Rift Valley fever virus-infected mosquito ova and associated pathology: possible implications for endemic maintenance.

Background: Endemic/Enzootic maintenance mechanisms like vertical transmission (pathogen passage from infected adults to their offspring) are central in the epidemiology of zoonotic pathogens. In Kenya, Rift Valley fever virus (RVFV) may be maintained by vertical transmission in ground-pool mosquitoes such as . RVFV can cause serious morbidity and mortality in humans and livestock.

Non-West Nile virus-associated mortality in a population of American crows (Corvus brachyrhynchos): a gross and histopathologic study.

The American crow (Corvus brachyrhynchos) is a common urban and rural inhabitant of the Northeast and Midwest United States that is commonly infected with West Nile virus (WNV). The current study was initiated to determine non-WNV-associated causes of mortality in the American crow. All animals (40/40) tested negative for WNV infection via polymerase chain reaction and had no evidence of infection based on immunohistochemistry.

Vector competence of selected African mosquito (Diptera: Culicidae) species for Rift Valley fever virus.

Outbreaks of Rift Valley fever (RVF) in Egypt, Yemen, and Saudi Arabia have indicated the potential for this disease to spread from its enzootic areas in sub-Saharan Africa. Because little is known about the potential for most African mosquito species to transmit RVF virus (family Bunyaviridae, genus Phlebovirus, RVFV), we conducted studies to determine the vector competence of selected African species of mosquitoes for this virus. All eight species tested [Aedes palpalis (Newstead), Aedes mcintoshi Huang, Aedes circumluteolus (Theobald), Aedes calceatus Edwards, Aedes aegypti (L.

Host-feeding patterns of Culex mosquitoes in relation to trap habitat.

Mosquito feeding patterns identify vertebrate species potentially involved in the amplification of West Nile virus. In New York, northern cardinals (Cardinalis cardinalis) were the predominant hosts in most habitats. Crow (Corvus sp.

Acquisition of Lyme disease spirochetes by cofeeding Ixodes scapularis ticks.

Ixodes scapularis ticks acquired spirochetes while cofeeding with Borrelia burgdorferi-infected nymphs (donors) on uninfected naive gerbils. Overall, 19% (67 of 345) of the recipient nymphs randomly exposed to gerbils with donor nymphs acquired spirochetes by fluorescent antibody (FA) tests, 18% (62 of 345) by the polymerase chain reaction. In a second experiment, donor nymphs were placed on the left ears, recipient nymphs were placed on the left and right ears, and xenodiagnostic larvae were placed on the gerbils' backs.