during 2010–2011. Mosquitoes were identified to species, and the identity of vertebrate hosts was determined based on mitochondrial cytochrome b and/or cytochrome c oxidase subunit I gene sequences of polymerase chain reaction products. Results The vertebrate hosts of 378 (50.3 % of engorged mosquitoes) specimens, representing 12 mosquito species, were identified. Culiseta morsitans (n = 54; 67.5 %), Culex restuans (n = 4; 66.7 %), and Cx. pipiens (n = 2; 100 %) acquired blood meals exclusively from avian hosts, whereas Aedes cinereus (n = 6; 66.7 %), Ae. canadensis (n = 2; 100 %), and Ae. stimulans (n = 1; 100 %) obtained blood meals solely from mammals. Species that fed opportunistically on both avian and mammalian hosts included: Ae. thibaulti (n = 21 avian, and n = 181 mammalian; 57.2 %), Anopheles punctipennis (n = 8 and n = 40; 44.0 %), An. quadrimaculatus (n = 1 and n = 23; 35.7 %), Coquillettidia perturbans (n = 3 and n = 3; 46.2 %) and Ae. abserratus (n = 1 and n = 2; 23.1 %). Culex territans obtained blood meals from avian and amphibian hosts (n = 18 and n = 5; 26.6 %). Mixed blood meals originating from both avian and mammalian hosts were identified in An. quadrimaculatus (n = 1), and Cx. territans (n = 2). Conclusions Our findings indicate that wood thrush, tufted titmouse, and a few other avian species serve as hosts for mosquitoes, and likely contribute to amplification of EEEV. Our study supports the role of Cs. morsitans in enzootic transmission of EEEV among avian species. Culex territans will seek blood from multiple vertebrate classes, suggesting that this species may contribute to epizootic transmission of the virus. Our findings support roles for Cq. perturbans and An. quadrimaculatus as epidemic/epizootic vectors to humans, horses, and white-tailed deer. Despite its abundance, the potential of Ae. thibaulti to serve as a “bridge vector” for EEEV remains unclear in the absence of any definitive knowledge on its competency for the virus. The contribution of white-tailed deer to the dynamics of EEEV transmission is not fully understood, but findings indicate repeated exposure due to frequent feeding by vector competent mosquito species.
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Affiliation(s)
- John J Shepard
- Department of Environmental Sciences, and Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA
| | - Theodore G Andreadis
- Department of Environmental Sciences, and Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA.,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, P.O. Box 208034, New Haven, CT, 06520-8034, USA
| | - Michael C Thomas
- Department of Environmental Sciences, and Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA
| | - Goudarz Molaei
- Department of Environmental Sciences, and Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA. .,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, P.O. Box 208034, New Haven, CT, 06520-8034, USA.
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20
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Pedersen K, Marks DR, Wang E, Eastwood G, Weaver SC, Goldstein SM, Sinnett DR, DeLiberto TJ. Widespread Detection of Antibodies to Eastern Equine Encephalitis, West Nile, St. Louis Encephalitis, and Turlock Viruses in Various Species of Wild Birds from Across the United States. Am J Trop Med Hyg 2016; 95:206-11. [PMID: 27162269 DOI: 10.4269/ajtmh.15-0840] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 03/22/2016] [Indexed: 12/22/2022] Open
Abstract
Wild birds serve as amplifying hosts for many arboviruses, and are thought to be responsible for introducing these viruses into new areas during migration as well as reintroducing them to places where winter temperatures disrupt mosquito-borne transmission. To learn more about four mosquito-borne arboviruses of concern to human or animal health, we tested sera from 997 wild birds of 54 species and 17 families across 44 states of the United States collected from January 1, 2013, through September 30, 2013. Samples were tested for antibody against eastern equine encephalitis, St. Louis encephalitis, West Nile, and Turlock viruses using plaque reduction neutralization tests with an endpoint of 80% or greater. Of the 333 (33.4%) birds that tested positive for antibody to at least one arbovirus, 29.7% were exposed to two or more arboviruses. Exposure to all four arboviruses was detected in Canada geese, double-crested cormorants, mallards, mute swans, laughing gulls, and American coots. Our results suggest that exposure to arboviruses is widespread in the United States across a diversity of wild bird species.
