Hantavirus Found in Six More Rodents : Disease: Five of the animals testing positive are of a second variety of mice. Officials say no public health threat is posed.
SANTA ANA — Six more rodents trapped in South County have tested positive for the hantavirus, perhaps the same strain responsible for 40 deaths nationwide, county health officials said Thursday.
That brings to 11 the number of rodents trapped in the county since last August that showed exposure to the virus.
Most significantly, five of the latest six rodents to test positive were harvest mice, whereas all the other mice testing positive have been deer mice, the rodent variety believed to be the chief “reservoir†for the virus.
County health officials, however, stressed that they believe the latest finding poses no health threat to county residents.
Jim Webb of the Orange County Vector Control District said the district staff only a few weeks ago decided to expand its hantavirus surveillance program beyond deer mice to include harvest mice. He said that when one harvest mouse was found positive, investigators decided to test the carcasses of others that had been previously trapped.
Webb said preliminary blood tests of five harvest mice show that they were probably exposed to a hantavirus similar to the kind that surfaced in May of last year, when victims contracted the airborne disease from exposure to blowing dust contaminated with mice droppings in the Four Corners area of Colorado, Utah, Arizona and New Mexico.
One of the harvest mice testing positive for hantavirus was trapped in August, 1992, in a rural area near San Clemente, and three were trapped between July, 1993, and last month in Crystal Cove State Park. In addition, a deer mouse with positive antibodies was trapped in December, 1993, in the San Joaquin Hills.
Results of further laboratory tests will be required to precisely determine the strain of hantavirus to which all six trapped mice were exposed and how long their urine and feces might have carried the virus.
Symptoms of the disease, which so far has infected five people in California, killing four, include breathing problems, nausea and fever.
Orange County health officials said that so far there have been no reported cases of hantavirus in the county and thus they do not believe the public health risk in the area is very great. They say it is possible that mice have long been infected with the disease but have not passed it to humans, partly because the mice live in rural areas.
“While many questions remain concerning the hantavirus infection, there is no evidence at present to suggest a significant health hazard for Orange County residents,†Health Care Agency officials said in a statement.
“There is not an imminent high level of danger,†said Dr. Hildy Meyers, a county epidemiologist. “We are just reminding people there is a possibility the hantavirus is here and to remember the precautions.â€
County officials offered these tips as “prudent steps†in avoiding the disease:
* Prevent rodents from entering buildings by covering up access holes.
* Clean up rodent droppings and dead rodents by soaking them in household disinfectant or a 1:10 dilution of bleach and using waterproof gloves to place them in double plastic bags for disposal.
* When hiking or camping, avoid contact with rodents and their burrows and droppings, and store food and garbage in rodent-proof containers.
* Take special precaution when entering or cleaning buildings in rural areas that may be rodent infested.
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