Garden Grove, Calif. – The Orange County Mosquito and Vector Control District (OCMVCD) has detected elevated West Nile Virus (WNV) activity in the Cities of Anaheim, Orange, Huntington Beach, Westminster, and Stanton, in North Central Orange County.
OCMVCD routinely traps mosquitoes to test for the presence of mosquito-borne disease and monitor mosquito abundance. If the areas continue to have high WNV activity, OCMVCD may conduct adult mosquito control applications.
WNV occurs in a natural cycle between mosquitoes (vectors) and vertebrates (reservoirs), with humans becoming involved during WNV outbreaks. The virus also affects wildlife, with some species (crows and horses) being extremely vulnerable to infection. Human cases resulting in encephalitis and fever caused by the virus are not usually transmitted person-to-person, but largely through the bite of a competent mosquito vector.
Symptoms of WNV include flu-like symptoms associated with fever, nausea, headache, muscle aches, and occasional skin rashes. If you observe any of these symptoms, please contact your healthcare provider immediately. Severe cases of WNV can exhibit loss of coordination, delirium, coma, and death. Only 5% of severe cases result in fatality.
Although mosquito activity typically declines during October, recent rains and elevated temperatures mean WNV activity could continue into Fall.
To prevent mosquito bites, OCMVCD recommends the following:
- Wear repellent containing DEET, Picaridin, IR3535, or oil of lemon eucalyptus
- Close all unscreened doors and windows to prevent mosquitoes from entering your home or space; repair broken or damaged screens
- Wear light-colored, loose-fitting, long-sleeved shirts, and long pants while outside at dawn and dusk
- Dump and drain containers holding water at least once a week
- Clean and scrub bird baths and pet water bowls
For more information, please visit www.ocvector.org or contact Public Information Officer Brian Brannon at (714) 971-2421, ext. 7112.
Symptoms of the West Nile Virus
Here are the symptoms of West Nile virus, listed in plain text with regular bullets:
- Most people (about 80%) show no symptoms at all.
Mild symptoms (West Nile fever), which occur in about 1 in 5 people:
- Fever
- Headache
- Body aches
- Joint pain
- Vomiting or diarrhea
- Skin rash
- Fatigue or weakness that can last for weeks
Severe symptoms (less than 1% of cases), which may involve the nervous system:
- High fever
- Severe headache
- Stiff neck
- Disorientation or confusion
- Tremors or muscle jerking
- Seizures
- Partial paralysis or muscle weakness
- Coma
Severe illness can lead to long-term neurological problems or death, especially in older adults or those with weakened immune systems.
West Nile Virus Fatality Rates
Here are the most recent fatality rates for West Nile virus in the U.S. and California:
- In the United States (2023):
- 2,628 total reported cases
- 194 deaths
- Fatality rate: approximately 7.4%
- Most deaths occurred in patients with neuroinvasive disease (such as encephalitis or meningitis)
- In California (2025):
- 67 human cases reported as of October 2025
- Number of deaths not yet confirmed
- In previous years, California typically reports between 5 and 15 deaths annually
- Neuroinvasive disease occurs in about 1 in 150 infections and carries the highest risk of death
- Older adults and people with weakened immune systems are at greater risk for severe illness and fatal outcomes