Application
Tuesday, June 14, 2005
By EMILY SETZER
Index-Tribune intern
A horse was found infected with West Nile virus in Sonoma on Friday, June 10, according to county health officials.
Although most horses in the county have been vaccinated, this horse was not and developed West Nile symptoms on June 2.
"The horse came from Holland in April and was quarantined in Davis before being transported to Sonoma" said Jim Wanderschied, director of the Marin/Sonoma Mosquito and Vector Control District.
"There is a 99 percent chance that the horse was infected in Sonoma County."
Officials declined to pinpoint the location of the infected horse, but said it was in the southern part of the Valley near Highway 37. The horse seems to be recovering slowly.
This is the first confirmed West Nile infection contracted by a horse this year in Sonoma County and the second in California.
"The statistics get higher and activity appears a little bit earlier every year," said Leigh Hall, deputy county health officer.
"We're expecting a big jump this year because the virus is out there more. There are certainly more mosquitoes this year due to late rains and more standing water, but that doesn't mean they're more likely to get infected. The combination is what's really worrisome - that it's here and ready to bust and that there are lots of mosquitoes."
Signs of the virus in horses include stumbling, staggering, loss of coordination, muscle twitching, circling, and the inability to stand.
Vaccination for horses is effective and strongly encouraged and local veterinarians perform free West Nile testings.
There were 540 confirmed clinical equine cases of the virus in California in 2004 and more than 40 percent of clinically affected horses died or were euthanized.
"It's a concern," said vector control spokesman Chris Canterbury.
"Last year every county in California had West Nile activity and there were 830 human cases with 28 deaths."
Mosquitoes transmit the disease to humans and other animals after feeding on infected birds, the primarily host for the disease.
Since the first case of infected birds appeared in New York in 1999, migratory birds and mosquitoes have spread the virus across the country, creating a cycle which amplifies every year.
This year, 25 counties in California have shown activity in 106 dead birds, four mosquito pools, two chicken flocks and two horses.
Symptoms of the virus in humans range from mild flulike conditions - such as fever, headache and nausea - to a stiff neck, restlessness, stupor, delirium and convulsions.
Most cases are mild; however, fatalities can occur in extreme cases. There is no human vaccine for West Nile virus.
Vector control is checking all known mosquito breeding sites and setting adult mosquito traps in the area where the horse was stabled.
"This incident reinforces the need for residents to protect themselves against mosquito bites by eliminating standing water around their property where mosquitoes breed," said Canterbury.
"Mosquito precautions are especially important for the elderly, who are most likely to suffer serious complications from West Nile; however, all residents should take steps to reduce their risk."
The agency recommends avoiding being outside between dusk and dawn when mosquitoes are most active, wearing long-sleeved shirts and long pants when outdoors and applying insect repellant. Products containing the active ingredient DEET have been proven to be the most effective.
Screen all windows, cover septic tanks and screen roof vent pipes.
Also, report any birds that have been dead for less than 24 hours to http://westnile.ca.gov/deadbird.cfm, or (877) 968-2473.