Culex tarsalis is a competent vector species for Cache Valley virus

Area of Science:

• Arbovirology
• Medical Entomology
• Veterinary Virology

Background:

• Cache Valley virus (CVV) is an orthobunyavirus endemic in North America.
• CVV causes significant agricultural losses in ruminants, particularly sheep, due to abortion and embryonic lethality.
• Recent reports of severe neurotropic diseases in humans highlight the increasing public health importance of CVV.

Purpose of the Study:

• To determine the vector competence of three mosquito species: Culex pipiens, Culex tarsalis, and Culex quinquefasciatus.
• To identify potential bridge vectors responsible for transmitting CVV from vertebrate hosts to humans.

Main Methods:

• Mosquitoes (Culex pipiens, Cx. tarsalis, Cx. quinquefasciatus) were exposed to CVV.
• Infection, dissemination, and transmission capabilities were assessed in each species.
• Viral RNA detection in mosquito saliva was performed.

Main Results:

• Culex tarsalis demonstrated susceptibility to CVV infection and disseminated the virus.
• Culex pipiens and Cx. quinquefasciatus were found to be highly refractory to CVV infection.
• Detection of viral RNA in the saliva of infected Cx. tarsalis confirmed its competence as a vector.

Conclusions:

• Culex tarsalis is identified as a competent vector for Cache Valley virus.
• This finding enhances understanding of CVV transmission cycles and its potential role in human disease.