Cactus Mice Test Positive for Hantavirus, First Local Detection of 2020

cactus mouse Image Credit: shutterstock

Two cactus mice collected separately in routine monitoring in Santee and Valley Center have tested positive for hantavirus, marking the first appearance in San Diego County in 2020 of the potentially deadly virus.

County officials said people should never sweep up or vacuum, but use “wet cleaning” methods instead, to clean up rodent droppings or signs of rodent infestation if they find them in their living spaces — homes, garages, sheds, cabins and outbuildings.

Infected rodents shed hantavirus in their urine, feces and saliva. If people stir that dry matter into the air by sweeping or vacuuming, they can inhale the virus and get sick.

Hantavirus is common in San Diego County. In 2019, 42 rodents collected in routine trapping tested positive for hantavirus. There is no cure or vaccine for hantavirus and it can cause deadly infections in people.

However, people are unlikely to be exposed to the virus because its main carriers — wild rodents and particularly wild mice — prefer to live away from people.

Still, County officials said people should be careful to use wet cleaning methods if they find rodent droppings or evidence that wild rodents have gotten into homes, garages, sheds, cabins and other living spaces, and must clean.

Here are tips for people to prevent being exposed to wild rodents and hantavirus, and instructions for how to use wet-cleaning methods.

Avoid Exposure to Hantavirus

  • Seal up all external holes in homes, garages and sheds larger than a dime to keep rodents from getting in.
  • Eliminate rodent infestations immediately.
  • Avoid rodent-infested areas and do not stir up dust or materials that may be contaminated with rodent droppings and urine.
  • Clean up rodent droppings and urine using the wet cleaning method described below.

Use “Wet-cleaning” Methods to Prevent Inhaling the Virus

  • Do not sweep or vacuum infested areas.
  • Ventilate affected area by opening doors and windows for at least 30 minutes.
  • Use rubber gloves. Spray a 10 percent bleach solution or other disinfectants 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 that has been soaked in disinfectant.
  • 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 hands with soap and water.

For more information, contact the County Department of Environmental Health (DEH) at (858) 694-2888 or visit the DEH hantavirus web page.

Gig Conaughton is a communications specialist with the County of San Diego Communications Office. Contact