![\"\"](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/01\/webimage-encampementsweepJune4th2025AdahliaCole-1.png\")
Dogs, bikes and belongings lay on the sidewalk after being hastily moved out of the targeted zone during a sweep of the homeless encampment near 8th and Harrison streets on June 4, 2025. More recently, health officials have said they detected an outbreak of leptospirosis in the camp. Credit: Adahlia Cole for Berkeleyside<\/p>\n
City and county health officials\u2019 detection of a leptospirosis outbreak<\/a> in and around a longstanding Northwest Berkeley homeless encampment<\/a> has many in the neighborhood worried about what it means for them and their pets.\u00a0<\/p>\n Veterinarians found leptospirosis in two dogs within the encampment around Eighth and Harrison streets, both in November, one of which died, and later detected the illness in rats<\/a> for the first time in five years in Alameda County.<\/p>\n As of the Jan. 12 announcement there were no known human cases. City officials did not respond to Berkeleyside\u2019s inquiries, sent Thursday, as to whether that has changed. County officials said that they are continuing \u201cto monitor the area and trap rats,\u201d and \u201cto provide support to the residents of the encampment on their rodent issues.\u201d<\/p>\n The bacterial pathogen, rare in the developed world, is treatable with antibiotics, and there are vaccines for dogs and other animals.<\/p>\n Berkeleyside has compiled some information on the disease and its risks from public health and veterinary medicine experts, as well as city health officials.<\/p>\n Just how dangerous is leptospirosis?<\/p>\n According to the CDC there are only about 1 million human cases of leptospirosis a year, most of those in developing countries and primarily in tropical climates, since the bacterium thrives in wet environments. Of those cases about 60,000 end up becoming fatal. In 90%of cases, humans and animals recover without any treatment, according to a study<\/a> in the National Library of Medicine.<\/p>\n However uncommon in the United States and other wealthier countries, untreated cases of leptospirosis can lead to kidney and liver failure, meningitis and death. And because it is so rare, and its symptoms so common to other illnesses, doctors and veterinarians sometimes do not think to look for it.<\/p>\n \u201cMost people who are exposed don\u2019t get it \u2014 only about 10% get symptoms,\u201d Dr. Peter Chin-Hong, a professor of medicine and infectious disease specialist at the University of California, San Francisco, told Berkeleyside in a phone interview. And of that 10% who develop symptoms, only 10% \u2014 or about 1 in 100 people exposed \u2014 develop severe symptoms, Chin-Hong said.<\/p>\n The illness can be more dangerous to people who are immunocompromised or have diabetes, liver disease or kidney disease, Chin-Hong said.<\/p>\n In pregnant people the bacterium can pose a deadly risk to fetuses, according to the CDC.<\/p>\n Who can catch leptospirosis, and how?<\/p>\n A map from Berkeley health officials puts the epicenter of the outbreak at Eighth and Harrison streets. The \u201cred zone,\u201d or most at-risk parts of the neighborhood, are Harrison Street from Cedarwood Lane to 10th Street and two blocks each of Eighth, Ninth and 10th streets, one each on either side of Harrison.<\/p>\n In a lower-risk \u201cyellow zone,\u201d radiating out \u2153 of a mile from Eighth and Harrison, \u201cthere is no evidence of active transmission of leptospirosis or of unmitigated rat populations,\u201d according to the Jan. 12 announcement. \u201cHowever, proximity to the encampment red zone creates risk and need for prevention efforts.\u201d<\/p>\n Leptospirosis is zoonotic \u2014 meaning it can jump between species \u2014 but is not airborne, and not transmitted by coughing or sneezing. The most common route of transmission is by way of urine from infected animals, either directly or by way of contaminating water or mud. If animals drink contaminated standing water, or if the bacterium comes in contact with cuts or mucous membranes (eyes, mouths, noses) on people and animals, they can contract the disease.<\/p>\n The illness can spread by bites that break skin, or pass from infected mothers to their young. The bacterium can also linger on plants that have come into contact with contaminated water or mud, making it prudent to wash anything harvested in contaminated areas. While the bacterium can persist for months on end in contaminated water, it typically dies off when puddles and pools dry out, and is susceptible<\/a> to disinfectants and heat over 112 degrees Fahrenheit.<\/p>\n Wild animals that come into contact with the bacterium are at risk, but dogs are generally regarded as the most common domesticated animal to contract it.<\/p>\n Cats, too, can contract leptospirosis, though compared with dogs, frequently show much milder symptoms or no symptoms at all. But while the illness might not hurt a cat directly, an infected cat can continue to shed the bacterium for years, according to the Centers for Disease Control and Prevention<\/a>.<\/p>\n Leptospirosis can also spread to livestock and marine mammals. Sea lion populations along the California coast generally see surges of the illness every three to five years, though there was an unexpected surge in cases this summer, KTVU reported at the time<\/a>.<\/p>\n How do I prevent transmission?<\/p>\n![\"\"](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/01\/Image-1-23-26-at-4.09-PM.png\")
Health officials have recommended people take precautions if they pass within 1\/3 of a mile of the outbreak\u2019s epicenter, at Eighth and Harrison streets. Credit: City of Berkeley<\/p>\n