A rat-borne illness has tragically claimed its first human victim in Berkeley in over ten years. Health officials reported that this startling case involved a recreational vehicle swarming with rodents, necessitating the removal of nearly 200 rats before the vehicle was ultimately destroyed.
City officials announced that one individual died in May after contracting leptospirosis, a dangerous bacterial infection typically spread through the urine of infected animals, notably rodents. Another person living with the victim survived, but they had needed a long hospital stay.
Both individuals were residing in an RV close to a significant homeless encampment in North Berkeley, which has been at the center of an ongoing leptospirosis outbreak among rats and dogs since late 2025.
According to City Administrator Paul Buddenhagen, the two residents were using the RV to trap, feed, and breed wild rats, with officials describing it as “heavily infested.” After vector control crews intervened, approximately 200 rats were removed from the RV prior to its towing and destruction.
In a memo addressed to the city council, Buddenhagen indicated that the two individuals “fell ill but did not seek medical care for weeks or even months.” This delay likely exacerbated the severity of the disease.
The victim sadly passed away shortly after being admitted to the hospital; in contrast, the other individual managed to recover.
Dr. Peter Chin-Hong, an infectious disease expert at the University of California, San Francisco, emphasized that the sheer number of rodents significantly heightens the risk of infection. “As the rat population increases, so does the volume of urine, which raises the chances that at least one rat will be infected,” he explained, adding that having only one rat is akin to “playing rat roulette.”
Leptospirosis typically presents with flu-like symptoms, including fever, chills, headache, muscle aches, nausea, and vomiting, but it can escalate to severe organ failure.
“This illness has two stages,” Chin-Hong noted. “The first consists of symptoms resembling the flu.”
Even with this tragic outcome, Chin-Hong pointed out that leptospirosis is generally treatable if caught early on. “There’s no reason for anyone to die from leptospirosis,” he asserted. “It’s a bacterial disease and can be effectively treated with antibiotics, which are readily available in hospitals.”
