Deer Mouse Tests Positive for Hantavirus in California

San Diego County has reported its first hantavirus case of 2025, detected in a deer mouse from Cuyamaca Rancho State Park. While hantavirus is common in wild rodents, human contact is rare, and the virus, which has no cure or vaccine, can be deadly. Symptoms include severe muscle aches, fever, fatigue, and respiratory issues, developing one to eight weeks after exposure. Health officials recommend avoiding contact with rodents and using 'wet cleaning' methods with disinfectants, not sweeping or vacuuming, to prevent aerosolizing the virus. In 2024, the county recorded 25 cases, an increase from 17 in 2023. Residents are urged to seek medical attention if exposure is suspected and to seal potential rodent entry points in homes.