July 11, 2021 - SACRAMENTO – The California Department of Public Health (CDPH) announced last Friday the first confirmed death in California due to West Nile virus (WNV). The death occurred in San Luis Obispo County.

"West Nile virus activity in the state is increasing, so I urge Californians to take every possible precaution to protect against mosquito bites," said Dr. Tomás J. Aragón, Director of the California Department of Public Health and State Public Health Officer.

West Nile virus is transmitted to humans and animals by the bite of an infected mosquito. As of July 9, WNV has been detected in 45 dead birds from 6 counties and 177 mosquito samples from 13 counties. Hot temperatures this month are contributing to increasing numbers of mosquitoes and the increased risk of virus transmission to humans. So far this season, activity is within expected levels. The risk of disease due to WNV usually increases at this time of year and is highest throughout the summer and early fall.

West Nile virus is influenced by many factors, including climate, the number and types of birds and mosquitoes in an area, and the level of WNV immunity in birds. The risk of serious illness to most people is low. However, some individuals – less than one percent – can develop serious neurologic illnesses such as encephalitis or meningitis.

People 50 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 from WNV infection.

CDPH recommends that individuals protect against mosquito bites and WNV by practicing the "Three Ds":

1. DEET – Apply insect repellent containing DEET, picaradin, 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.

2. DAWN AND DUSK – Mosquitoes that transmit WNV 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 that your doors and windows have tight-fitting screens to keep out mosquitoes. Repair or replace screens that have tears or holes.

3. 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.

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).
Source: CDPH