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Affiliation(s)
- Kerri Pedersen
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Fort Collins, Colorado.
| | - David R Marks
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Okemos, Michigan
| | - Eryu Wang
- Department of Microbiology and Immunology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas
| | - Gillian Eastwood
- Department of Microbiology and Immunology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas
| | - Scott C Weaver
- Department of Microbiology and Immunology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas
| | - Samuel M Goldstein
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Honolulu, Hawaii
| | - David R Sinnett
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Palmer, Alaska
| | - Thomas J DeLiberto
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado
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Molaei G, Thomas MC, Muller T, Medlock J, Shepard JJ, Armstrong PM, Andreadis TG. Dynamics of Vector-Host Interactions in Avian Communities in Four Eastern Equine Encephalitis Virus Foci in the Northeastern U.S. PLoS Negl Trop Dis 2016; 10:e0004347. [PMID: 26751704 PMCID: PMC4713425 DOI: 10.1371/journal.pntd.0004347] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 12/09/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Eastern equine encephalitis (EEE) virus (Togaviridae, Alphavirus) is a highly pathogenic mosquito-borne zoonosis that is responsible for occasional outbreaks of severe disease in humans and equines, resulting in high mortality and neurological impairment in most survivors. In the past, human disease outbreaks in the northeastern U.S. have occurred intermittently with no apparent pattern; however, during the last decade we have witnessed recurring annual emergence where EEE virus activity had been historically rare, and expansion into northern New England where the virus had been previously unknown. In the northeastern U.S., EEE virus is maintained in an enzootic cycle involving the ornithophagic mosquito, Culiseta melanura, and wild passerine (perching) birds in freshwater hardwood swamps. However, the identity of key avian species that serve as principal virus reservoir and amplification hosts has not been established. The efficiency with which pathogen transmission occurs within an avian community is largely determined by the relative reservoir competence of each species and by ecological factors that influence contact rates between these avian hosts and mosquito vectors. METHODOLOGY AND PRINCIPLE FINDINGS Contacts between vector mosquitoes and potential avian hosts may be directly quantified by analyzing the blood meal contents of field-collected specimens. We used PCR-based molecular methods and direct sequencing of the mitochondrial cytochrome b gene for profiling of blood meals in Cs. melanura, in an effort to quantify its feeding behavior on specific vertebrate hosts, and to infer epidemiologic implications in four historic EEE virus foci in the northeastern U.S. Avian point count surveys were conducted to determine spatiotemporal host community composition. Of 1,127 blood meals successfully identified to species level, >99% of blood meals were from 65 avian hosts in 27 families and 11 orders, and only seven were from mammalian hosts representing three species. We developed an empirically informed mathematical model for EEE virus transmission using Cs. melanura abundance and preferred and non-preferred avian hosts. To our knowledge this is the first mathematical model for EEE virus, a pathogen with many potential hosts, in the northeastern U.S. We measured strong feeding preferences for a number of avian species based on the proportion of mosquito blood meals identified from these bird species in relation to their observed frequencies. These included: American Robin, Tufted Titmouse, Common Grackle, Wood Thrush, Chipping Sparrow, Black-capped Chickadee, Northern Cardinal, and Warbling Vireo. We found that these bird species, most notably Wood Thrush, play a dominant role in supporting EEE virus amplification. It is also noteworthy that the competence of some of the aforementioned avian species for EEE virus has not been established. Our findings indicate that heterogeneity induced by mosquito host preference, is a key mediator of the epizootic transmission of vector-borne pathogens. CONCLUSION AND SIGNIFICANCE Detailed knowledge of the vector-host interactions of mosquito populations in nature is essential for evaluating their vectorial capacity and for assessing the role of individual vertebrates as reservoir hosts involved in the maintenance and amplification of zoonotic agents of human diseases. Our study clarifies the host associations of Cs. melanura in four EEE virus foci in the northeastern U.S., identifies vector host preferences as the most important transmission parameter, and quantifies the contribution of preference-induced contact heterogeneity to enzootic transmission. Our study identifies Wood Thrush, American Robin and a few avian species that may serve as superspreaders of EEE virus. Our study elucidates spatiotemporal host species utilization by Cs. melanura in relation to avian host community. This research provides a basis to better understand the involvement of Cs. melanura and avian hosts in the transmission and ecology of EEE virus and the risk of human infection in virus foci.
