Residents of Berkeley, California, face a significant public health warning following the discovery of leptospirosis, a potentially fatal bacterial disease, in a local homeless encampment. This outbreak has raised concerns among pet owners and health officials as heavy rainfall has created conditions conducive to the bacteria’s survival and transmission.
Details of the Outbreak
The alert was issued by local health authorities after multiple rats and at least two dogs tested positive for leptospirosis near the Harrison Street encampment, situated by Codornices Creek. This disease is caused by Leptospira bacteria, which are typically spread through the urine of infected animals, particularly rats. While there have been no reported human cases to date, the potential risks to both animals and people are substantial, especially for those who might come into contact with contaminated soil or water.
According to Dr. Monica Gandhi, an infectious disease physician at the University of California, San Francisco (UCSF), dogs are at heightened risk because they may not avoid puddles in the same way humans do. “Dogs don’t avoid puddles the way people do,” she stated. “They’re much more likely to be exposed.” The bacteria can enter the body through cuts, eyes, the mouth, or mucous membranes.
The recent combination of warm weather followed by storms has created optimal conditions for the bacteria to thrive. Health officials have noted that leptospirosis can survive in soil or water for up to a month, thus prolonging the risk of exposure even after initial contamination.
Public Health Measures and Recommendations
In response to the outbreak, the city has designated the Harrison Street area as a “red zone” and strongly advised residents of the encampment to relocate at least one-third of a mile away. This initiative aims to facilitate focused cleanup, rat eradication, and enhance public safety measures. The city has not only posted warnings but also conducted environmental testing and urged pet owners to vaccinate their animals against leptospirosis. Additionally, owners of free-roaming cats are encouraged to consider vaccination, and all pet owners are advised to keep their animals away from potentially contaminated water.
Symptoms of leptospirosis can manifest as flu-like, including fever, chills, headache, sore muscles, or red eyes. Anyone who has spent time in the encampment and develops these symptoms should seek medical care immediately and inform healthcare providers of their potential exposure. Dog owners are also advised to watch for signs such as vomiting, jaundice, or abnormal urination and to seek urgent veterinary care if these symptoms arise.
Dr. Peter Chin-Hong, another infectious disease expert at UCSF, emphasized the risks associated with the combination of rats and heavy rainfall. “Wherever you get rats urinating and then flooding or rain, there’s potential for exposure,” he noted. The distinct incubation period for leptospirosis can be lengthy, and individuals may not immediately recall their exposure, making it critical for clinicians to inquire about contact with animals or contaminated environments.
In a public health release, Dr. Noemi Doohan, Berkeley’s public health officer, advised: “Neither dogs nor people should wade in, or drink from, nearby water, mud, puddles, or Codornices Creek. Provide clean water for your pets, and keep them away from sick or dead animals.”
Authorities in Berkeley are actively conducting a public health investigation into this outbreak, with expectations that cleanup and rat eradication efforts will take at least 30 days, which aligns with the typical lifespan of leptospirosis in soil. The city explained, “Eradication of rats requires many cycles of baiting with poison in their underground burrows, removing carcasses, and rebaiting over time.” This coordinated effort aims to mitigate the risk of further infections and protect the health of both residents and their pets.
