West Nile Virus ActivityConfirmed Cases
2010 YTD vs 2009 YTD
As of 10/19/10
|(2010 YTD-Year to date corresponds to the
same time last year)
|2009 YTD||2010 YTD|
|# of Counties||42||35|
What is West Nile Virus?
West Nile virus (WNV) is a potentially serious illness. Experts believe WNV is established as a seasonal epidemic in North America that flares up in the summer and continues into the fall. WNV season runs June 1-Nov. 1.
How WNV IS Spread to Humans?
WNV virus is transmitted to humans and animals through a mosquito bite. Mosquitos become infected when they feed on infected birds. Human-to-human transmission of WNV does not occur. However, human WNV infections have been associated with blood transfusions and organ transplants.
Control Activities in Alameda County
West Nile Virus activity in California was very mild in 2010. Alameda County had no human cases of WNV. Only one bird tested positive for WNV; no squirrels or mosquito pools tested positive.