Surveillance of eastern equine encephalomyelitis (EEE) in Jamaica

ABSTRACT

Since the outbreak of EEE in Jamaica in 1962, a continued surveillance for the virus has been maintained. It is known that birds act as reservoirs for the virus, and mosquitoes as vectors, consequently our attention directed towards ornithological and entomological investigations. Mosquitoes were caught regularly in the St. Thomas area during and after the outbreak. The surveillance among birds started some months later, and has continued to the present time. No mosquito was found infective with EEE virus, but Cache Valley virus, which is and arbovirus, was isolated from mosquitoes in the area. During the outbreak several birds (including domestic chickens) were bled and tested for circulating virus as well as for antibody to EEE virus. Fourteen of the 356 sera collected within six weeks after the outbreak showed a significant neutralizing titre to EEE virus. Among the wild birds caught subsequently, three of them (one resident and two migrants) showed sero-logical conversion to EEE virus in the St. Thomas area. About one year ago, the programme was extended to include the Black River area in St. Elizabeth. One bird in this area showed partial protection to EEE virus. These results seem to indicate that EEE virus is either endemic in the areas tested, or has been re-introduced by migrant birds. It is therefore necessary to maintain a continued surveillance to detect any activity of this virus(AU)