Rift Valley Fever Vectors Research Articles

First isolation of the Rift Valley fever virus from Culex poicilipes (Diptera: Culicidae) in nature.

Following the reemergence of Rift Valley fever (RVF) virus in southeastern Mauritania in 1998, an entomological survey was undertaken in the boundary area in Senegal to assess the extent of the virus circulation. During this study, RVF virus (36 strains) was isolated for the first time from Culex poicilipes in nature. The possible role of Cx. poicilipes as an RVF vector is discussed regarding its biology and ecology.

New vectors of Rift Valley fever in West Africa.

After an outbreak of Rift Valley fever in Southern Mauritania in 1987, entomologic studies were conducted in a bordering region in Sénégal from 1991 to 1996 to identify the sylvatic vectors of Rift Valley fever virus. The virus was isolated from the floodwater mosquitoes Aedes vexans and Ae. ochraceus. In 1974 and 1983, the virus had been isolated from Ae. dalzieli. Although these vectors differ from the main vectors in East and South Africa, they use the same type of breeding sites and also feed on cattle and sheep. Although enzootic vectors have now been identified in West Africa, the factors causing outbreaks remain unclear.

Susceptibility of selected strains of Australian mosquitoes (Diptera: Culicidae) to Rift Valley fever virus.

We evaluated the ability of selected strains of the Australian mosquitoes, Aedes notoscriptus (Skuse), Ae. vigilax (Skuse), Culex annulirostris Skuse, and Cx. quinquefasciatus Say, to function as potential vectors of Rift Valley fever (RVF) virus, should that virus be introduced accidentally into Australia. After feeding on a hamster with a viremia of 10(7) plaque-forming units/ml of blood, Ae. notoscriptus and Cx. annulirostris were the most susceptible, with infection rates of 86 and 55%, respectively. Female Ae. vigilax and Cx. quinquefasciatus also were susceptible, with infection rates of 38 and 30%, respectively. All of these species transmitted RVF virus by bite 7-10 d after intrathoracic inoculation, and all, except Cx. quinquefastiatus (not tested), transmitted RVF virus 10-16 d after oral exposure. The presence of competent mosquito vectors for RVF virus in Australia indicates the potential for RVF virus epizootics to occur should this virus be introduced into Australia.

Identification of central Kenyan Rift Valley Fever virus vector habitats with landsat TM and evaluation of their flooding status with airborne imaging radar

Rift Valley Fever (RVF) is a mosquito-borne virus that affects livestock and humans in Africa. Landsat Thematic Mapper (TM) data are shown to be effective in identifying dambos, intermittently flooded areas that are potential mosquito breeding sites, in an area north of Nairobi, Kenya. Positive results were obtained from a limited test of flood detection in dambos with airborne high resolution L, C, and X band multipolarization synthetic aperture radar (SAR) imagery. L and C bands were effective in detecting flooded dambos, but LHH was by far the best channel for discrimination ( p < 0.01) between flooded and nonflooded sites in both sedge and short grass environments. This study demonstrates the feasibility of a combined passive and active remote sensing program for monitoring the location and condition of RVF vector habitats, thus making future control of the disease more promising.

Possible vectors of Rift Valley fever in Kenya

Possible vectors of Rift Valley fever in Kenya