Surveillance and management of sylvatic yellow fever in Trinidad (1988-1989) - abstract

ABSTRACT

Howler monkey (Aloutta sp) deaths in the Southeastern forests of Trinidad were reported in December, 1988. This paper reports the laboratory and field investigations and preventive measures which were undertaken, in view of the known association between such deaths and yellow fever (YF) activity. A total of 47,640 adult mosquitoes were captured in several forest regions in Trinidad during the period December 1988 to October, 1989. Mosquitoes were identified, pooled and processed for virus isolation. Blood and organs from 5 dead Howler monkeys submitted between December 1988 and March, 1989 were examined for the presence of YF virus. Virus isolation was done by innoculation of material in AP61 (Ades pseudo-scutellaris) tissue culture and in 2-day-old Swiss albino mice, followed by identification of YF isolates by immunoflourescence, using monoclonal antibody and standard mouse neutralization tests, respectively. Fourty-four species of mosquito belonging to 14 genera were identified. From 654 mosquito pools, 6 YF isolates were obtained from only 2 species five isolates from haemagogus janthinomys (December, 1988) and 1, for the first time locally, from Sabethes chloropterus (January, 1989). YF virus was isolated from blood and organs of 2 Howler monkeys captured on February 22 and March 2, 1989. There were no human cases of YF. Yellow fever activity appeared to be confined to the southeast part of the island. Preventive measures included mass targeted YF immunization (400,000 doses administered in 3 months), intensified vector control operations and reduced human contact with forest mosquitoes by the existing ban on hunting (AU)