Western equine encephalitis virus

Western equine encephalitis virus (WEEV) is a virus that belongs to the Togaviridae family and the Alphavirus genus. It is primarily transmitted by mosquitoes and can cause severe disease in humans and horses, known as Western equine encephalitis (WEE).

History

WEEV was first isolated in 1930 during an epidemic of equine encephalitis in the western United States. Since then, it has been identified in various regions across North and South America.

Transmission

WEEV is primarily transmitted through the bite of an infected mosquito. The virus has been found in several species of mosquitoes, but the most common vectors are the Culex tarsalis and Aedes melanimon. Birds serve as the primary reservoir host for the virus, with horses and humans being incidental hosts.

Clinical Manifestations

In humans, WEEV infection can range from asymptomatic to severe neurological disease. Symptoms typically begin with sudden onset of fever, headache, nausea, and vomiting, followed by neurological symptoms such as disorientation, seizures, and coma in severe cases. In horses, the disease can cause similar neurological symptoms and is often fatal.

Diagnosis and Treatment

Diagnosis of WEEV infection is typically based on clinical symptoms and confirmed by laboratory testing, such as serology or polymerase chain reaction (PCR). There is currently no specific antiviral treatment for WEEV infection. Management of the disease is primarily supportive, focusing on relieving symptoms and preventing complications.

Prevention

Prevention of WEEV infection primarily involves controlling mosquito populations and avoiding mosquito bites. Vaccines are available for horses, but there is currently no vaccine for humans.

See Also

• Eastern equine encephalitis virus
• Venezuelan equine encephalitis virus
• St. Louis encephalitis virus