West Nile Virus activity begins in Solano County

May 29, 2015

SOLANO COUNTY – Solano County Mosquito Abatement District (SCMAD) and Solano County Department of Health and Social Services (SCDHSS) officials confirmed on Thursday that one American Crow found in the City of Vallejo tested positive for West Nile virus (WNV).

"This is the first evidence that we have of local WNV activity in Solano County this year," said Dr. Michael Stacey, MD, MPH, Chief Medical Officer and Deputy Health Officer for the County.  “We have not had any reported cases of WNV infection in humans so far this year."

As of May 22, 2015, the California Department of Public Health (CDPH) reports that WNV activity has been detected in nine other counties; however, no human cases have been reported in California to date.

According to CDPH, there were 801 reported human cases of WNV infection in 2014; the second-highest number of human cases since the virus was first identified in California in 2003.  The majority of birds tested in 2014 were positive for WNV, the highest ever detected in the State.

According to CDPH, the ongoing drought has contributed to the high WNV activity by creating more limited sources of water for birds and mosquitoes, allowing them to come into closer contact with each other.

It is difficult to predict if the level of WNV activity in 2015 will stay the same as or be lower than in 2014 because there are many factors that contribute to the level of activity, including climate, the number and types of birds and mosquitoes in an area and the level of immunity to WNV in birds.

“The ongoing drought may contribute to a continued elevation of West Nile activity this year”, said Jon Blegen, Solano County Mosquito Abatement District Manager.

West Nile virus is transmitted to human and animals through the bite of an infected mosquito.  Mosquitoes become infected when they feed on infected birds.

“This serves as a reminder to the community that we need to follow these simple precautions to ensure that we protect ourselves against mosquito bites and reduce our risk of infection”, said Dr. Stacey.

To avoid being bitten by mosquitoes, 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 long-sleeved shirt and long pants and use insect repellent.

- Drain: 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 (707) 437-1116 for a free mosquito fish.

- DEET: Insect repellents keep mosquitoes from biting.  Apply an EPA-registered insect repellent containing DEET, picaradin, oil of lemon eucalyptus or IR3535 according to 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 infected with the 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, less than 1 percent (about 1 in 150) of persons with WNV infections will develop severe neurological disease.  In very rare occasions, WNV can be fatal.

Anyone can be infected with WNV, but people who are 50 years old and over and those with diabetes or hypertension are at higher risk of developing severe illness and complications.

“We use all the tools that we have in order to control the mosquito populations throughout the County; however, I would like to emphasize the availability of effective mosquito repellents and encourage residents to use them on a regular basis,” Blegen said.  “I also would like to ask residents to help with 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 707-437-1116.”

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