West Nile season has arrived

Within the last week, mounting evidence indicates West Nile virus (WNV) season is upon us.

The California Department of Public Health reported the first confirmed human case in an individual from Santa Barbara County, who after hospitalization is now at home recovering.

Jerry Oser of the Owens Valley Mosquito Abatement Program in Inyo County has reported a positive mosquito pool, collected near the Bishop Airport.

Steve Ganong of the Mammoth Lakes Mosquito Abatement District in Mono County reports numerous traps with high numbers of Culex Tarsalis mosquitoes, an efficient vector (carrier and transmitter) of the virus.

So far this summer, there have not been any equine (horse) cases in California, but evidence of the presence of the West Nile virus has been reported in 17 counties (positive dead birds, chickens, or mosquito pools). This is somewhat less than last year. However, don’t be lulled to sleep by the low numbers – with our late spring and summer, the worst is yet to come.

West Nile virus is most commonly transmitted to humans and animals by the bite of a mosquito harboring the virus. The risk of serious illness to most people is low. However, some individuals – less than 1% – will develop severe neurologic illness such as encephalitis or meningitis. People 50 years of age or older have a higher chance of getting sick and are more likely to develop severe symptoms. Recent data also indicate that those with diabetes and/or hypertension are at greatest risk of serious disease.

–Richard Johnson, Mono County Public Health Officer