The Los Angeles County Department of Public Health has confirmed the first human cases of West Nile virus (WNV) infection in Los Angeles County for the 2014 season. A female, 60s, from the San Fernando Valley with no prior medical history was hospitalized for WNV disease mid-July. The patient is in the hospital and recovering. The second case, a WNV-positive asymptomatic blood donor, male 20s, was reported in late July. He resides in the southern part of the county and remains healthy.

Culex mosquito
Culex quinquefasciatus

“All residents should take the proper precautions to avoid and protect against mosquitoes, as that is the primary way the disease is transmitted. Mosquitoes obtain the virus by feeding on infected wild birds,” said Jonathan E. Fielding, MD, MPH, Director of Public Health and Health Officer. “West Nile can appear anywhere in Los Angeles County, or around the state, and we are urging people to take precautions, such as getting rid of pools of stagnant water around their homes, and using a repellent containing DEET when outdoors in mosquito prone areas, especially around dawn or dusk.”

As of Tuesday, there has been 35 human WNV cases reported in California.

West Nile virus is transmitted to humans and animals by the bite of an infected mosquito. The risk of serious illness to most people is low. However, some individuals – less than one percent – can develop a serious neurologic illness such as encephalitis or meningitis. People 50 years of age and older have a higher chance of getting sick and are more likely to develop complications. Recent data also indicate that those with diabetes and/or hypertension are at greatest risk for serious illness.