Infectious Disease
California reports four new cases of West Nile virus
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Jul 21, 2006 - 8:22:00 PM

STATE HEALTH OFFICER ANNOUNCES FOUR NEW CASES OF WEST NILE VIRUS IN CALIFORNIA

SACRAMENTO - Four individuals, one each from Kern, Stanislaus, San Joaquin and Sutter counties, have been confirmed with West Nile virus (WNV) infections this week in California, State Public Health Officer Dr. Mark Horton announced today. The individuals from San Joaquin County and Kern County developed neurological disease. Three of the individuals were hospitalized and released.

"We have been experiencing a heat wave with temperatures in some areas consistently above 100 degrees, which is conducive to mosquito breeding and virus replication," Horton said. "As a result, we expect a rapid rise in mosquito activity over the next few weeks. Californians really need to step up their efforts to protect themselves from mosquito bites when outside, especially those individuals who work outdoors, such as construction and landscaping workers."

The four confirmed cases this week increase the number of human WNV infections reported so far this year in California to five. The first human case was confirmed last month in Kern County . In 2005, a total of 935 human WNV infections were reported in 40 counties, including 19 deaths.

So far this year, WNV has been detected in 26 of California 's 58 counties in 151 dead birds, 62 mosquito pools and seven sentinel chickens. The California Department of Food and Agriculture has reported three case of WNV in horses, including two in Merced County and one in Tulare County . The Tulare County horse and one of the horses in Merced County died.

The California Department of Health Services (CDHS) uses a geographic information system to map dead bird reports. The 23,000 dead bird reports received from the public have helped identify areas with high concentrations of mosquitoes with WNV. With this information, local mosquito control agencies have been able to target their efforts to reduce mosquito populations and prevent human illness.

In the 2005-2006 budget, the Governor included $12 million to enhance and expand mosquito control efforts statewide. The Governor invested an additional $3 million in the 2006-2007 budget to supplement existing mosquito control activities in high-risk areas and "hot spots".

WNV is transmitted to humans and animals through a mosquito bite. Mosquitoes become infected when they feed on infected birds. Health officials emphasize that the risk of serious illness to humans is low. Most individuals who are infected with WNV will not experience any illness. A review of data collected by CDHS' Viral and Rickettsial Disease Laboratory in Richmond indicate that people with diabetes and or hypertension are at increased risk to develop more serious complications from WNV.

Horton reminded Californians that the three most effective ways to prevent WNV are:

- Apply insect repellent containing DEET, picaradin or oil of lemon eucalyptus, according to label instructions.

- Ensure doors and windows have tight-fitting screens. Repair or replace screens that have tears or holes.

- Eliminate all sources of standing water that can support mosquito breeding.

For more information about WNV and to report dead birds, call 1-877-WNV-BIRD (1-877-968-2473) or visit www.westnile.ca.gov . The Web site is updated every Tuesday and Friday at 4 p.m. PDT .

Source: http://www.mosquitoes.org/wnvupdate.htm