Western equine encephalitis virus

WEE was discovered in 1930 when a number of horses in the San Joaquin Valley of California, USA died of a mysterious encephalitis. Karl Friedrich Meyer investigated but was not able to isolate the pathogen from necropsies of horses that had been dead for some time and needed samples from an animal in the earlier stages of disease. When the team heard of a horse that appeared to have encephalitis, its owner threatened to shoot the scientists. However Meyer was able to convince the farmer's wife that the horse was dying anyway, and to secretly signal him when the farmer was asleep in exchange for $20 (as this was during the Great Depression, this was a substantial amount of money). Meyer and his colleagues hid in the bushes until the signal, euthanized the horse and stole its head. They successfully isolated WEEV from the brain tissue. ==Biological weapon==

Western equine encephalitis virus was one of more than a dozen agents that the United States researched as potential biological weapons before the nation suspended its biological weapons program. == Clinical Features ==

Incubation and Symptoms The incubation period for the Western equine encephalitis virus is 5-10 days. Although the infection is primarily asymptomatic, individuals at risk (children aged 2 years and younger, and adults older than 60), may develop a more serious course of illness. Symptoms of WEE may range from a febrile illness including fever, chills, malaise, weakness, and myalgias to more severe course including aseptic meningitis or encephalitis leading to coma or even death. Additionally, reverse transcription polymerase chain reaction (RT-PCR), isolation from tissue cultures, immunohistochemistry, hemagglutination inhibition (of paired samples) or complement fixation (of paired samples) are viable methods. The presence of IgM antibodies may correlate with an acute infection and may be detected within 1 to 3 weeks from the onset of symptoms. IgG antibodies are generally detectable within 1 to 3 weeks after infection with peaks at 1 to 2 months. IgG antibody titers are generally an indication of exposure and, depending on the titer, may indicate a recent infection. Testing for WEE cross-reacts with St. Louis encephalitis virus, making the two infections hard to distinguish from one another. == See also ==