Bay Area veterinarians report spike in deadly, contagious disease affecting dogs

February 12, 2026 - 16:40

A concerning rise in cases of leptospirosis, a potentially fatal bacterial disease, is being reported by veterinary clinics across the San Francisco Bay Area. The illness, which can lead to severe kidney and liver failure, is transmitted through contact with water, soil, or food contaminated by the urine of infected animals, including rodents, wildlife, and other dogs.

Veterinarians are urging dog owners to ensure their pets are vaccinated against this zoonotic disease, which can also spread to humans. Symptoms in dogs can include fever, lethargy, vomiting, diarrhea, and increased thirst or urination, but some infected animals may show no signs at all until the disease is advanced.

Veterinarians advise that vaccinations and early treatment for leptospirosis are crucial for survival. The treatment typically involves antibiotics and supportive care, but the window for effective intervention is narrow. The recent spike in cases, often linked to standing water after rains or exposure in parks and hiking trails, has put the veterinary community on high alert. Pet owners are encouraged to consult their veterinarians about the leptospirosis vaccine, limit their dog's access to stagnant water, and seek immediate medical attention if any symptoms appear.