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ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » ABADRU » Research » Publications at this Location » Publication #321074
Title: Effect of environmental temperature on the ability of Culex tarsalis and Aedes taeniorhynchus (Diptera: Culicidae) to transmit Rift Valley fever virus

Author
item TURELL, MICHAEL - Us Army Medical Research Institute
item Cohnstaedt, Lee
item Wilson, William - Bill

Submitted to: Vector-Borne and Zoonotic Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2020
Publication Date: 5/26/2020
Citation: Turell, M.J., Cohnstaedt, L.W., Wilson, W.C. 2020. Effect of environmental temperature on the ability of Culex tarsalis and Aedes taeniorhynchus (Diptera: Culicidae) to transmit Rift Valley fever virus. Vector-Borne and Zoonotic Diseases. 20 (6). https://doi.org/10.1089/vbz.2019.2554.
DOI: https://doi.org/10.1089/vbz.2019.2554

Interpretive Summary: Rift Valley fever virus (RVFV) causes severe disease in domestic animals such as cattle, goats, and sheep and may cause illness in humans (with about a 1% case fatality rate). The virus has spread from Africa to Asia and is a risk to spread to Europe and the Americas. Environmental temperature can significantly affect the ability of mosquitoes to transmit viruses with warmer temperatures likely increasing virus transmission. However, these effects are not consistent among viruses or mosquito species. Therefore, we evaluated the effect of temperature (14-30ºC) on infection, dissemination, and transmission rates on two species of mosquitoes. The mosquitoes were infected by feeding on RVFV infected hamsters. Temperature had a large effect on one species of mosquito but not the other, leading to the conclusion that virus infection can vary greatly between mosquito species and need to be investigated at a virus and mosquito species specific level. The effects of environmental factors, such as ambient temperature, need to be taken into account when developing models for viral persistence and spread in nature.

Technical Abstract: Rift Valley fever virus (RVFV) causes severe disease in domestic ungulates (cattle, goats, and sheep) and a febrile illness in humans (with about a 1% case fatality rate). This virus has been spreading geographically, and there is concern of it spreading to Europe or the Americas. Environmental temperature can significantly affect the ability of mosquitoes to transmit an arbovirus. However, these effects are not consistent among viruses or mosquito species. Therefore, we evaluated the effect of incubation temperatures ranging from 14-30ºC on infection, dissemination, and transmission rates for Culex tarsalis Coquillett and Aedes taeniorhynchus (Wiedemann) allowed to feed on hamsters infected with RVFV. Engorged mosquitoes were randomly allocated to cages and placed in incubators maintained at 14, 18, 22, 26, or 30ºC. While infection rates detected in Cx. tarsalis increased with increasing holding temperature, holding temperature had no effect on infection rates detected in Ae. taeniorhynchus. However, for both species, the percentage of mosquitoes with a disseminated infection after specific extrinsic incubation periods (7, 10, 14, 17, or 21 days), increased with increasing incubation holding temperature, even after adjusting for the apparent increase in infection rate in Cx. tarsalis. The effects of environmental factors, such as ambient temperature, need to be taken into account when developing models for viral persistence and spread in nature.