LOS ANGELES, July 24 (Xinhua) -- Three men and a male child were confirmed on Thursday as this year's first human cases of West Nile virus in the Los Angeles area.

    Two men and the child were hospitalized this month for meningitis after developing symptoms of the virus, according to the Los Angeles County Department of Public Health.

    The third man did not show any symptoms, but his infection was detected when he donated blood, said the department.

    The patients were all recovering, said health officials who declined to identify them.

    "West Nile virus can appear anywhere in Los Angeles County or around the state," said Dr. Jonathan Fielding, the county director of public health. "Our warm weather encourages mosquito breeding, but the weather is also an invitation for individuals to spend more time outdoors. When they do, residents should take precautions to avoid mosquito bites."

    The Los Angeles County cases bring to 11 the number of human West Nile virus cases in California this year.

    In 2007, there were 43 human cases and five deaths in Los Angeles County due to West Nile virus.

    The virus is spread to humans from the bite of an infected mosquito. About 80 percent of infected people do not exhibit symptoms, but 20 percent can develop symptoms such as high fever, headache, body aches, nausea, vomiting and skin rashes.