Browsing by Author "Andreadis, Theodore G."

Now showing 1 - 4 of 4
  • Thumbnail Image
    Environmental Determinants of Aedes albopictus Abundance at a Northern Limit of Its Range in the United States
    Kache, Pallavi A.; Eastwood, Gillian; Collins-Palmer, Kaitlin; Katz, Marly; Falco, Richard C.; Bajwa, Waheed I.; Armstrong, Philip M.; Andreadis, Theodore G.; Diuk-Wasser, Maria A. (2020-02)
    Aedes albopictus is a vector of arboviruses with high rates of morbidity and mortality. The northern limit of Ae. albopictus in the northeastern United States runs through New York state (NYS) and Connecticut. We present a landscape-level analysis of mosquito abundance measured by daily counts of Ae. albopictus from 338 trap sites in 12 counties during May-September 2017. During the study period, the mean number of Ae. albopictus caught per day of trapping across all sites was 3.21. We constructed four sets of negative binomial generalized linear models to evaluate how trapping methodology, land cover, as well as temperature and precipitation at multiple time intervals influenced Ae. albopictus abundance. Biogents-Sentinel (BGS) traps were 2.78 times as efficient as gravid traps and 1.49 times as efficient as CO2-baited CDC light traps. Greater proportions of low- and medium-intensity development and low proportions of deciduous cover around the trap site were positively associated with increased abundance, as were minimum winter temperature and March precipitation. The cumulative precipitation within a 28-day time window before the date of collection had a nonlinear relationship with abundance, such that greater cumulative precipitation was associated with increased abundance until approximately 70 mm, above which there was a decrease in abundance. We concluded that populations are established in Nassau, Suffolk, and New York City counties in NYS; north of these counties, the species is undergoing population invasion and establishment. We recommend that mosquito surveillance programs monitoring the northward invasion of Ae. albopictus place BGS traps at sites chosen with respect to land cover.
  • Thumbnail Image
    La Crosse Virus Shows Strain-Specific Differences in Pathogenesis
    Wilson, Sarah N.; López, Krisangel; Coutermarsh-Ott, Sheryl; Auguste, Dawn I.; Porier, Danielle L.; Armstrong, Philip M.; Andreadis, Theodore G.; Eastwood, Gillian; Auguste, A. Jonathan (MDPI, 2021-03-29)
    La Crosse virus (LACV) is the leading cause of pediatric viral encephalitis in North America, and is an important public health pathogen. Historically, studies involving LACV pathogenesis have focused on lineage I strains, but no former work has explored the pathogenesis between or within lineages. Given the absence of LACV disease in endemic regions where a robust entomological risk exists, we hypothesize that some LACV strains are attenuated and demonstrate reduced neuroinvasiveness. Herein, we compared four viral strains representing all three lineages to determine differences in neurovirulence or neuroinvasiveness using three murine models. A representative strain from lineage I was shown to be the most lethal, causing >50% mortality in each of the three mouse studies. However, other strains only presented excessive mortality (>50%) within the suckling mouse neurovirulence model. Neurovirulence was comparable among strains, but viruses differed in their neuroinvasive capacities. Our studies also showed that viruses within lineage III vary in pathogenesis with contemporaneous strains, showing reduced neuroinvasiveness compared to an ancestral strain from the same U.S. state (i.e., Connecticut). These findings demonstrate that LACV strains differ markedly in pathogenesis, and that strain selection is important for assessing vaccine and therapeutic efficacies.
  • Thumbnail Image
    Large scale complete genome sequencing and phylodynamic analysis of eastern equine encephalitis virus reveal source-sink transmission dynamics in the United States
    Tan, Yi; Lam, Tommy Tsan-Yuk; Heberlein-Larson, Lea A.; Smole, Sandra C.; Auguste, A. Jonathan; Hennigan, Scott; Halpin, Rebecca A.; Fedorova, Nadia; Puri, Vinita; Stockwell, Timothy B.; Shilts, Meghan H.; Andreadis, Theodore G.; Armstrong, Philip M.; Tesh, Robert B.; Weaver, Scott C.; Unnasch, Thomas R.; Ciota, Alexander T.; Kramer, Laura D.; Das, Suman R. (American Society for Microbiology, 2018-04-04)
    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 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.
  • Thumbnail Image
    Local persistence of novel regional variants of La Crosse virus in the Northeast USA
    Eastwood, Gillian; Shepard, John J.; Misencik, Michael J.; Andreadis, Theodore G.; Armstrong, Philip M. (2020-11-11)
    Background La Crosse virus (LACV) (genus Orthobunyavirus, family Peribunyaviridae) is a mosquito-borne virus that causes pediatric encephalitis and accounts for 50–150 human cases annually in the USA. Human cases occur primarily in the Midwest and Appalachian regions whereas documented human cases occur very rarely in the northeastern USA. Methods Following detection of a LACV isolate from a field-collected mosquito in Connecticut during 2005, we evaluated the prevalence of LACV infection in local mosquito populations and genetically characterized virus isolates to determine whether the virus is maintained focally in this region. Results During 2018, we detected LACV in multiple species of mosquitoes, including those not previously associated with the virus. We also evaluated the phylogenetic relationship of LACV strains isolated from 2005–2018 in Connecticut and found that they formed a genetically homogeneous clade that was most similar to strains from New York State. Conclusion Our analysis argues for local isolation and long-term persistence of a genetically distinct lineage of LACV within this region. We highlight the need to determine more about the phenotypic behavior of these isolates, and whether this virus lineage poses a threat to public health.