The 1988-1990 epizootic of yellow fever in Trinidad: virological aspects

ABSTRACT

Sylvatic yellow fever virus activity occurred in Trinidad between December, 1988 and January, 1990. It was first detected in the Trinity Hills area of Guayaguayare in the south eastern forest of the island and subsequently spread west to Moruga and north to Fishing Pond. Surveillance activities in these areas resulted in the collection of over 18,000 mosquitoes and seven monkeys which were referred to the CAREC laboratories for viral investigation. Six pools of mosquitoes yielded yellow fever virus in December, 1988 and January, 1989. Isolations were made from Haemagogus janthinomys (five pools) and Sabethes chloropterus (one pool). Extensive collections in other areas failed to yield virus. Three Alouatta monkeys proved to be infected with yellow fever. These were all Alouatta sp. and were submitted to the laboratory in February and March of 1989 and January of 1990. Thorough virological investigation of febrile persons, with and without liver involvement, showed no evidence to spread to the human population either before or during the epizootic. This was attributed to the high level of immunization achieved in the population following the yellow fever outbreak of 1978-1980.