Update first cases:Los Angeles Prepares for Tough West Nile Virus Season

West Nile cases on rise in Southern California

Gerhard Goedhart, district manager of the Orange County Vector Control District, holds a jar of mosquitoes and larvae at a news conference Tuesday in Garden Grove. “The public in Southern California is threatened by this situation and must take this threat seriously,” he says of the rise in West Nile virus cases.

On Tuesday, San Bernardino County confirmed its first human case of the year. Seven new cases were reported in Riverside County this week. Since the beginning of the year, 12 people have been infected in Los Angeles County, nine in Orange County and two in San Diego County.

Thirty-nine cases of human West Nile virus have been confirmed in the state as of Tuesday. There have been no fatalities related to West Nile virus in California this year, but officials fear an outbreak between August and October, the peak period for infections.

Humans and animals contract West Nile virus from bites of infected mosquitoes, which contract it by feeding on birds that have the virus in their blood.

Most people who are infected by the virus do not become ill, but 1 in 5 people develop flu-like symptoms. In its most severe form, West Nile can cause encephalitis, meningitis and death.

Health officials on Tuesday urged Los Angelenos to brace for a tough West Nile virus season.

"The virus is definitely active, and people should be taking precautions," said Susanne Kluh, scientific technical services director for the Greater Los Angeles County Vector Control District (GLAVCD).

The GLAVCD is the largest of five vector control districts in the county, and covers the city of Los Angeles.

The Los Angeles County Board of Supervisors is expected to consider a motion by Supervisor Michael Antonovich to direct the departments of Public Health and Public Works to implement planned information and surveillance campaigns and to clear open waterways that could harbor mosquito breeding.

While cases of West Nile had been on a downswing the past two years, the virus appears to be on the rise again, Kluh said.

By this time last year, four dead birds and seven mosquito samples had tested positive for the disease in Los Angeles County. So far this year, 41 dead birds and 20 mosquito samples have tested positive, she said.