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Affiliation(s)
- Goudarz Molaei
- Center for Vector Biology and Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
| | - Michael C. Thomas
- Center for Vector Biology and Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
| | - Tim Muller
- Department of Mathematics, College of Science, Oregon State University, Corvallis, Oregon, United States of America
| | - Jan Medlock
- Department of Biomedical sciences, College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, United States of America
| | - John J. Shepard
- Center for Vector Biology and Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
| | - Philip M. Armstrong
- Center for Vector Biology and Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
| | - Theodore G. Andreadis
- Center for Vector Biology and Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
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22
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Molaei G, Armstrong PM, Graham AC, Kramer LD, Andreadis TG. Insights into the recent emergence and expansion of eastern equine encephalitis virus in a new focus in the Northern New England USA. Parasit Vectors 2015; 8:516. [PMID: 26453283 PMCID: PMC4600208 DOI: 10.1186/s13071-015-1145-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/03/2015] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Eastern equine encephalomyelitis virus (EEEV) causes a highly pathogenic zoonosis that circulates in an enzootic cycle involving the ornithophagic mosquito, Culiseta melanura, and wild passerine birds in freshwater hardwood swamps in the northeastern U.S. Epidemic/epizootic transmission to humans/equines typically occurs towards the end of the transmission season and is generally assumed to be mediated by locally abundant and contiguous mammalophagic "bridge vector" mosquitoes. METHODS Engorged mosquitoes were collected using CDC light, resting box, and gravid traps during epidemic transmission of EEEV in 2012 in Addison and Rutland counties, Vermont. Mosquitoes were identified to species and blood meal analysis performed by sequencing mitochondrial cytochrome b gene polymerase chain reaction products. Infection status with EEEV in mosquitoes was determined using cell culture and RT-PCR assays, and all viral isolates were sequenced and compared to other EEEV strains by phylogenetic analysis. RESULTS The host choices of 574 engorged mosquitoes were as follows: Cs. melanura (n = 331, 94.3 % avian-derived, 5.7 % mammalian-derived); Anopheles quadrimaculatus (n = 164, 3.0 % avian, 97.0 % mammalian); An. punctipennis (n = 56, 7.2 % avian, 92.8 % mammalian), Aedes vexans (n = 9, 22.2 % avian, 77.8 % mammalian); Culex pipiens s.l. n = 6, 100 % avian); Coquillettidia perturbans (n = 4, 25.0 % avian, 75.0 % mammalian); and Cs. morsitans (n = 4, 100 % avian). A seasonal shift in blood feeding by Cs. melanura from Green Heron towards other avian species was observed. EEEV was successfully isolated from blood-fed Cs. melanura and analyzed by phylogenetic analysis. Vermont strains from 2012 clustered with viral strains previously isolated in Virginia yet were genetically distinct from an earlier EEEV isolate from Vermont during 2011. CONCLUSIONS Culiseta melanura acquired blood meals primarily from birds and focused feeding activity on several competent species capable of supporting EEEV transmission. Culiseta melanura also occasionally obtained blood meals from mammalian hosts including humans. This mosquito species serves as the primary vector of EEEV among wild bird species, but also is capable of occasionally contributing to epidemic/epizootic transmission of EEEV to humans/equines. Other mosquito species including Cq. perturbans that feed more opportunistically on both avian and mammalian hosts may be important in epidemic/epizootic transmission under certain conditions. Phylogenetic analyses suggest that EEEV was independently introduced into Vermont on at least two separate occasions.
