From 20072016 there were no reported cases of EEE in humans in Maryland; however, there have been EEE cases reported in horses and in mosquitoes, for example, Culiseta melanura
and Culex salinarius.
The enzootic cycle of this virus is maintained between birds and mosquitoes (primarily Culiseta melanura
) and then transmitted to mammals by mosquitoes that blood feed on both avian and mammalian hosts (NCDPH, 2009).
EEEV is perpetuated in an enzootic cycle involving ornithophilic mosquitoes (primarily Culiseta melanura
) and passerine birds in freshwater swamps (2,3).
Table 1: Cases of arboviral disease reported to Centers for Disease Control and Prevention Major US arboviruses that cause encephalitis Virus Primary mosquito Geographic area vector West Nile virus Culex and other 48 states (continenal (WNV) U.S.) Eastern Equine Culiseta melanura
Eastern seaboard, encephalitis (EEE) Gulf Coast, Midwest virus Western Equine Culex tarsalis; also Western U.
EEE was first isolated in the United States in 1933 and is transmitted by Culiseta melanura
, a mosquito that lives in fresh water swamps and rarely bites animals.
Intraspecific variation in key morphological characters of Culiseta melanura
EEEV is transmitted in marshes and swamps in an enzootic bird-mosquito-bird cycle primarily by the mosquito Culiseta melanura
. Bridge mosquito vectors (e.g., Coquillettidia perturbans, Aedes vexans, or Aedes sollicitans) transmit EEEV to humans and other mammals (1,2).
Enzootic circulation of EEEV in eastern North America is primarily supported by a variety of avian reservoirs in the order Passeriformes and by the highly ornithophilic mosquito vector, Culiseta melanura
, in freshwater swamp habitats.
The Culex species is a WNV vector, and EEE involves several species of mosquito vectors, including Culiseta melanura
, a bird-biting mosquito.
restuans (nine), Culiseta melanura
(three), unidentified Aedes/Oc.
Infection and transmission of Eastern equine encephlomyelitis virus with colonized Culiseta melanura