Hepatitis E: A New Viral Outbreak Transmitted by Rats

Rat hepatitis E can infect humans. This mode of transmission, which remains largely a mystery, is cause for concern. Although only a few dozen cases have been detected, researchers warn that there are likely many more infections that have gone unnoticed.   In 2018, infectious disease experts at the University of Hong Kong were confronted with the emergence of a new virus. They were treating a 56-year-old man who had undergone a liver transplant and was presenting with abnormal liver function for no apparent reason. While tests indicated an immune response to hepatitis E, no human strain of the hepatitis E virus (HEV) was detected in his blood. HEV generally affects the liver in four animal species, causing fever, jaundice, and liver enlargement. At the time, only one strain appeared to infect humans. But researchers have now identified, for the first time, rat hepatitis E in a human. Since that initial study, 10 other Hong Kong residents have tested positive for rat hepatitis E. The most recent case occurred less than 15 days ago. But this may be just the tip of the iceberg. It is possible that the number of undiagnosed infections actually runs into the hundreds and that this has been going on for much longer. Many people with hepatitis E experience only mild symptoms and, in some cases, are not even aware that they are infected. For now, authorities can only issue warnings, raise awareness, and encourage preventive measures. While treatment for human hepatitis E appears to be effective, the results remain mixed. And the infection seems very difficult to prevent until the mode of transmission is identified. According to the World Health Organization, the human strain of hepatitis E is generally transmitted through fecal contamination of drinking water. However, no one yet knows for certain how the rat strain causes infection. It may be through drinking water or handling contaminated objects. Unfortunately, for the time being, the source, route of infection, and incubation period remain unknown. In the meantime, diagnostic tests have been refined and improved, and awareness campaigns targeting the hospital sector and the general public have been launched. City rats are also being tested in an effort to identify risk areas. This is a situation to watch closely!