News Details

West Nile virus detected in Solano County

August 16, 2017

SOLANO COUNTY – The Solano County Department of Health and Social Services, Public Health division and the Solano County Mosquito Abatement District (SCMAD) have confirmed that three mosquito samples collected from the Suisun Marsh and one from a sparrow found in northern Vallejo have tested positive for West Nile virus (WNV). The samples were collected earlier this month.

As of August 11, 2017, the California Department of Public Health (CDPH) reports that WNV activity has been detected in 28 other counties. To date there have been 22 reported human cases of WNV infection throughout the state.

"These are the first confirmed indications of local West Nile virus activity this year," said Dr. Michael Stacey, MD, MPH, Deputy Health Officer for the County. "So far, we have not received any reported cases of human infection from West Nile virus. The findings serve as a reminder to our community that risks can be greatly reduced by taking simple precautions."

West Nile virus is transmitted to humans and animals through the bite of an infected mosquito.  Mosquitoes become infected when they feed on infected birds.  To avoid getting diseases transmitted by mosquitoes, like West Nile virus and Zika virus, County officials recommend the following:

Dawn and dusk
Mosquitoes are most active in the early morning and evening.  Residents should avoid being outside at these times.  If you are outdoors, wear a long-sleeved shirt and long pants and use insect repellent.

Drain standing water
Mosquitoes lay their eggs on standing water.  Residents should eliminate all sources of standing water on their property and drain empty flower pots, buckets, barrels, old car tires, rain gutters and pet bowls.  If you have an ornamental pond, contact the Solano County Mosquito Abatement District at (707) 437-1116 for a free mosquito fish.

DEET and other repellents
Insect repellents help keep mosquitoes from biting.  Apply an EPA-registered insect repellent containing DEET, picaridin, oil of lemon eucalyptus, IR3535 or para-menthane-diol products per the manufacturer's instructions.

Doors and windows
Residents should ensure that their doors and windows have tight-fitting screens to keep mosquitoes out.  Repair or replace screens with tears or holes.

Most people (about 4 in 5) infected with the West Nile virus will not develop any symptoms.  About 1 in 5 will develop mild symptoms, including fever, headache, body aches, nausea, vomiting and swollen lymph glands.  However, about 1 percent (about 1 in 150) of persons with WNV infections will develop severe neurological disease.  In rare cases, WNV infection can be fatal.

Anyone can be infected with West Nile virus, but people who are 60 years old and older and those with certain medical conditions, like cancer, diabetes, hypertension, kidney disease and people who have received organ transplants, are at greater risk of developing severe illness and complications.

The SCMAD staff is conducting surveillance activities in the affected area to find the sources of the samples and apply appropriate control measures where mosquitoes of the same infected species are present.

“We work vigilantly to control the mosquito populations throughout the County and use all the tools that we have; however, I would like to emphasize the availability of effective mosquito repellents and encourage residents to use them regularly,” says Richard Snyder, Solano County Mosquito Abatement District Manager.  “I also urge residents to join us in our prevention and control efforts by making sure that they don't have any standing water on their property and to report any unmaintained swimming pools and stagnant water by calling us at 707-437-1116.”

Residents are encouraged to report dead birds and squirrels online at or by calling 1-877-WNV-BIRD (1-877-968-2473).