TAIPEI (Taiwan News) -- A 67-year-old man from Hong Kong man, who was diagnosed with rat Hepatitis E (HEV), had traveled to Taiwan during the incubation period earlier this year, reported Outbreak News Today.

The patient, along with an 81-year-old man were both diagnosed with the disease, but neither required hospitalization. However, a third patient aged 74, who had underlying illnesses and also contracted the disease, was admitted to Hong Kong's Tuen Mun Hospital on April 28, and died on May 4, according to the report.

According to HK01, the 67-year-old male had visited Taiwan in January and South Korea in February during the incubation period (IP), while the other two had not recently traveled. The Centre for Health Protection (CHP) of the Department of Health said that the three men were residents of Kowloon City, Southern District, and Tuen Mun, respectively.

None of the three patients reported having been in direct contact with rats, their excrement, or saw signs of the rodents in their dwellings.

Medical circles used to think that human hepatitis E virus belonging to species Orthohepevirus A and rat HEV belonging to species Orthohepevirus C had "species barrier" and that they could not interact with each other, so it is likely that this virus is a genetic mutation.

The world's first male patient was a 56-year-old man who underwent liver transplantation in Hong Kong in May of 2017 for hepatocellular carcinoma and chronic hepatitis B. Two months later, he was found to have developed persistent abnormal liver function. The hospital then tested the patient for anti-hepatitis E virus IgM antibody but was negative for the human strain of hepatitis E.

Finally, the hospital used a more accurate genetic test to confirm that he was infected with rat hepatitis E. After being provided with medication to treat hepatitis, his liver function gradually returned to normal.

According to the Hong Kong Centre for Health Protection, the exact route of transmission of hepatitis E from rats to humans is still unclear, as human infection is mainly transmitted through fecal and oral routes, such as drinking water contaminated by feces. In addition, hepatitis E can also be contracted by eating uncooked meat or meat products from infected animals (the hepatitis E virus has been detected in pig livers).