SACRAMENTO - Five San Bernardino County residents have tested positive for West Nile virus (WNV) infection, State Health Director Sandra Shewry announced today. The new reported cases of WNV increase California's total to six this year, all in San Bernardino County.

"Significant West Nile virus activity has been detected in birds and mosquitoes in San Bernardino County, where these individual reside," Shewry said. "West Nile virus is spread primarily from the bite of an infected mosquito. The fact that we now have five new human cases in the same general area should serve as an important reminder for the public to take preventive measures against mosquito bites."

The five individuals are a 64-year-old female, 19-year-old male, 17-year-old male and two 12-year-old males. In May, they experienced fever, muscle aches, headache and a rash. None were hospitalized. On June 8, the California Department of Health Services (CDHS) announced the state’s first confirmed human case this year, a 40-year-old female.

In addition to San Bernardino County, WNV has been detected in birds or mosquitoes in Imperial, Los Angeles, Orange, Riverside and Ventura counties this year. Health officials emphasized that the risk of serious illness to humans is low. Most individuals who are infected with WNV will not experience any illness. Approximately 10 percent to 15 percent of infected individuals will have only mild to moderate symptoms, such as fever, headache and body aches. Less than 1 percent of individuals will develop serious neurologic illness such as encephalitis and meningitis. The elderly and those with lowered immune systems are more susceptible to serious illness.

In recognition of the public health threat posed by WNV, Gov. Arnold Schwarzenegger included $977,000 in state funds in the May revision of the proposed state budget to boost California’s efforts to control the spread of WNV. The funds would be used to expand surveillance activities to enhance detection of the virus and prompt control efforts.

WNV is transmitted to humans and animals through a mosquito bite. Mosquitoes become infected when they feed on infected birds. Individuals can reduce their risk of mosquito-borne diseases by taking these precautions:

• Avoid spending time outside when mosquitoes are most active, especially at dawn and the first two hours after sunset.

• When outdoors, wear long pants and long-sleeved shirts.

• Apply insect repellant containing DEET according to label instructions.

• Make sure that 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.

• Contact your local mosquito and vector control agency if there is a significant mosquito problem where you live or work.

The state's current interagency surveillance system for WNV includes testing of dead birds, mosquitoes and sentinel chickens. Shewry asked the public to assist in the extensive monitoring effort for the virus by reporting any crows, ravens, magpies and jays that have been dead for less than 48 hours to CDHS' toll-free hotline: 1-877-WNV-BIRD. Individuals should take note of the bird's location and condition before calling for further instructions, including assistance with identifying the type of bird found. The bird should show no signs of decomposition or maggot infestation. While there is no evidence that people can get WNV from handling live or dead infected birds, individuals should not attempt to catch or handle them. If the local agency is unable to pick up the bird, individuals should use gloves, a shovel or newspaper to put it in a plastic bag and place it in the trash.

Through June 17 this year, WNV has been found in 492 dead birds, including 220 in San Bernardino County, 207 in Los Angeles County, 61 in Riverside County, three in Orange County and one in Ventura County. In addition, the virus has been detected in 59 "pools" of mosquitoes collected in Imperial, Los Angeles, Riverside and San Bernardino counties and seven sentinel chickens located near the Salton Sea in Riverside County. The mosquitoes from Imperial County were collected on June 1 and represent the first detection of WNV in that county this year.

The current surveillance program to monitor for WNV in California has been established by CDHS in collaboration with the University of California, Davis, California Department of Food and Agriculture, local mosquito and vector control districts and other state and local agencies.

Since horses are susceptible to WNV and a vaccine is available for horses, horse owners are advised to contact their veterinarians about timely vaccinations.

For more information about WNV in California or to report dead birds online, visit CDHS' Web site at http://www.westnile.ca.gov/.

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