The first days of spring mean that it’s time for baseball and
the return of West Nile virus, and local pest experts warn that
this year’s mosquito season is going to be a long one.
Morgan Hill – They’re back.
The first days of spring mean that it’s time for baseball and the return of West Nile virus, and local pest experts warn that this year’s mosquito season is going to be a long one.
“We’re looking at it probably being worse,” said Kriss Costa, spokeswoman for the Santa Clara County Vector Control District. “This will be our second real serious year.”
Last year, five county residents contracted West Nile, along with one horse and at least 144 birds, the most since the disease reached California in 2002.
All five humans survived, but the virus’s history and the region’s wet spring augur a dangerous year for county residents.
Traditionally, a moderate infestation is followed by an outbreak. In another ominous sign, four of the eight California birds to test positive for the virus this year are in Santa Clara County.
“With all this rain and the wet weather, we already have mosquitoes developing and adults flying,” Costa said. “There are eight positive birds in the state and half of them are here.”
The good news is that the vector control district has more weapons at its disposal this year. A parcel tax passed last year by county property owners raises about $4 million annually for the district, more than doubling the agency’s budget.
That money will pay for 10 new staff members and expand the district’s monitoring and inspection capabilities. Seasonal workers will go so far as to check out lingering curbside puddles.
Last year, vector control sprayed mosquito-killing chemicals in South San Jose, but its area of concern is already wider in 2006. The four positive birds were found in Saratoga and Santa Clara.
Right now South County is pretty quiet and I’m hoping it stays that way,” Costa said. “We didn’t have a really hot summer last year, but if we do this year, with a lot of hot days and evenings that don’t drop below 60, we could have some problems. … If the public sees places that continually hold water we need them to call us and let us know. We’re going to do more surveillance and more mosquito trapping.”
The virus was discovered in the West Nile region of Uganda in 1937.
It was found in New York in 1999 and came to California in 2002. In the last two years, according to the University of California, the state’s death and infection rates led the nation.
Last year, the worst West Nile outbreaks were in the Central Valley and in Sacramento County, which registered a record 175 human cases.
Statewide, 929 people in 40 counties contracted the virus and there were 18 fatalities. In 2004, there were 830 confirmed cases in 23 counties, with 28 deaths.
State researchers expect that this year’s mosquito population will be unusually high as a result of heavy snowpacks in the Sierra Nevada and a wet winter in the Central Valley.
“These conditions are like their wake-up call,” said Gregory Lanzaro, an entomology professor at UC Davis. “The mosquitoes that were infected with WNV before they went into their semi-hibernation still have the virus. They’re loaded and ready to go.”
Researchers at the centers for Disease Control and Prevention estimate that one in five people bitten by an infected mosquito will become ill, though fewer than 1 percent of cases require hospitalization.
People older than 50 and those with immune system disorders are most susceptible to the virus.
Symptoms of WNV
Symptoms of the virus are similar to flu symptoms.
- They include:severe headache, fever, fatigue
-
If you spot a dead or struggling bird that does not appear to have any injuries call the state hotline at 877-968-2473.
-
If you have any questions or are interested in mosquito-eating fish, call Santa Clara County Vector Control at 792-5010.
The Seven D’s of West
Nile Virus
- Dawn and Dusk: avoid spending time outside when mosquitoes are most active
-
Drain: empty standing water on your property
-
Dress: wear shoes, socks, long pants and long sleeves when mosquitoes are most active
-
Defend: use effective repellents such as DEET, Picaridin or oil of lemon eucalyptus
-
Door: ensure door and window screens are tight-fitting
-
DEET: it’s for adults only and should be used on clothing, not skin
-
District: contact the Santa Clara County Vector Control District at 792-5010
Source, University of California, Davis
