As the number of people who test positive for infection with West Nile virus increases, health officials offer advice on prevention of West Nile virus infection. The virus can infect humans via mosquito bites that caught the disease from infected birds.

After the mosquito-transmitted disease claimed the lives of two people in Orange County, a Garden Grove man, age 64, and a 72-year-old Buena Park woman, Shasta County Deputy Health Officer Lou Anne Cummings announced the first confirmed human case of the mosquito-spread virus in Shasta County this year.

Most people who are infected with the virus show no symptoms, but about 20 percent of those infected experience symptoms similar with those of flu: fever, headache, body aches, nausea, vomiting. Severe symptoms include neck stiffness, high fever, stupor, disorientation, tremors, coma, convulsions, vision loss, muscle weakness, numbness, and paralysis, according to the CDC. In rare instances, it can cause severe illness and death. People older than 50, those with chronic medical affections and children are advised to be more attentive.

Individuals at any age should take precautions and should avoid contact with mosquitoes, use insect repellent when outdoors, and remove standing water from the yard, health officials and the Centers of Disease Control and Prevention recommend.

This year, the risk of human infection is nearly five times higher than in previous years. In order to avoid the contamination with the virus, people are advised by the authorities to avoid exposure at dusk and dawn, when mosquitoes are most active. Wear insect repellent containing permethrin or DEET on top of clothing and wear long sleeves and pants while outdoors. Over the past two years, the virus has been responsible for hundreds of deaths in the United States. In 2004, Southern California experienced 710 human West Nile virus cases and 21 people died.

The mosquito season may last until October, with its high point in mid-August.