Health officials are closely watching developments in Hong Kong, where the second known case of rat hepatitis jumping to humans has been recorded. Researchers first identified a case of rat hepatitis E in a 56-year-old man last month. The second case involves a woman who lived about a mile away from the man in the Wong Tai Sin district and was infected with what researchers say was an "uncannily similar" strain of the virus, the Guardian reports. The 70-year-old woman, who had a compromised immune system, was infected within weeks of the man last year, researchers believe. They discovered the case after testing blood samples from more than 70 hepatitis E patients.
Hong Kong's health department says the woman did have direct contact with rodents and does not recall seeing any in her home, CNN reports. Researchers believe that the risk of rat hepatitis—which affects around 10% of rats, according to one study—jumping to humans has probably been underestimated. "Rat hepatitis E virus now joins this list of infections as an important pathogen that may be transmitted from rats to humans," says Dr. Siddharth Sridhar at the University of Hong Kong. Authorities say rat-contaminated food and water is the likeliest source of infection, and have urged the public to keep hands and utensils clean and make sure their food is thoroughly cooked. (Los Angeles, meanwhile, is dealing with an outbreak of typhus.)