ABSTRACT

Eastern equine encephalitis virus, an alphavirus, is the causative agent of eastern equine encephalitis, an arthropod-borne disease endemic to North, Central, and South America. In addition to horses, humans, and birds, the eastern equine encephalitis virus can also infect reptiles. Although experimental studies have demonstrated that reptiles can remain viremic for longer periods of time than mammals and birds, as well as remain viremic through hibernation, the overall role of reptiles in the epidemiology for the virus is unclear. A cross-sectional study was performed to estimate the seroprevalence of eastern equine encephalitis virus in chelonians from southeastern Louisiana. Blood was collected from 117 chelonians in southeastern Louisiana in the summer of 2000 (n=76) and the spring of 2001 (n=41). Hemagglutination inhibition assay and plaque reduction neutralization test were utilized to determine exposure. Six (5%) of the 117 chelonians were seropositive for eastern equine encephalitis virus on hemagglutination inhibition; however, plaque reduction neutralizing antibody titers specific for eastern equine encephalitis virus, western equine encephalitis virus, and Venezuelan encephalitis virus were negative for these six samples. While there was no evidence of eastern equine encephalitis virus, these findings suggest that these chelonians may have nonspecific antibody production to an undefined alphavirus. This study was the first attempt to determine the seroprevalence of eastern equine encephalitis virus in wild chelonians from Louisiana.