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First Detection of Hantavirus in 2025

 

Last updated 1/14/2025 at 8:01am



A deer mouse collected at the beginning of January, in Cuyamaca Rancho State Park, has tested positive for the potentially deadly hantavirus.

Finding hantavirus in wild rodents is not uncommon in San Diego County, there were a total of 25 cases in 2024 and are the main carriers of hantavirus. However, people rarely come into direct contact with infected animals because wild rodents naturally avoid humans. Mice that commonly live with humans are house mice and do not carry hantavirus.

While exposure to hantavirus is rare, people should be careful around wild rodents as there is no cure or vaccine for hantavirus. Hantavirus is a rare but deadly virus that is spread by infected rodents. The infection is spread by inhaling particles from rodent droppings. The disease does not affect the mice themselves but can make people seriously ill. About 30 – 40% of people who contract the virus die from it.

Excluding rodents from homes, cabins, sheds, and other structures, airing out unused structures before entering, and using a wet cleaning method and other safe cleaning practices (described below) can reduce your exposure to hantavirus.

The Vector Control Program routinely collects blood samples from wild mice to test for hantavirus. If positive results are found, the public is notified of appropriate precautions to take to lower risk of exposure.

Symptoms of hantavirus usually develop between 1 to 8 weeks after exposure and include:

Severe muscle aches

Chills, fever or fatigue

Headache or dizziness

Nausea, vomiting or stomach pain

Difficulty breathing

Hantavirus does not spread from person to person.

Contact your doctor immediately if you experience these symptoms. There is no treatment or vaccine for hantavirus infection, but medical care can help reduce the symptoms during recovery.

Preventing Infection

People can be exposed to hantavirus when wild rodents invade their living area. Infected rodents shed the virus in their urine, feces and saliva. Once the matter dries, it can be stirred into the air where people could inhale the virus.

If people find wild rodents, nests or signs of them in their living spaces, they should always use “wet cleaning” methods – using bleach or other disinfectants, rubber gloves and bags. They should NOT sweep or vacuum, which could stir hantavirus into the air where it could be inhaled.

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 poop and urine.

Cover or put away pet food dishes when not in use

Store pet food in rodent-proof containers

Cover all trash cans with rodent-proof lids

Use mouse traps where there is evidence of mouse activity

Remove woodpiles, old cars, trash, and debris from property

Store hay or firewood at least 100 feet away from buildings

Cut grass, weeds, and trim bushes within 100 feet of buildings

Clean up rodent poop and urine using the “wet cleaning” methods described below.

“Wet-cleaning” Methods

Do not stir up dust and sweep or vacuum infested areas that have droppings, urine, or nesting materials.

Spray the disinfectant solution on polluted areas, including dead rodents or droppings, and let sit for 15 – 20 minutes before cleaning

Ventilate the affected area by opening doors and windows for at least 30 minutes before starting to clean.

Use rubber gloves. Spray a 10 percent bleach solution or other disinfectants onto dead rodents, rodent poop, nests, contaminated traps and surrounding areas, then 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 them 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 and Quality (DEHQ) at (858) 694-2888 or visit the DEHQ hantavirus web page at https://www.sandiegocounty.gov/content/sdc/deh/pests/hantavirus.html.

 
 
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