Los Angeles–The Los Angeles County Department of Public Health (Public Health) has identified the first case of human West Nile virus (WNV) infection in Los Angeles County for the 2021 season (excluding Long Beach and Pasadena as cases identified in those cities are reported by their local health departments). A resident of the South Bay area was hospitalized with WNV fever in late July and is recovering.
West Nile virus is spread by the bite of an infected mosquito. Symptoms may include fever, headache, nausea, body aches, and a mild skin rash. WNV can affect the nervous system and result in meningitis, encephalitis, paralysis and even death. Adults over the age of 50 years old and people with chronic health problems are at higher risk of severe illness. While not all mosquitoes carry this virus, the type of mosquito that spreads this virus is found throughout Los Angeles County.
Public Health recommends the following actions to reduce the risk of West Nile virus infection:
- Avoid mosquito-infested areas at dawn and dusk.
- Use insect repellant. Use Environmental Protection Agency (EPA)-registered repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. When used as directed, EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women. Find the right insect repellent for you by using EPA’s search tool.
- Cover up. Consider wearing long-sleeved shirts and long pants when you are outdoors, particularly at these times and in areas where more mosquitoes are present.
- Take steps to control mosquitoes indoors and outdoors.
- Use screens on windows and doors. Check for and repair holes in screens to keep mosquitoes outdoors.
- Stop mosquitoes from laying eggs in or near water. Once a week, empty and scrub, turn over, cover, or throw out items that hold water, such as tires, buckets, planters, toys, pet bowls, flowerpot saucers, rain barrels, or other containers. These are where mosquitoes lay eggs.
- Empty and wash birdbaths and wading pools weekly.
- Clean and chlorinate swimming pools; drain any water collecting on pool covers.
- Stock garden ponds with mosquitofish (Gambusia affinis), goldfish, Koi or other mosquito-eating fish. These feed on mosquito eggs and larvae.
Public Health continues to document human cases of WNV every year in LA County, at an average of 118 cases per year during the previous 5 years. However, the total number of people infected with WNV each year in LA County is much higher as most infected persons do not experience any illness or only mild illness. These cases are neither reported nor recognized as WNV. About three-quarters of reported cases have had severe disease and approximately 9% of patients with severe WNV die from complications.