scholarly journals Ecology and Epidemiology of Eastern Equine Encephalitis Virus in the Northeastern United States: An Historical Perspective

2021 ◽  
Author(s):  
Philip M Armstrong ◽  
Theodore G Andreadis
Keyword(s):  
United States ◽  
Mosquito Species ◽  
Virus Transmission ◽  
Bird Species ◽  
Disease Outbreaks ◽  
Encephalitis Virus ◽  
Eastern Equine Encephalitis Virus ◽  
Northeastern United States ◽  
Eastern Equine Encephalitis ◽  
Equine Encephalitis Virus

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.

scholarly journals Ecology of Eastern Equine Encephalitis Virus in the Southeastern United States: Incriminating Vector and Host Species Responsible for Virus Amplification, Persistence, and Dispersal

2021 ◽  
Author(s):  
Nathan D Burkett-Cadena ◽  
Jonathan F Day ◽  
Thomas R Unnasch
Keyword(s):  
North America ◽  
Phylogenetic Analyses ◽  
Mosquito Species ◽  
Severe Disease ◽  
Bird Species ◽  
Encephalitis Virus ◽  
Eastern North America ◽  
Eastern Equine Encephalitis Virus ◽  
Eastern Equine Encephalitis ◽  
Equine Encephalitis Virus

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.

scholarly journals Facts About Wildlife Diseases: Eastern Equine Encephalitis

EDIS ◽  
2019 ◽  
Vol 2019 (2) ◽  
Author(s):  
Samantha M Wisely ◽  
Karen Hood
Keyword(s):  
United States ◽  
Encephalitis Virus ◽  
Eastern United States ◽  
Mosquito Vectors ◽  
Eastern Equine Encephalitis Virus ◽  
Wildlife Diseases ◽  
Eastern Equine Encephalitis ◽  
Wildlife Ecology ◽  
Fact Sheet ◽  
Equine Encephalitis Virus

The Eastern equine encephalitis virus (EEEV) causes Eastern equine encephalitis (EEE) disease in birds, humans, horses, and other animals in the eastern United States, including Florida, which is especially receptive to the virus because of its freshwater hardwood swamps and wetlands, which provide good niches for the mosquito vectors of the disease. This 5-page fact sheet written by Samantha Wisely and Karen Hood and published by the UF/IFAS Department of Wildlife Ecology and Conservation describes the disease and includes strategies for limiting its spread. http://edis.ifas.ufl.edu/uw453

scholarly journals Large-Scale Complete-Genome Sequencing and Phylodynamic Analysis of Eastern Equine Encephalitis Virus Reveals Source-Sink Transmission Dynamics in the United States

2018 ◽  
Vol 92 (12) ◽  
Author(s):  
Yi Tan ◽  
Tommy Tsan-Yuk Lam ◽  
Lea A. Heberlein-Larson ◽  
Sandra C. Smole ◽  
Albert J. Auguste ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Mortality Rate ◽  
The United States ◽  
Encephalitis Virus ◽  
Eastern Equine Encephalitis Virus ◽  
Genome Sequences ◽  
Eastern Equine Encephalitis ◽  
Equine Encephalitis Virus ◽  
Source Sink

ABSTRACTEastern equine encephalitis virus (EEEV) has a high case-fatality rate in horses and humans, and Florida has been hypothesized to be the source of EEEV epidemics for the northeastern United States. To test this hypothesis, we sequenced complete genomes of 433 EEEV strains collected within the United States from 1934 to 2014. Phylogenetic analysis suggested EEEV evolves relatively slowly and that transmission is enzootic in Florida, characterized by higher genetic diversity and long-term local persistence. In contrast, EEEV strains in New York and Massachusetts were characterized by lower genetic diversity, multiple introductions, and shorter local persistence. Our phylogeographic analysis supported a source-sink model in which Florida is the major source of EEEV compared to the other localities sampled. In sum, this study revealed the complex epidemiological dynamics of EEEV in different geographic regions in the United States and provided general insights into the evolution and transmission of other avian mosquito-borne viruses in this region.IMPORTANCEEastern equine encephalitis virus (EEEV) infections are severe in horses and humans on the east coast of the United States with a >90% mortality rate in horses, an ∼33% mortality rate in humans, and significant brain damage in most human survivors. However, little is known about the evolutionary characteristics of EEEV due to the lack of genome sequences. By generating large collection of publicly available complete genome sequences, this study comprehensively determined the evolution of the virus, described the epidemiological dynamics of EEEV in different states in the United States, and identified Florida as one of the major sources. These results may have important implications for the control and prevention of other mosquito-borne viruses in the Americas.

scholarly journals Use of Cervid Serosurveys to Monitor Eastern Equine Encephalitis Virus Activity in Northern New England, United States, 2009–2017

2021 ◽  
Author(s):  
John-Paul Mutebi ◽  
Abigail A Mathewson ◽  
Susan P Elias ◽  
Sara Robinson ◽  
Alan C Graham ◽  
...  
Keyword(s):  
United States ◽  
New England ◽  
New Hampshire ◽  
Case Reports ◽  
Human Case ◽  
Encephalitis Virus ◽  
Eastern Equine Encephalitis Virus ◽  
Eastern Equine Encephalitis ◽  
Equine Encephalitis Virus ◽  
Northern New England

Abstract Vertebrate surveillance for eastern equine encephalitis virus (EEEV) activity usually focuses on three types of vertebrates: horses, passerine birds, and sentinel chicken flocks. However, there is a variety of wild vertebrates that are exposed to EEEV infections and can be used to track EEEV activity. In 2009, we initiated a pilot study in northern New England, United States, to evaluate the effectiveness of using wild cervids (free-ranging white-tailed deer and moose) as spatial sentinels for EEEV activity. In Maine, New Hampshire, and Vermont during 2009–2017, we collected blood samples from hunter-harvested cervids at tagging stations and obtained harvest location information from hunters. U.S. Centers for Disease Control and Prevention processed the samples for EEEV antibodies using plaque reduction neutralization tests (PRNTs). We detected EEEV antibodies in 6 to 17% of cervid samples in the different states and mapped cervid EEEV seropositivity in northern New England. EEEV antibody-positive cervids were the first detections of EEEV activity in the state of Vermont, in northern Maine, and northern New Hampshire. Our key result was the detection of the antibodies in areas far outside the extent of documented wild bird, mosquito, human case, or veterinary case reports of EEEV activity in Maine, New Hampshire, and Vermont. These findings showed that cervid (deer and moose) serosurveys can be used to characterize the geographic extent of EEEV activity, especially in areas with low EEEV activity or with little or no EEEV surveillance. Cervid EEEV serosurveys can be a useful tool for mapping EEEV activity in areas of North America in addition to northern New England.

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