REDWOOD CITY (CBS SF) -- Public health officials warned the public Friday of the continued discovery of the deadly hantavirus in deer mice in San Mateo County, officials with the San Mateo County Mosquito & Vector Control District said.
The most recent discovery was in samples collected in May and June in the area of San Bruno Mountain and Montara.
Wild rodents carry the virus and people most frequently contract the virus when they breathe in dust contaminated with the saliva, urine and droppings of infected rodents.
Breathing the dust could occur when people are opening or cleaning previously vacant buildings.
In California, deer mice of the genus Peromyscus carry the virus. Rodents such as house mice, roof rats or Norway rats, which live near humans, do not.
Symptoms of the virus usually develop from one to eight weeks after exposure and early symptoms include fatigue, fever and muscle aches followed by a severe respiratory infection that often causes death.
No cure, treatment or vaccine exists for the people who contract the virus.
District Manager Chindi Peavey said in a statement that the virus has been found routinely in San Mateo County since 1998.
But she said, "There has never been a human case of hantavirus acquired in San Mateo County, but we do know that hantavirus circulates at low levels in deer mouse populations in our county."
Health officials want to remind residents and visitors to rural areas of the county to keep mice out of homes and structures by taking precautions such as clearing vegetation and debris from around buildings.
Do not sweep or vacuum areas that may be contaminated by deer mice to avoid breathing contaminated dust.
Campers and hikers should avoid contact with deer mice and their nests, including when using cabins and shelters.
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