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Affiliation(s)
- Goudarz Molaei
- Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA.
| | - Philip M Armstrong
- Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA.
| | - Alan C Graham
- Vermont Agency of Agriculture, 322 Industrial Lane, Barre, VT, 05641, USA.
| | - Laura D Kramer
- Wadsworth Center, New York State Department of Health, 5668 State Farm Rd, Slingerlands, NY, 12159, USA.
| | - Theodore G Andreadis
- Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT, 06511, USA.
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Downs JA, Hyzer G, Marion E, Smith ZJ, Kelen PV, Unnasch TR. Mapping eastern equine encephalitis virus risk for white-tailed deer in Michigan. APPLIED GEOGRAPHY (SEVENOAKS, ENGLAND) 2015; 64:66-73. [PMID: 26494931 PMCID: PMC4610038 DOI: 10.1016/j.apgeog.2015.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Eastern equine encephalitis (EEE) is a mosquito-borne viral disease that is often fatal to humans and horses. Some species including white-tailed deer and passerine birds can survive infection with the EEE virus (EEEV) and develop antibodies that can be detected using laboratory techniques. In this way, collected serum samples from free ranging white-tailed deer can be used to monitor the presence of the virus in ecosystems. This study developed and tested a risk index model designed to predict EEEV activity in white-tailed deer in a three-county area of Michigan. The model evaluates EEEV risk on a continuous scale from 0.0 (no measurable risk) to 1.0 (highest possible risk). High risk habitats are identified as those preferred by white-tailed deer that are also located in close proximity to an abundance of wetlands and lowland forests, which support disease vectors and hosts. The model was developed based on relevant literature and was tested with known locations of infected deer that showed neurological symptoms. The risk index model accurately predicted the known locations, with the mean value for those sites equal to the 94th percentile of values in the study area. The risk map produced by the model could be used refine future EEEV monitoring efforts that use serum samples from free-ranging white-tailed deer to monitor viral activity. Alternatively, it could be used focus educational efforts targeted toward deer hunters that may have elevated risks of infection.
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Affiliation(s)
- Joni A Downs
- School of Geosciences, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | - Garrett Hyzer
- School of Geosciences, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | - Eric Marion
- School of Geosciences, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | - Zachary J Smith
- School of Geosciences, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | | | - Thomas R Unnasch
- College of Public Health, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
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Molaei G, Armstrong PM, Abadam CF, Akaratovic KI, Kiser JP, Andreadis TG. Vector-Host Interactions of Culiseta melanura in a Focus of Eastern Equine Encephalitis Virus Activity in Southeastern Virginia. PLoS One 2015; 10:e0136743. [PMID: 26327226 PMCID: PMC4556703 DOI: 10.1371/journal.pone.0136743] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 08/07/2015] [Indexed: 02/08/2023] Open
Abstract
Eastern equine encephalitis virus (EEEV) causes a highly pathogenic mosquito-borne zoonosis that is responsible for sporadic outbreaks of severe illness in humans and equines in the eastern USA. Culiseta (Cs.) melanura is the primary vector of EEEV in most geographic regions but its feeding patterns on specific avian and mammalian hosts are largely unknown in the mid-Atlantic region. The objectives of our study were to: 1) identify avian hosts of Cs. melanura and evaluate their potential role in enzootic amplification of EEEV, 2) assess spatial and temporal patterns of virus activity during a season of intense virus transmission, and 3) investigate the potential role of Cs. melanura in epidemic/epizootic transmission of EEEV to humans and equines. Accordingly, we collected mosquitoes at 55 sites in Suffolk, Virginia in 2013, and identified the source of blood meals in engorged mosquitoes by nucleotide sequencing PCR products of the mitochondrial cytochrome b gene. We also examined field-collected mosquitoes for evidence of infection with EEEV using Vector Test, cell culture, and PCR. Analysis of 188 engorged Cs. melanura sampled from April through October 2013 indicated that 95.2%, 4.3%, and 0.5% obtained blood meals from avian, mammalian, and reptilian hosts, respectively. American Robin was the most frequently identified host for Cs. melanura (42.6% of blood meals) followed by Northern Cardinal (16.0%), European Starling (11.2%), Carolina Wren (4.3%), and Common Grackle (4.3%). EEEV was detected in 106 mosquito pools of Cs. melanura, and the number of virus positive pools peaked in late July with 22 positive pools and a Maximum Likelihood Estimation (MLE) infection rate of 4.46 per 1,000 mosquitoes. Our findings highlight the importance of Cs. melanura as a regional EEEV vector based on frequent feeding on virus-competent bird species. A small proportion of blood meals acquired from mammalian hosts suggests the possibility that this species may occasionally contribute to epidemic/epizootic transmission of EEEV.
