LAKE COUNTY, Calif. – With Lake County now having a West Nile Virus-positive dead bird and sentinel chicken, numerous new virus-positive mosquito pools and a human case in a neighboring county, local health officials are urging county residents to take precautions to protect themselves from the disease.
Dr. Jamie Scott, Lake County Vector Control District manager and research director, said Thursday that a dead West Nile Virus-positive bird was collected 10 days earlier in Lucerne, a virus-positive sentinel chicken was found near Upper Lake and on Thursday nine new positive mosquito samples came in, bringing the season's total to 13.
Once the virus is found in chickens and other animals, the risk for human infection is considered to be increased, according to local health officials.
In its 10th year of having the presence of West Nile Virus, Lake County is seeing the season start earlier than it did in 2012, when it started in August, Scott told the Clearlake City Council at its Thursday night meeting.
West Nile Virus appearing six weeks earlier means that this will be a much longer WNV season than the county has seen before, according to Scott.
“It's not something to panic about but it is something to be aware of,” she told council members.
State health officials said that so far this year West Nile Virus has been detected in 31 of California's 58 counties.
Neighboring Mendocino County is among them, reporting this week that a state lab confirmed its first West Nile Virus-positive case in a dead bird.
Then, on Thursday the California Department of Public Health said an elderly Glenn County resident – who was hospitalized and recovering – was the first confirmed human case of West Nile Virus infection this summer in California, and that county's first case so far this year.
A Sacramento County man who died earlier this year was reported as having the disease, according to the state.
While the risk of West Nile Virus to humans – who receive it from infected mosquitoes – generally is low, according to health officials, less than 1 percent can develop a serious neurologic illness such as encephalitis or meningitis.
In addition, people 50 years of age and older have a higher chance of getting sick and are more likely to develop complications, with recent health data showing that people with diabetes and hypertension are at the greatest risk for serious West Nile Virus-related illness, officials reported.
In a joint Thursday report issued by vector control and county health officials, Scott said Lake County's West Nile Virus activity typically peaks between mid-August and mid-September. She said weather is a factor in determining how much West Nile Virus activity occurs, but even average temperatures likely would result in continued virus activity that could potentially surpass last year’s numbers.
“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,” said Lake County Health Officer Dr. Karen Tait in the joint statement with Scott.
Tait and Scott agreed that while there is no reason for alarm, personal protection against mosquito bites is the crucial step necessary to prevent humans against West Nile Virus.
“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,” said Tait.
West Nile virus symptoms of the mild form include fever, headache, tiredness, body aches and swollen lymph glands, according to Tait and Scott's report. While the illness can last only a few days, some people feel sick for several weeks.
They said 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. In a small number of cases, the infection can be fatal.
While there is no West Nile Virus vaccine for humans, vaccine is available for horses and is strongly recommended because West Nile virus also can cause serious illness or death in horses, officials said.
In her presentation to the council on Thursday night Scott noted that most people who live in Lake County love being outside, and her agency wants to make sure they can enjoy those outdoor activities.
Vector control and health officials urge the following steps to stay safe in the outdoors:
- 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.
- Dawn and dusk: Mosquitoes that carry West Nile Virus 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.
- 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.
Residents can request service, get mosquito fish, or report neglected swimming pools to the Lake County Vector Control District at 707-263-4770 or www.lcvcd.org . Just one neglected pool can produce thousands of mosquitoes every day and that may fly up to five miles away, Scott reported.
Californians are encouraged to report all dead birds and dead tree squirrels by calling toll-free 1-877-WNV-BIRD (968-2473) or by visiting www.westnile.ca.gov .
Email Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it. . Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.