After confirming six locally acquired cases of West Nile virus (WNV) this year, County Vector Control has begun to increase its efforts to remove mosquito breeding sources while continuing to test dead birds and mosquitoes for the disease.
The victims range in age from 55 to 81, although their places of residence were not released by health officials.
Two weeks ago, 17 more dead birds found around the county, including one in Pacific Beach, tested positive for WNV.
Traps in Mission Valley and Oceanside have also captured infected mosquitoes.
“West Nile virus, like the seasonal flu, is here to stay, for the foreseeable future,” said Wilma Wooten, M.D., M.P.H., San Diego County Public Health Officer. “While there is no WNV vaccine at this time, the public can take many steps to guard against mosquitoes, which spread the disease.”
The first 2007 human case was reported earlier this month after an 86-year-old East County man was diagnosed with meningoencephalitis in late August.
An 85-year-old Los Angeles man became ill due to WNV after visiting San Diego County, but county health officials believe the disease was contracted elsewhere.
A third probable case is pending confirmation from the California Department of Health testing laboratories.
“West Nile virus is here to stay, so we are cautioning the public to stay alert,” said Mark Webb of the San Diego County Department of Environmental Health.
Most prevalent from August to October and primarily a bird disease, West Nile virus is transmitted among birds and mosquitoes. Then when an infected mosquito bites a human, the virus is passed to the person.
Mark Webb of the San Diego County Department of Environmental Health said the bird found in Pacific Beach was an American crow.
“We are still collecting birds every day and testing them,” he said.
So far, San Diego County has identified 75 infected birds this year, as compared to 19 birds testing positive in 2006.
American crows and western scrub jays are the most commonly reported bird deaths from West Nile in California.
The recent hot and humid weather conditions intensify concerns, however, and the recent heat increases chances for mosquito breeding.
People in any areas where the West Nile virus is identified risk exposure, the elderly or chronically ill persons are most vulnerable.
According to the Centers for Disease Control, about 80 percent of people bitten by an infected mosquito experience no symptoms. The remaining 20 percent may develop fevers, headache, body aches, nausea, vomiting, swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms may last from a few days to several weeks; there is no evidence that West Nile can be transmitted from person to person. Only about one in 150 people infected with the virus develop serious illness.
“It’s important for the public to take precautions against West Nile Virus,” said Wilma Wooten, M.D., and San Diego County public health officer.
“Mosquito bites are most common from dusk to dawn,” Dr. Wooten said.
“Long-sleeved, light-colored clothing and long pants protect the skin, and insect repellents containing DEET, Picaridin, and Oil of Lemon Eucalyptus work best,” said Wooten.
“These products have been extensively studied for effectiveness and safety,” Wooten said, “and the recommended insect repellants are available at grocery stores or in the sporting goods sections of other stores.”
Eliminating standing water sources, like plant saucers, spare tires, birdbaths, empty buckets and unused flower pots helps control mosquito breeding. Neglected ponds or pools should be reported to county authorities.