Northern California is going to be the epicenter of West Nile Virus this year, and Kalei Lau, Danville representative on the county mosquito control board, is urging residents to clean up standing water in their back yards.
Lau made a presentation to the Danville Town Council recently, reporting that the Contra Costa County Mosquito and Vector Control District is tripling its education staff and doubling its field staff.
“One thing is to have people be mindful of backyard reservoirs of water,” said Lau. “It’s a simple thing a citizen in Danville or anywhere in Contra Costa County can take ownership of.”
This includes pots around plants, bird baths, boat covers, indentations in yards where water may puddle and any place else that water may stand for five days or more, making it a potential breeding ground for mosquitoes. It takes five days for a mosquito to go through its entire life cycle, from egg to biting adult.
“Back yards are the No. 1 source of breeding in Contra Costa County,” said Deborah Bass, public information officer for the district. She said the biggest misconception about mosquito breeding is that it takes place in agricultural water but nearly 80 years of monitoring of mosquitoes has taught the district otherwise.
“Mosquitoes can breed in a couple of tablespoons of water,” she said, adding that 800,000 mosquitoes can be bred in one tire in a side yard. “I can’t emphasize enough about checking yards after the recent rains.”
Fountains can be a source but are OK if they are flowing, said Bass, but she suggested using a “mosquito dunk,” a natural pesticide that can be purchased at any garden center. “It is not harmful to fish or birds and is very specific to mosquitoes,” she said. She suggested flushing out birdbaths one a week.
The County Mosquito and Vector Control District also provides free mosquitofish, which can eat up to 500 mosquito larvae every day. These are available between 8 a.m. and 4:30 p.m. at the district office, 155 Mason Circle in Concord; telephone 685-9301.
Bass urged people to report dead birds, by calling 1-877-WNV-BIRD (968-2473). She also stressed the importance of vaccinating horses but said cats and dogs do not seem susceptible to the virus.
West Nile Virus, which first appeared in the Eastern United States in 1999, is transmitted to humans and animals through the bite of an infected mosquito and cannot be spread person to person. Mosquitoes become infected with the virus when they feed on infected birds.
“It is estimated that one in five people bitten by an infected mosquito become ill,” according to district reports. “People who do become ill may experience symptoms like fever, headache and body ache. Less than 1 percent of infected individuals require hospitalization.” For information concerning West Nile Virus testing, call the Health Services Department at (888) 959-9911.
A total of 830 West Nile Virus infections were reported from 23 counties in California in 2004, with 28 human fatalities. There have been no reports of the virus in humans in 2005, although it has been detected in 21 California counties. In 2004, 19 birds were found in Contra Costa County with West Nile Virus, including a Western Scrub Jay found in September in Alamo near Stone Valley and Roundhill roads.
“To date (this year), there have been three positive birds with West Nile Virus in the county,” Bass said, “but no horses, no chickens and no humans.”
“This is the second years we’ve had it and the second year is always the worst year,” she added. “Northern California is going to be the epicenter for West Nile Virus this year.”
