Hantavirus discovered In North County


County urges residents to be careful when finding, cleaning rodent infestations

Two deer mice trapped last week in Carlsbad have tested positive for the potentially-deadly hantavirus.

A combination of 53 mice and voles tested positive for hantavirus in the county in 2011, more than double the 21 that tested positive in 2010. Hantavirus can cause hantavirus pulmonary syndrome (HPS), which begins with flu-like symptoms but can escalate into severe breathing difficulties and even death.

“This record high number of positive rodents is most likely due to two years of ample rain,” said Jack Miller, director of the County Department of Environmental Health. “The rain increases vegetation which provides plenty of food and shelter for the rodents to breed and multiply.”

Infected mice and voles rarely pose a danger to people when they are in the wild. But when they infest homes and garages, people can contract hantavirus by inhaling dust particles from rodent droppings and nesting materials that contain the virus. There is no treatment, vaccine or cure for hantavirus infections, which are deadly in 36 percent of cases, according to the National Centers for Disease Control and Prevention.

The best way for people to prevent themselves from being exposed to the disease is to keep mice out of houses, garages and sheds by sealing holes larger than the size of a dime, County officials said.

For more information contact the County Department of Environmental Health at (858) 694-2888 or visit

and view: “Hantavirus: The Airborne Menace.”

How to Avoid Exposure to Hantavirus:

· Avoid rodent infested areas. Do not stir up dust or materials that may be contaminated with feces and urine.

· Immediately eliminate rodent infestations if you have them.

· Clean up rodent droppings and urine using the wet cleaning method described below.

· Use “Wet-Cleaning” Methods To Prevent Inhaling The Virus:


· Ventilate affected area by opening doors and windows for at least 30 minutes.

· Use rubber gloves. Spray a 10 percent bleach solution (2 tablespoons bleach to 1 cup of water), or other full strength disinfectant onto dead rodents, rodent droppings, nests, contaminated traps, and surrounding areas and let the disinfectant stand for at least 15 minutes before cleaning. Clean with a sponge or a mop.

· Place disinfected rodents and debris into two plastic bags, seal them and discard in the trash.

· Wash gloves in a bleach solution, then soap and water, and dispose of them using the same double-bag method. Thoroughly wash your bare hands with soap and water.

--Staff Reports