Jamestown Canyon virus spreads

The first human case of Jamestown Canyon virus infection detected in Montana suggests the infection spread more widely than previously thought, officials say. The study, published in the Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report, says increased Jamestown Canyon virus surveillance is needed to determine whether mosquito-borne viruses other than West Nile virus pose a risk to humans in the region. "The recent detection of a human Jamestown Canyon virus infection in Montana with illness onset in May means that mosquito borne virus transmission and disease begins in spring and lasts until the first freeze and indicates a much longer mosquito-borne disease risk than previously indicated by West Nile virus alone," the report says. "Jamestown Canyon virus is a mosquito borne pathogen that circulates widely in North America primarily between deer and a variety of mosquito species, but it can also infect humans, but reports of human Jamestown Canyon virus infections in the United States have been rare and confined to the Midwestern and northeastern states." Most reported illnesses caused by Jamestown Canyon virus have been mild, but moderate-to-severe central nervous system involvement including meningoencephalitis has been documented, federal health officials say.