Submitted to: Journal of Medical Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/3/2008
Publication Date: 9/1/2008
Citation: Bennett, K.E., Hopper, J.E., Stuart, M.A., West, M.S., Drolet, B.S. 2008. Blood Feeding Behavior of Vesicular Stomatitis Virus Infected Culicoides Sonorensis (Diptera: Ceratopogonidae). Journal of Medical Entomology. 2008 Sep 45(5):921-6 Interpretive Summary: Culicoides sonorensis (Diptera: Ceratopogonidae) is the primary vector of Bluetongue virus in North America and has been shown to be a competent vector of Vesicular Stomatitis virus (VSV). To determine whether infection with VSV affects blood feeding behavior, midges were injected with VSV-infected or virus-free cell lysate and held two, three, or four days before being offered a non-infectious blood meal. Midges inoculated with VSV had significantly lower blood feeding rates at two days post inoculation (PI), but not at three or four days. A virus growth curve reveals that this reduction in feeding correlates to peak virus titer in the insect. Midges fed 3 days post inoculation fed significantly better when given 60 min to feed. This was not seen on days 2 and 4 PI.
Technical Abstract: To determine whether vesicular stomatitis virus (VSV) infection of Culicoides sonorensis affects subsequent blood feeding behavior, midges injected with either virus-infected or virus-free cell lysates were allowed to blood feed for short (10 min) or long (60 min) periods of time on days 2, 3, and 4 post inoculation (PI). Using a generalized linear mixed model, significant effects on blood feeding rate were observed for midges held 2 and 4 days PI based on VSV infection status and the interaction of VSV infection status with hold time. When this was further analyzed by hold time, the significant difference in feeding rates was accounted for by midges held 2 days PI, at which time significantly fewer VSV-infected midges fed regardless of feeding duration. This corresponded to a peak virus titer of injected midges at 2 days PI. A significant effect on blood feeding rate was found for midges held 3 days PI based on blood feeding duration. Significantly more midges fed when allowed 60 min to feed. This was not seen on days 2 and 4 PI and was not dependent on VSV-infection status. How changes in blood feeding behavior of infected insects might impact virus transmission is discussed.