Arbovirus studies in an evergreen seasonal marsh forest in Trinidad, West Indies

ABSTRACT

Studies carried out in Turure Forest, north-eastern Trinidad, from March, 1966, to March, 1969, resulted in the isolation of 462 arbovirus strains 198 Venezuelan equine encephalitis (VEE), 42 eastern equine encephalitis (EEE), 75 group C, 136 Guama group, 2 Ilheus, 1 St. Louis encephalitis, 5 Wyeomyia, 1 Maguari, 1 Cocal, and 1 Aruac, Strains of VEE were recovered most frequently from sentinel mice (109) and Culex portesi (82), and the same was true for the group C and Guana group isolates. EEE strains came from sentinel mice (30), C. pedroi (11), and C. portesi (1). Forest rodents yielded only 9 isolates, all group C and Guana group and all from Proechimys guyannensis and Oryzomys capito; however, 21 percent of 639 rodent sera had haemagglutination-inhibiting (HI) antibodies to one or more viruses. VEE HI antibodies were more common in O. capito that in P. guya nnensis. In complement-fixation (CF) tests, 32 percent of O. capito and 8 percent of P. guyannensis reacted with a Guama group antigen. Birds yielded 3 isolates, 2 Iheus and 1 St. Louis, but 10 percent of 1,414 Manacus manacus sera reacted with EEE antigen in HI test. Three of 4 horses had CF antibodies to EEE, and 54 percent of 158 human sera wer HI-positive for one or more of 9 antigens used, including VEE and EEE (AU)