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ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » ABADRU » Research » Publications at this Location » Publication #249664
Title: Potential for North American Mosquitoes (Diptera: Culicidae) to Transmit Rift Valley Fever Virus

Author
item TURELL, MICHAEL - Us Army Medical Research Institute
item Wilson, William - Bill
item Bennett, Kristine

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2010
Publication Date: 9/1/2010
Citation: Turell, M.J., Wilson, W.C., Bennett, K.E. 2010. Potential for North American Mosquitoes (Diptera: Culicidae) to Transmit Rift Valley Fever Virus. Journal of Medical Entomology. 47(5):884-889. doi.org/10.1603/ME10007.

Interpretive Summary: To determine which biting insects should be targeted for control should Rift Valley fever virus (RVFV) be detected in North America, we evaluated Culex erraticus, Culex erythrothorax, Culex pipiens, Culex quinquefasciatus, Culex tarsalis, Aedes dorsalis, Aedes vexans, Anopheles quadrimaculatus, and Culicoides sonorensis from the Western, Midwestern, and Southern United States for their ability to become infected with and transmit RVFV. Although several of these species became infected with RVFV, and some were able to transmit at a low level, Cx tarsalis was the only species that efficiently transmitted the virus. In addition to laboratory vector competence, factors such as seasonal density, feeding preference, longevity, and foraging behavior need to be considered when determining the role these species could play in RVFV transmission.

Technical Abstract: To determine which biting insects should be targeted for control should Rift Valley fever virus (RVFV) be detected in North America, we evaluated Culex erraticus, Culex erythrothorax, Culex pipiens, Culex quinquefasciatus, Culex tarsalis, Aedes dorsalis, Aedes vexans, Anopheles quadrimaculatus, and Culicoides sonorensis from the Western, Midwestern, and Southern United States for their ability to transmit RVFV. Specimens were allowed to feed on adult hamsters inoculated with RVFV, incubated for 7-21 days at 26oC, and then allowed to refeed on susceptible hamsters and tested to determine infection, dissemination, and transmission rates. Other specimens were inoculated intrathoracically, held for 7 days, and then allowed to feed on a susceptible hamster to check for a salivary gland barrier. When exposed to hamsters with viremias >108.8 plaque-forming units/mL of blood, Cx. tarsalis transmitted RVFV efficiently (infection rate = 93%, dissemination rate = 56%, and estimated transmission rate = 52%). In contrast, when exposed to the same virus dose, none of the other species tested transmitted RVFV efficiently. Estimated transmission rates for Cx. erythrothorax, Cx. pipiens, Cx. erraticus, and Ae. dorsalis were 10, 8, 4, and 2%, respectively, and for the remaining species were <1%. With the exception of Cx. tarsalis and Cx. pipiens, all species tested had moderate to major salivary gland barriers. None of the C. sonorensis became infected and none of the Anopheles quadrimaculatus tested transmitted RVFV by bite, even after intrathoracic inoculation, indicating that these species would not be competent vectors of RVFV. In addition to laboratory vector competence, factors such as seasonal density, feeding preference, longevity, and foraging behavior need to be considered when determining the role these species could play in RVFV transmission.