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Fight the Bite
West Nile virus hits the North Bay. Here's what to do about it.
By Ellen Bicheler
Ah, those balmy North Bay summer evenings. Moonlit walks. Catching the sunset at the beach. Sleeping out under the stars. And, of course, slathering any and all exposed body parts with mosquito repellant.
Life was so much simpler before the arrival of West Nile virus.
The June 22 discovery in west Ukiah of a dead crow infected with West Nile virus; the July 22 death of an infected crow in Fairfax; and the discovery in Petaluma last week of birds killed by the virus have North Bay health officials gearing up with preventative measures and advising residents to do the same.
"The best way to insure that you don't get West Nile virus is to minimize your exposure to mosquitoes," says Dr. Mark Netherda, acting deputy health officer for the Sonoma County Department of Health Services. "I advocate the 'four d's' for prevention: dump and drain all standing water; avoid being outside at dawn and dusk; dress carefully with long sleeves and long pants in potential mosquito areas; and use insect repellents that contain DEET."
West Nile virus was first identified in Uganda in 1937. Since then, a variant of the virus known as the "New York 1999 strain" has appeared in all but four U.S. states. In 2003 there were 9,862 human cases reported to the Center for Disease Control and Prevention, and a total of 264 deaths. So far this year, there have been 265 confirmed cases of the virus in the United States, resulting in six deaths.
"West Nile virus is established as a seasonal epidemic in North America that flares up in the summer and continues into the fall," according to the CDC. Mosquitoes become carriers of the virus from feeding on infected birds, then spread it to humans and other animals they subsequently bite.
Symptoms include fever, headaches, body aches, nausea and rashes, and typically occur three to 14 days after a mosquito bite. Eighty percent of those infected have no symptoms; about one in every 150 persons infected suffer serious symptoms, such as high fever, headaches, neck stiffness, stupor, tremors, convulsions, possible paralysis and even death.
Jim Wanderscheid, manager of the Marin/Sonoma Mosquito and Vector Control District says that "the biggest concerns for Sonoma County are the ornamental fish ponds, broken septic tanks, abandoned swimming pools and any potential overlooked standing water, all possible breeding areas for mosquitoes." The solution to preventing any standing water from becoming a breeding ground for mosquitoes is simple, Wanderscheid says. Simply "drain it, dip it and flip it."
His agency is part of the larger Infectious Disease Task Force for Sonoma County that includes the public health and environmental health divisions of the Sonoma County Department of Health Services, local hospitals and numerous other agencies.
The task force is working in areas like the Laguna de Santa Rosa and Santa Rosa's Spring Lake to curtail mosquito populations. They've sprayed Bacillus thuringiensis israeliensis, or Bti, a microbial insecticide that attacks mosquito larvae. Upon request, Wanderscheid says that the district will give residents Gambusia affinis, "mosquito fish" that ingest mosquitoes and are effective in water troughs, small ponds and the like.
In environmentally conscious Sonoma County, some frown upon such methods, including Sebastopol entomologist Kathy Biggs, author of Common Dragonflies of California.
"It is ludicrous to add the nonnative gambusia for mosquito control, since it eats our native mosquito predators, the larval and adult forms of the chorus frog and dragonflies," Biggs says. "In our area, stickleback would be the native fish of choice, but in ornamental ponds, I recommend the Bti dunks."
Additionally, DEET is not the insect repellent of choice for many. The Sierra Club of Canada classifies DEET as "slightly toxic" and notes that its application to human and animal skin has been linked to skin, eye and neurological problems.
There are alternatives to DEET. Patricia Dines, editor of The Next STEP newsletter (Sebastopol Toxics Education Program), is excited about a 2001 Iowa State University study that found catnip oil to be 10 times more potent than DEET. Proponents of DEET say that its prevention of mosquito bites in the West Nile virus situation far outweigh the relatively low incident of problems experienced by some users. The CDC recommends applying insect repellent containing DEET to exposed skin and clothing, but not applying it to the skin under clothes.
According to Wanderscheid, none of the dead birds found so far in Sonoma County have tested positive. Chris Canterbury, public relations manager of the Marin/Sonoma Mosquito and Vector Control District, emphasizes that they will continue their normal operations with stepped-up surveillance and an active "Fight the Bite" educational campaign.
Brock Dolman, a wildlife biologist and permaculture programs director for the Occidental Arts and Ecology Center, sees West Nile virus as an indicator of global climate change and refers to the disease as "West denial virus."
"We have created an unhealthy ecosystem, and the West Nile virus is a symptom," he says. "I'm concerned about the humans but frankly care equally about the native birds that are being infected. What defenses do they have? They can't apply DEET or avoid the dusk and dawn. The more avian insect predators we lose, the more mosquitoes we will have. Diseases such as this can become much more virulent."
Skeeter-Free, a bug repellant that features catnip oil as its active ingredient, is available from NoTox Inc. at www.insectrepel.com.
Dead birds should be reported to the California Department of Health Services West Nile virus hotline at 877.968.2473. If possible, do not handle the dead birds unless wearing heavy gloves.
For further assistance with mosquito control, contact the Marin/Sonoma Mosquito and Vector Control District at 800.231.3236. For more local WNV information, go to www.sonoma-county.org/health/ph/phpreparedness/wnv/.
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From the August 11-17, 2004 issue of the North Bay Bohemian.