The recent discovery in San Jose and Campbell of mosquitoes infected with the potentially deadly West Nile virus has prompted officials to launch a ground-fogging offensive on Thursday, with most of the action centered around Fruitdale and Leigh avenues.
In one of the most active seasons for the virus in recent years, the infected adult mosquitoes were collected Saturday from three zip codes in the two cities -- 95125, 95126 and 95128. And the Santa Clara County Vector Control District decided to act quickly in an effort to prevent human cases of the dangerous virus.
"The first two WNV human cases in California this year were confirmed last week," said Acting District Manager Russ Parman. "There is no cure for the West Nile Virus disease, and it can have long-term health consequences, so we need to do everything we can to minimize the spread of human cases."
The risks posed by the West Nile virus, which is transmitted by mosquito bites, range from mild to severe flu-like symptoms, including headaches and rashes, but in the most dire cases it can lead to death. Parman said even the milder form of West Nile fever "is no walk in the park; you're off work an average of 16 days and you can have problems that last for years.''
He said the people most at risk of contracting the fever or virus are the elderly and people who have compromised immune systems, and he recommends those people try to stay indoors as much as possible to avoid getting bitten by mosquitoes.
The fogging area is generally bordered by West San Carlos Street on the north; Lincoln Avenue on the east; Willow Street, Los Gatos Creek trail, and Southwest Expressway on the south; and Highway 17 on the west. A live map can be viewed at http://bit.ly/1pRRaTU.
The fogging should last several hours and authorities say the chemicals used to kill the mosquitoes pose no danger to animals or humans. Parman said a truck-mounted unit traveling 15 miles-per-hour will spray the atomized liquid. Applying only three tablespoons per acre, the dosage is low enough so that only insects a third of an inch or smaller would be killed.
"The mosquitoes have very tiny bodies,'' he said, "so it doesn't take a lot of the microdroplets to stick to the mosquito and knock it down. We usually get a 50-80 percent knockdown rate once the spray leaves the truck, depending on the wind.''
Since the arrival of West Nile virus to California in 2003, 4005 people across the State have contracted the disease; 145 of those cases were fatal.
"Residents can play a strategic role in preventing the spread of West Nile Virus," said Parham. "It is important to remain vigilant by taking practical steps to eliminate mosquito breeding areas."
Contact Patrick May at 408-920-5689 or follow him at Twitter.com/patmaymerc
If you need to go outside in an area where mosquitoes are active:
For free assistance on mosquito control, WNV, or other vectors, residents can contact the District office by calling (408) 918-4770 or fill out a service request online at SCCvector.org.
Source: Santa Clara County Vector Control District