First human West Nile Virus case reported

The Madera County Department of Public Health (MCDPH) is reporting its first human case of West Nile Virus (WNV) for 2022.

The individual was identified in August 2022. WNV is transmitted to people through the bite of an infected mosquito. The Madera County Mosquito & Vector Control District was notified at the time of the original diagnosis and spraying was planned in the areas where the positive tests were localized.


Most people infected with WNV have no symptoms. About 20 percent of people with WNV may experience fever, headache, body aches, joint pains, vomiting, diarrhea, or rash. Fewer than 1 percent of infections develop severe disease and people over 50 years of age or with weakened immune systems are at greater risk of experiencing severe symptoms.


“This case is a reminder of the risks from West Nile Virus-infected mosquito bites. It is important to learn and follow the recommendations to lower your risk of being bitten by mosquitoes.” stated Simon Paul, M.D., Madera County Public Health Officer:


Protect against mosquito bites and WNV by practicing the “Three Ds:”


1. DETER — Apply insect repellent containing DEET, picaridin, lemon eucalyptus or IR353 oil, 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 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 mosquitoes out. 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 flowerpots, buckets, and other water-holding containers. If you know of a swimming pool that is not being properly maintained, please contact your local mosquito control district.