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West Nile Virus Alert

Staying indoors during early morning and evening hours, keeping window screens in good repair, wearing protective clothing and use of insect repellents according to package instructions will help reduce your risk of catching the infection.

LAKEPORT, CA. Following the mid-June detection of West Nile Virus (WNV) in mosquito samples – the earliest appearance of WNV Lake County has experienced – the virus has now been detected in a “sentinel chicken.” This is another sign that Lake County may be in for a long WNV season.

As part of the routine surveillance system used to monitor WNV activity, designated chicken flocks are tested for the virus in addition to mosquitoes, dead birds, and tree squirrels. The virus generally makes its first appearance in mosquitoes. Once it is found in chickens and other animals, the risk for human infection is considered to be increased.

According to Lake County Health Officer, Dr. Karen Tait, “This is the time to be particularly careful to avoid mosquito bites and, given the early appearance of the virus in Lake County, it will be important to maintain those precautions for quite a while.”

Lake County Vector Control District (LCVCD) Manager and Research Director Jamesina J. Scott, Ph.D. notes that “Last year there was a lot of West Nile virus activity in Lake County, but it didn’t start until August. This year it started 6 weeks earlier, which means that this will be a much longer WNV season than we have seen before.” According to Dr. Scott, WNV activity in Lake County typically peaks between mid-August and mid-September. Weather is a factor in determining how much WNV activity occurs, but even average temperatures would likely result in continued WNV activity that could potentially surpass last year’s numbers.

Drs. Tait and Scott agree that while there is no reason for alarm, personal protection against mosquito bites is the crucial step necessary to prevent human cases of WNV.

“Staying indoors during early morning and evening hours, keeping window screens in good repair, wearing protective clothing and use of insect repellents according to package instructions will help reduce your risk of catching the infection,” according to Dr. Karen Tait, Lake County Health Officer.

LCVCD is a public health agency that protects Lake County residents and visitors from mosquitoes and other vectors and vector-borne diseases. Residents can request service, get mosquito fish, or report neglected swimming pools to the District at 263-4770 or Just one neglected pool can produce thousands of mosquitoes every day and that may fly up to five miles away.

The public can also report dead birds or tree squirrels to 1-877-WNV-BIRD (1-877-968-2473) or online at California Department of Public Health’s West Nile virus website at

One fatal human case of West Nile virus infection was reported in California earlier this year, serving as a reminder that taking precautions is important to preventing this sometimes serious and even deadly infection. The first case of the summer was just reported in Glenn County.

West Nile virus symptoms of the mild form include fever, headache, tiredness, body aches, and swollen lymph glands. While the illness can last only a few days, some people feel sick for several weeks.

Less than one percent of individuals (about 1 in 150 people) infected with West Nile virus will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent. West Nile virus infection can be fatal. People over age 50 and diabetics appear to be at most risk for the more severe forms of disease. There is no vaccine for humans.

A vaccine is available for horses and is strongly recommended because West Nile virus can also cause serious illness or death in horses.

Recommendations for everyone include:

1. DRAIN - Mosquitoes lay their eggs on standing water. Eliminate all sources of standing water on your property, including buckets, old car tires, pet bowls, and unused wading pools. If you have a pond or livestock watering trough, contact the Lake County Vector Control District for mosquito fish.

2. DAWN AND DUSK - Mosquitoes that carry WNV bite in the early morning and evening. When possible, avoid being outside at these times. If you are outside when mosquitoes are active, use repellent and wear long-sleeved clothing that reduces the risk of skin exposure to mosquito bites during this time.

3. DEFEND - Use an EPA-registered insect repellent with DEET, picaridin, oil of lemon eucalyptus, or IR3535 and apply it according to label instructions. Repellents keep mosquitoes from biting. Make sure your doors and windows have tight-fitting screens to keep out mosquitoes. Repair or replace screens with tears or holes.

For additional information on West Nile virus, visit,,, and