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Affiliation(s)
- Goudarz Molaei
- Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
| | - Philip M. Armstrong
- Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
| | - Charles F. Abadam
- Suffolk Mosquito Control, Department of Public Works, Suffolk, Virginia, United States of America
| | - Karen I. Akaratovic
- Suffolk Mosquito Control, Department of Public Works, Suffolk, Virginia, United States of America
| | - Jay P. Kiser
- Suffolk Mosquito Control, Department of Public Works, Suffolk, Virginia, United States of America
| | - Theodore G. Andreadis
- Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, United States of America
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25
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Burkett-Cadena ND, Bingham AM, Hunt B, Morse G, Unnasch TR. Ecology of Culiseta Melanura and Other Mosquitoes (Diptera: Culicidae) from Walton County, FL, During Winter Period 2013-2014. JOURNAL OF MEDICAL ENTOMOLOGY 2015; 52:1074-82. [PMID: 26336227 PMCID: PMC4668758 DOI: 10.1093/jme/tjv087] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 06/02/2015] [Indexed: 06/05/2023]
Abstract
Winter ecology of putative vectors of eastern equine encephalomyelitis virus (EEEV) in northern Florida was investigated at field locations with evidence of historic EEEV winter transmission. Light traps and resting shelters were used to sample the mosquito community in the vicinity of eight sentinel flocks throughout the winter period (November-April) of 2013 and 2014 in Walton County, FL. Overall mosquito activity was relatively low, although mosquitoes were captured during each week of the study period. Mosquito activity was linked to morning temperature, and females were captured when ambient morning temperatures were quite low (1-5°C). Anopheles crucians Wiedemann, Culex erraticus (Dyar and Knab), Culex territans Walker, and Culiseta melanura (Coquillett) were the most commonly collected mosquito species (of 20 total species). Analysis of blood-engorged mosquitoes revealed a number of mosquito species feeding upon chickens, other birds, amphibians, and domestic and wild mammals. Cs. melanura fed primarily upon chickens and songbirds (Passeriformes), suggesting that this mosquito species is the likely winter vector of EEEV to sentinel chickens in northern Florida. Both resident and nonresident songbird species were fed upon, constituting 63.9 and 36.1% of total songbird meals, respectively. Our results suggest important roles for Cs. melanura and songbird hosts for the winter transmission of EEEV in northern Florida.
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Affiliation(s)
| | - Andrea M Bingham
- Department of Global Health, University of South Florida, Tampa, FL 33612
| | - Brenda Hunt
- North Walton Mosquito Control District, 129 Montgomery Circle, DeFuniak Springs, FL 32435
| | - Gary Morse
- North Walton Mosquito Control District, 129 Montgomery Circle, DeFuniak Springs, FL 32435
| | - Thomas R Unnasch
- Department of Global Health, University of South Florida, Tampa, FL 33612
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Abstract
Mosquito-borne diseases affect horses worldwide. Mosquito-borne diseases generally cause encephalomyelitis in the horse and can be difficult to diagnose antemortem. In addition to general disease, and diagnostic and treatment aspects, this review article summarizes the latest information on these diseases, covering approximately the past 5 years, with a focus on new equine disease encroachments, diagnostic and vaccination aspects, and possible therapeutics on the horizon.
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