West Nile virus (WNV) is a common mosquito-borne virus, first detected in California in 2003. WNV transmission to people occurs most often in summer & early fall when temperatures are warm and mosquitoes are active.
West Nile virus is influenced by many factors, including climate, the number & types of birds & mosquitoes in an area, & the level of WNV immunity in birds. West Nile virus is transmitted to humans & 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 serious neurological illnesses such as encephalitis or meningitis.
People 60 years of age and older and individuals with diabetes or hypertension have a higher chance of getting sick, and are more likely to develop complications.
Protect Yourself with the 3D’s
California Dept. of Public Health (CDPH) recommends that individuals protect against mosquito bites and WNV by practicing the 3D’s:
- DEET – Apply insect repellent containing DEET, picaridin, oil of lemon eucalyptus or IR3535 according to label instructions. Repellents keep the mosquitoes from biting you. Insect repellents should not be used on children under two months of age.
- DAWN & DUSK – Mosquitoes that transmit West Nile Virus usually bite in the early morning and evening so it is important to wear proper clothing and repellent if outside during these times. Make sure your doors and windows have tight-fitting screens to keep out mosquitoes. Repair or replace screens that have tears or holes.
- DRAIN – Mosquitoes lay their eggs on standing water. Eliminate all sources of standing water on your property by emptying flower pots, old car tires, buckets, and other containers. If you know of a swimming pool that is not being properly maintained, please contact your local mosquito and vector control agency.
For more information
- California Dept. of Public Health West Nile Virus Page
- California’s West Nile virus website includes the latest information on WNV activity in the state. Californians are encouraged to report dead birds on the website or by calling toll-free 1-877-WNV-BIRD (968-2473).