SAN DIEGO (CNS) — San Diego County Environmental Health and Quality officials announced today that a Western harvest mouse found near the Los Penasquitos Ranch House tested positive for hantavirus.
The mouse, the first detected with the disease in 2026, prompted county staff to remind residents to be cautious in dusty areas, which can attract rodents such as attics, sheds and garages.
People rarely come into direct contact with infected animals because wild rodents naturally avoid humans, health officials said.
There were a total of 16 cases of hantavirus reported in rodents in 2025.
While exposure to hantavirus is rare, people should be careful around wild rodents as there is no cure or vaccine for hantavirus, according to health officials.
Symptoms of hantavirus usually develop between one and eight weeks after exposure and include:
- Severe muscle aches
- Chills, fever or fatigue
- Headache or dizziness
- Nausea, vomiting, stomach pain and difficulty breathing
If signs of wild rodents such as nests or droppings are found in outbuildings, the county advises using "wet cleaning" methods such as bleach and disinfectant and not to sweep or vacuum, which could bring the virus up into the air to be inhaled.
If anyone thinks they may have been exposed to hantavirus, they are urged to seek medical attention immediately.
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