ABSTRACT
Twenty-eight populations representing a worldwide distribution of Aedes aegypti were tested for their ability to become orally infected with yellow fever virus (YFV). Populations had been analyzed for genetic variations at 11 isozyme loci and assigned to one of 8 genetic geographic groups of Ae. aegypti. Infection rates suggest that populations showing isozyme genetic relatedness also demonstrate similarity to oral infection rates with YFV. The findings support the hypothesis that genetic variation exists for oral susceptibility to YFV in Ae. aegypti.
Subject(s)
Aedes/microbiology , Insect Vectors/microbiology , Yellow fever virus/growth & development , Aedes/enzymology , Aedes/genetics , Africa , Animals , Asia , Central America , Female , Genetic Variation , Isoenzymes/analysis , Mouth/microbiology , South America , United States , West IndiesABSTRACT
Over a 7-year period in Trinidad, 9,514 birds were examined for avian pox and four species were found infected: the golden-headed manakin, Pipra erythrocephala (7% infected), the white-bearded manakin, Manacus manacus (5%), the violaceous euphonia Euphonia violacea (1%), and the bare-eyed thrush, Turdus nudigenis (less than 1%). The elaborate courtship displays of manakins may have a bearing on a "common source" type of infection. The apparently abrupt appearance of the disease at three localities in Trinidad in 1964 perhaps indicates introduction of the virus by migratory birds.
Subject(s)
Animal Population Groups/microbiology , Animals, Wild/microbiology , Fowlpox/epidemiology , Animals , Birds , Female , Fowlpox/transmission , Male , Sexual Behavior, Animal , Trinidad and TobagoABSTRACT
Three geographical strains of Aedes aegypti from Thailand (Amphur), East Africa (Kampala), and the West Indies (Santo Domingo) were compared for susceptibility to infection with low-passage yellow fever virus (French viscerotropic) as well as for ability to transmit virus by bite at varying extrinsic incubation periods. Santo Domingo strain appeared the most competent and Kampala the least when mosquitoes were exposed to a low level virus-infecting blood meal; at higher virus levels, a similar trend was noted but differences were less evident and in no case were the differences statistically significant. All three strains were infected with and transmitted yellow fever virus.
Subject(s)
Aedes/microbiology , Insect Vectors , Yellow fever virus , Africa, Eastern , Animals , Species Specificity , Thailand , West Indies , Yellow fever virus/growth & developmentABSTRACT
Pacui virus, originally obtained from forest rodents, was isolated 100 times from 61,437 specimens (658 pools) of the phlebotomine fly Lutzomyia flaviscutellata, collected from rodent-baited traps in the forests of Belem, Para, Brazil in the period October 1968 through September 1970. Isolations were made from engorged and unengorged females and from males (3 strains), and occurred in all 24 months. Pacui virus also was isolated from the blood of two wild rodents (Oryzomys), but not from 424 L. infraspinosa, 12,000 mosquitoes, or sentinel mice. Pacui virus neutralizing antibodies were detected in serum of six bait animals after exposure to biting flies in the forest, in 30% of wild rodents surveyed (including two from Amapa Territory), and in 10% of marsupials, but were absent in human survey sera and in bats. Low-passage Pacui virus produced viremia in and was lethal to infant mice by the subcutaneous route. L. flaviscutellata was most abundant in the dry season, in which period Pacui virus isolations increased. This fly is strongly attracted to rodents close to the ground. L. flaviscutellata also yielded single strains of Guama, Icoaraci, and BeAr 177325 viruses.