Lukas Lorenz

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We used a histologic technique to study multiple blood feeding in a single gonotrophic cycle by engorged Aedes aegypti (L.) that were collected weekly for 2 yr from houses in a rural village in Thailand (n = 1,891) and a residential section of San Juan, Puerto Rico (n = 1,675). Overall, mosquitoes from Thailand contained significantly more multiple meals (n(More)
Aspiration collections of adult Aedes aegypti (L.) were made weekly from inside and outside of houses for 3 yr in a rural Thai village (n = 9,637 females and n = 11,988 males) and for 2 yr in a residential section of San Juan, Puerto Rico (n = 5,941 females and n = 6,739 males). In Thailand, temperature and rainfall fell into distinct seasonal categories,(More)
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(More)
Arthropod-borne viruses were not previously believed to cause discernible pathologic changes in their natural mosquito vectors. We report cytopathologic lesions in the midgut of the mosquito, Culiseta melanura, 2 to 5 days after oral infection with eastern equine encephalomyelitis virus. Sloughing of densely staining, heavily infected epithelial cells into(More)
Artificial selection on strains of Aedes aegypti showing susceptibility and refractoriness to oral infection with yellow fever virus (YFV) suggests that there is a significant genetic component to this trait. Using a population with an average susceptibility of 15%, inbreeding of isofemale lines followed by individual selection produced susceptible (29%(More)
Two colonies of Aedes aegypti were established from two independent collections from Vero Beach, Florida. Eleven sequential generations of the first colony were tested for variation in oral susceptibility to infection with yellow fever virus (YFV). Each generation was also assayed for genetic variability at seven enzyme loci using electrophoretic(More)
Aedes aegypti (L.) were collected by aspiration once each week from in and around houses in a rural village in Chachoengsao Province. Thailand, during May 1990 to June 1991. Of the 1,230 specimens analyzed with a sandwich ELISA, 73% reacted to one or more of the seven hosts which we tested. Eighty-eight percent (789/896) of all detectable meals were(More)
We evaluated a histologic technique for its usefulness in detecting multiple blood feeding by Aedes aegypti (L.) in a single gonotrophic cycle. To standardize the procedure, we carried out a laboratory study in which 166 mosquitoes imbibed two blood meals at known intervals. Eighty percent (78/98) of the multiple meals were detected when the interval(More)
Culex nigripalpus females were given double and, in 2 cases, triple (interrupted) bloodmeals separated by various intervals. Mosquitoes given single meals served as controls. Using Azan-stained serial paraffin sections, we could identify multiple meals separated by 1-72 hr in 44 of 53 cases (84.6%). Among the histological parameters of importance in the(More)
To test the hypothesis that arbovirus infection or advancing age increases the attractiveness of avian hosts to vector mosquitoes, we used an olfactometer that measures the response of mosquitoes to the passive, vertical diffusion of host-related cues. St. Louis encephalitis or western equine encephalomyelitis virus infection in house sparrows (Passer(More)