Riverside County reports first human case of West Nile this year

Riverside County reported its first human case of West Nile Virus this year.

The patient, a minor from western Riverside County, is hospitalized but expected to make a full recovery, county health officials said.

According to the California Department of Public Health (CDPH), two cases of West Nile virus have been reported in humans in California this year.

“While West Nile is rarely life-threatening, it can occasionally be serious,” said Riverside County Public Health Officer Dr. Geoffrey Leung. “The West Nile virus is spread by mosquito bites, and there are steps you can take to reduce your risk of being bitten.”

West Nile virus transmission occurs after mosquitoes become infected when they feed on infected birds, and then transmit the virus to humans and animals through a bite.

Infections typically happen in summer and early fall when temperatures are warm, the air is damp and mosquitoes are active.

Leung provided the following recommendations to help prevent mosquito-borne illness:

• Apply insect repellent with EPA-registered active ingredients DEET, picaridin, IR3535, or oil of lemon eucalyptus before going outside. Be sure to follow label directions.
• Wear long-sleeved shirts, long pants and insect repellent if spending time outside at dawn and dusk. Mosquitoes that spread WNV are most active at those times.
• Install door and window screens and repair any ripped or torn screens to keep mosquitoes out of your home.
• Dump and drainstanding water around your yard (WNV mosquitoes lay their eggs on standing water). Change water in pet dishes, birdbaths and wading pools at least once a week. Keep gutters free from debris.
• Contact your local mosquito and vector control agency if you are experiencing an uptick in mosquitoes where you live or work.

Health officials emphasized that the overall risk of serious illness to humans is low. People and other animals cannot spread West Nile virus.

Most individuals who are infected with the virus will not experience any illness. About one in five infected people develop a fever with other symptoms such as headache and nausea. Usually people recover completely, but some people may feel tired and sick for weeks. Extreme cases of WNV can cause vision loss, numbness, and paralysis. It can be fatal.

“It’s important to take precautions to prevent illness, especially for those who are high risk,” said Leung. “High risk groups include people over the age of 60 years, people with weakened immune systems, and those with diabetes, kidney disease or other chronic medical conditions. These groups should take extra precautions.”

Last year, 21 cases of WNV were reported in Riverside County. Individuals experiencing symptoms suggestive of WNV should contact their health provider.

For more information about Riverside County Disease Control and to view the Disease Watch dashboard, visit https://www.ruhealth.org/public-health/disease-control/disease-watch.