Officials Urge Caution After Hantavirus Found in Mice

After finding deadly hantavirus for the first time in Ventura County in two deer mice trapped near Wood Ranch, scientists Wednesday said this: Don’t panic.

The discovery comes as part of a statewide campaign launched three years ago after a hantavirus outbreak in New Mexico. Since then, California health workers have trapped and tested nearly 5,000 animals in a search for those carrying the virus.

Biologists have found hantavirus predominantly in deer mice in the counties of Los Angeles, Orange, Santa Barbara, Kern--and now Ventura.

Health officers laid 50 traps in Simi Valley, catching, drugging and killing 21 deer mice.

Blood samples showed that two mice carried traces of hantavirus, said Robert Gallagher, vector control officer for the Ventura County Department of Environmental Health.

“We put out this [information] not to overtly alarm the public,” he said. “We just wanted to inform them that when they enter into certain areas, they need to take simple precautions to avoid exposure.”

People who inhale dust containing the dried urine or droppings of deer mice risk catching hantavirus.

Those infected suffer quickly worsening flu-like symptoms, such as chills, muscle ache, nausea, vomiting and shortness of breath.

Treated soon enough with oxygen and antiviral drugs, victims can survive. Yet more than half of those who catch the virus die as their lungs fill up with fluid.

While hantavirus is not contagious from person to person, there is no known cure.

“There isn’t any reason to panic,” said Dick Davis, a biologist with the California Department of Health. “It’s just a matter of using good sense and some degree of caution,” such as wearing a dust mask, rubber gloves and using disinfectant when cleaning up after mice.

“Hantavirus,” he added, “has probably been around for a very long time.”

A strain of hantavirus was first diagnosed in the 1950s in the Hantan region of Korea, as 3,000 U.S. servicemen fighting the Korean War came down with something then called hemorrhagic fever. Of those, 190 died.

Hantavirus again caught the public eye in 1993, when the New Mexico outbreak sickened and killed dozens of people.

In California, there have been 13 confirmed cases of hantavirus in people. Eight of those died.

Hantavirus, Gallagher said, is perhaps more difficult to catch than bubonic plague, a bacterial infection that is carried by fleas and curable with antibiotics. But hantavirus kills about half the people it infects, Davis said.

“With that kind of fatality rate, it’s not that far behind Ebola and some of those others,” he said. “So we take it very seriously.”

People should wear dust masks and rubber gloves when cleaning summer cabins, shacks or other buildings that have been infested by deer mice, he said.

Exposure is no guarantee of infection. Davis said a survey of 3,000 public health officers across the nation found hantavirus antibodies in only two people.

“Which probably points out, again, that this is an extremely hard disease to catch,” Davis said.