Discovery of disease-carrying rodents prompts county health advisory

Confirmation that mice collected west of Beaumont tested positive for the potentially deadly hantavirus prompted Riverside County health officials today to remind residents to take precautions in places
inhabited by rodents.

According to the Department of Environmental Health, eight deer mice snared last month in the Norton Younglove Preserve, between San Timoteo Canyon Road and state Route 60, were confirmed to be carriers of hantavirus.

The pathogen can lead to a severe and potentially fatal respiratory infection in humans called hantavirus pulmonary syndrome, or HPS. County officials stopped short of issuing a health alert, noting that the find was not unusual. Five other mice netted in the same area did not test positive.

Between 2005 and 2015, roughly 10 percent of rodents collected in Riverside County were found to be hantavirus carriers, according to health officials.

“This is fairly consistent with the average for California,” said environmental health spokeswoman Dotti Merki.

Hantavirus is transmitted through rodent feces and urine. Mice do not exhibit symptoms of being sick, making identification of infected creatures difficult, according to Merki. She advised residents to avoid stirring up dust and debris when cleaning places where rodents have left droppings and to follow these recommendations:

— ventilate rodent-infested places the night before cleaning them;
— apply household disinfectants liberally in rodent nesting areas;
— use rubber gloves while cleaning;
— use a mop or sponge — not a vacuum cleaner or broom — to clean;
— double-bag dead rodents and the waste cleared out of infested areas; and
— wash hands with gloves still on, then wash again after removing them.

Warning signs of HPS include headache, fever, muscle aches, vomiting and abdominal pain. If untreated, respiratory failure can ensue.

According to the California Department of Public Health, 54 human hantavirus cases were reported in California between January 1980 and December 2014, but none were in Riverside County. One of the worst-known cases of an outbreak occurred in the Four Corners region of the desert southwest in 1993.

More than 30 people died over the course of a year.

Anyone with questions or concerns can contact the Department of Environmental Health at (951) 766-9454.