First isolation of Eastern equine virus from a case of encephalitis - abstract

ABSTRACT

A strain of Eastern Equine virus was isolated from a fatal human case of encephalitis for the first time in Trinidad in 1970. The virus was recovered from the blood and the brain of the patient. This new strain was found closely related to the TRVL prototype strain of Eastern Equine, isolated from Curlex nigripalpus in 1969. It was further identified at the National Communicable Diseases Centre as a South American strain of Eastern Equine. Validity of the isolate was confirmed by reisolation of the virus from the original materials. The etiological relationship of the virus to the patient's illness was established by the demonstration of a seroconversion to the isolated and to the TRVL prototype strain of Eastern Equine. A second case of human encephalitis occurred a week later in the same area. No virus was isolated from the acute phase blood. Diagnosis was made on the basis of an immuno-conversion to Eastern Equine. These two patients probably came into contact with the virus in the Santa Cruz Valley, which is situated in the Northern Range of Trinidad and fairly close to Port-of-Spain. In the Santa Cruz Valley, only three other humans have been found so far to have antibodies to Eastern Equine. They were living at the same spot where the first case supposedly became infected. Human survey as well as a field programme are stil in progress (AU)