California's first human death from West Nile virus (WNV)

Jul 26 2004

West Nile virus (WNV) has claimed the life of a 57-year old Orange County man, making him the first to die in California from the virus, Dr. Richard Joseph Jackson, state public health officer, announced today.

In addition, WNV has been detected for the first time in Butte, Kings, Mendocino, Sacramento, San Diego, San Joaquin, Tehama and Tulare counties, raising to 16 the number of counties where the virus has been detected, Jackson said. Tests conducted on dead birds in those counties were positive for the virus.

"The loss of this man is a sad reminder of the seriousness of West Nile virus," Jackson emphasized. "Although the risk of serious illness to most people is low, I urge residents to take steps now to protect themselves from mosquito bites and this virus."

The man was hospitalized with encephalitis in mid-June and died June 24. Preliminary tests for WNV were positive at a commercial laboratory. Further testing yesterday at the California Department of Health Services confirmed WNV infection.

To date, 35 Californians have tested positive for WNV, including 20 in San Bernardino County, eight in Los Angeles County, six in Riverside County and the individual who died in Orange County. WNV has also been detected in Imperial, Kern, Santa Clara and Ventura counties.

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 monitor and 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, sentinel chickens, horses and people. Jackson 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 this year as of today, WNV has been found in 980 dead birds, including 283 in San Bernardino County, 525 in Los Angeles County, 114 in Riverside County, 42 in Orange County, four in Sacramento County, three in Ventura County and one each in Butte, Kern, Kings, Mendocino, San Diego, San Joaquin, Santa Clara, Tehama and Tulare counties. In addition, the virus has been detected in 171 "pools" of mosquitoes collected in Imperial, Kern, Los Angeles, Orange, Riverside and San Bernardino counties and 75 sentinel chickens in Imperial, Los Angeles and Riverside counties.

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, local health departments and other state and local agencies.

WNV has also infected 26 horses in Riverside and San Bernardino counties. Eleven have died. 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/.