Western equine encephalitis virus (WEE virus) has many characteristics in common with Eastern equine encephalitis virus, including being in the same family (Togaviridae) and genus (Alphavirus). However, it rarely is associated with disease in avian species other than turkeys.
WEE virus occurs mainly in western parts of the US and Canada, Central America, and South America. In the US and Canada, it is transmitted principally by Culex tarsalis, a mosquito vector that is common west of the Mississippi River. Disease control is based on decreasing exposure to mosquito vectors.
Clinical Findings in Western Equine Encephalitis Virus in Birds
Western equine encephalitis virus is a cause of encephalitis and high mortality rates in turkeys; affected turkeys exhibit somnolence, tremors, and leg paralysis. Turkey breeder hens may have decreased egg production.
Diagnosis of Western Equine Encephalitis Virus in Birds
Laboratory diagnosis of western equine encephalitis is accomplished using the same procedures used for eastern equine encephalitis virus.
Prevention and Control of Western Equine Encephalitis Virus in Birds
Prevention and control of western equine encephalitis is based on management procedures aimed at decreasing vector populations and locating production facilities away from vector habitats.
Zoonotic Risk of Western Equine Encephalitis Virus From Birds
Western equine encephalitis virus is a zoonotic agent and a potential cause of neurological disease in humans; however, most WEE virus infections in humans are subclinical. The case fatality rate for WEE virus infections is ~3%–7%.
