Phylogenetic Analysis of Eastern Equine Encephalitis Virus Isolates from Florida

White, Gregory S.; Pickett, Brett E.; Lefkowitz, Elliot J.; Johnson, Amelia G.; Ottendorfer, Christy L.; Stark, Lillian M.; Unnasch, Thomas R.

doi:10.4269/ajtmh.2011.10-0267

Cited by 16 publications

(9 citation statements)

References 28 publications

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“…The genetic analyses reveal that EEEV is a generally well-conserved virus with over 99% nucleotide/amino acid similarity across the genome and only two diverse amino acid positions detected by entropy analysis. The most variability is in the nsP3 gene, supporting previous studies based on partial genomes (6,8,28). In addition, EEEV exhibited strong, clock-like evolution with a mean evolutionary rate of 1.81 ϫ 10 Ϫ4 subs/site/year.…”

Section: Discussionsupporting

confidence: 85%

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

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Heberlein-Larson

et al. 2018

J Virol

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Eastern 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 U.S. To test this hypothesis, we sequenced complete genomes of 433 EEEV strains collected within the U.S. 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 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 U.S., and provided general insights into the evolution and transmission of other avian mosquito-borne viruses in this region. Eastern equine encephalitis virus (EEEV) infections are severe in horses and humans on the east coast of the United States with over 90% mortality rate in horses, approximately 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 U.S., 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.

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Section: Discussionsupporting

confidence: 85%

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

Tan

Lam

Heberlein-Larson

et al. 2018

J Virol

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“…For example, EEEV circulates year-round in Florida, while it is dormant during the winter months elsewhere (Wellings et al 1972, Day and Stark 1996b). EEEV isolates from Florida appear to be genetically similar to those found in the northeastern United States (Weaver et al 1991, 1994; Armstrong et al 2008; Young et al 2008; White et al 2011). However, specific ecological niches may exist that enhance amplification and transmission of EEEV in Florida, making the state heterogeneous with respect to EEEV activity.…”

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confidence: 69%

Habitat Associations of Eastern Equine Encephalitis Transmission in Walton County Florida

et al. 2012

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Eastern Equine Encephalitis virus (EEEV; family Togaviridae, genus Alphavirus) a highly pathogenic mosquito-borne virus is endemic to eastern North America. The ecology of EEEV in Florida differs from that in other parts of the United States; EEEV in the northeastern United States is historically associated with freshwater wetlands. No formal test of habitat associations of EEEV in Florida has been reported. Geographical Information Sciences (GIS) was used in conjunction with sentinel chicken EEEV seroconversion rate data as a means to examine landscape features associated with EEEV transmission in Walton County, FL. Sentinel sites were categorized as enzootic, periodically enzootic, and negative based on the number of chicken seroconversions to EEEV from 2005 to 2009. EEEV transmission was then categorized by land cover usage using Arc GIS 9.3. The land classification data were analyzed using the Kruskal–Wallis test for each land use class to determine which habitats may be associated with virus transmission as measured by sentinel chicken seroconversion rates. The habitat class found to be most significantly associated with EEEV transmission was tree plantations. The ecological factor most commonly associated with reduced levels of EEEV transmission was vegetated nonforest wetlands. Culiseta melanura (Coquillett), the species generally considered to be the major enzootic EEEV vector, was relatively evenly distributed across all habitat classes, while Aedes vexans (Meigen) and Anopheles crucians Weidemann were most commonly associated with tree plantation habitats.

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“…The grouping is similar to that designated in a previous small-scale (six WGSs and 15 partial sequences) phylogenetic study of Florida EEEV. 26 In addition, we tested whether viral phylogenetic clustering is influenced by viral source (host) or sampling dates, we grouped viruses into four host sources (mosquito, avian, equine, and other mammals) and four sampling periods (before 2000, [2000][2001][2002][2003][2004][2005][2006][2007][2008][2009], and 2010-2014) separately. We determined the overall statistical significance of association between the EEEV phylogenies and the viral traits described above (i.e., geography, host, and sampling date) using two phylogeny-trait association statistical tests: the parsimony score (PS) and the association index (AI).…”

Section: Methodsmentioning

confidence: 99%

Complex Epidemiological Dynamics of Eastern Equine Encephalitis Virus in Florida

Heberlein-Larson

Tan

Stark

et al. 2019

The American Journal of Tropical Medicine and Hygiene

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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 yearround 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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Phylogenetic Analysis of Eastern Equine Encephalitis Virus Isolates from Florida

Cited by 16 publications

References 28 publications

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

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

Habitat Associations of Eastern Equine Encephalitis Transmission in Walton County Florida

Complex Epidemiological Dynamics of Eastern Equine Encephalitis Virus in Florida

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