Field Investigations of Winter Transmission of Eastern Equine Encephalitis Virus in Florida

Abstract

Abstract. Studies investigating winter transmission of Eastern equine encephalitis virus (EEEV) were conducted in Hillsborough County, Florida. The virus was detected in Culiseta melanura and Anopheles quadrimaculatus in February 2012 and 2013, respectively. During the winter months, herons were the most important avian hosts for all mosquito species encountered. In collections carried out in the summer of 2011, blood meals taken from herons were still common, but less frequently encountered than in winter, with an increased frequency of mammalian-and reptile-derived meals observed in the summer. Four wading bird species (Black-crowned Night Heron [Nycticorax nycticorax], Yellowcrowned Night Heron [Nyctanassa violacea], Anhinga [Anhinga anhinga], and Great Blue Heron [Ardea herodias]) were most frequently fed upon by Cs. melanura and Culex erraticus, suggesting that these species may participate in maintaining EEEV during the winter in Florida.

Utilizing ecological niche modelling to predict habitat suitability of eastern equine encephalitis in Florida

“…The findings of this study do align, however, with Bingham et al (2014), who evaluated winter transmission patterns of EEEV in Florida and found that, overall, vector populations were abundant during the winter months and readily feeding. While the data utilized in this paper's research was related to dead-end host fatality, there appears to be an alignment between the habitat suitability predicted by the model and the findings of high activity in the winter months by Bingham et al (2014). This could indicate that EEEV activity in the peak season is partially determined by what the prior winter conditions were.…”

“…The model aligns with previous studies that emphasize the Florida panhandle as a hotspot for EEEV transmission, and this hotspot location has now been verified by both sentinel chicken infection data and equine fatality data. Heberlein-Larson et al (2019) emphasize in their study the theory that Florida represents a region that seeds the virus for transmission in other states in the Northeastbirds migrating through Florida to the Northeast may carry the virus with them, for example, as suggested by Bingham et al (2014). The panhandle, according to the model, represents a series of natural spaces where conditions are optimal not only for spread to avian hosts to continue the epizootic cycle but to equines, which are dead-end hosts where the infection can be fatal.…”

“…When a human contracts EEE, it is often fatal as there is no specific The state of Florida is one of the most extensively studied areas for EEEV as well as the state with the largest proportion of cases every year. Compared to other states, it has the most reported human casesone to two per yearand horse cases, having roughly 70 reported per year (Bingham et al 2014). Typically, in other states along the east coast and into the northeast, the EEEV viral cycle becomes dormant during the winter months.…”

“…Previous work has modelled EEEV distribution and perpetuation, typically utilizing information on mosquito vector location (Cupp et al 2003;Bigler et al 1976;Bingham et al 2014;Jacob et al 2010) as well as mapping locations or counts of potential bird vectors (Jacob et al 2010;Bingham et al 2014). Most of the modelling performed has been completed utilizing spatial distribution modelling such as spatial linear prediction models predicting abundance (Jacob et al 2010), density-based spatial clustering to identify clusters of habitats associated with the disease (Vander Kelen et al 2012b), and spatial risk modelling to identify areas of high risk for transmission (Vander Kelen et al 2014).…”

Ecology ofCuliseta Melanuraand Other Mosquitoes (Diptera: Culicidae) from Walton County, FL, During Winter Period 2013–2014

“…Throughout the range of NA-EEEV, the mosquito Culiseta melanura (Coquillett) is considered the primary enzootic vector of the virus (Howard et al 1988, Komar and Spielman 1994, Armstrong and Andreadis 2010. This mosquito species feeds mainly upon birds (Molaei et al 2006a, Burkett-Cadena et al 2008, Bingham et al 2012, although reptiles (Burkett-Cadena et al 2008) and mammals (Molaei et al 2006b, Bingham et al 2014) may be fed upon in some cases. A number of other mosquito species have been implicated as vectors of EEEV in the southern United States, although mostly as bridge vectors, transmitting the virus from amplification hosts (birds) to dead-end hosts (mammals).…”