Berkeley officials respond to deadly leptospirosis outbreak

A leptospirosis outbreak linked to rat infestations has resulted in one death and one recovery in Berkeley, California. The victims were living in a severely rat-infested RV located approximately one mile from the Harrison Street homeless encampment at Eighth and Harrison streets.

Leptospirosis is a potentially deadly flu-like disease transmitted through contact with the urine of infected animals. While typically found in tropical climates, officials in Berkeley identified the disease after veterinarians treated sick dogs in December 2025. Testing subsequently confirmed that rats within the encampment were carrying the bacteria.

Berkeley officials had previously declared the sprawling encampment a public nuisance and a fire hazard. Following court approval, authorities began clearing the site to address the public health crisis and mounting concerns regarding the rat population.