Increasing Cases Of Rats Infecting Humans With Hepatitis E Shock Scientists

Rats have been infecting humans with hepatitis and the bigger problem is that nobody even knows how it happened in the first place. Researchers say they have found evidence of rat hepatitis E in some patients in Hong Kong.

An Unusual Case

Two years ago, infectious disease experts from the University of Hong Kong came across an unusual case. A 56-year-old patient, who had gone through a liver transplant, started to experience abnormal liver functions for no obvious reason.

Tests showed that the immune system of the patient was responding to hepatitis E but doctors could not find the human strain of the virus in his blood. When researchers redesigned their diagnostic test and ran it again, they found for the first time in medical history, a strain of rat hepatitis E virus in a human.

Hepatitis E is a liver illness that causes jaundice, fever, and an enlarged liver. There are four varieties of the virus circulating in animals during that time and only one among them is known to infect humans. “Suddenly, we have a virus that can jump from street rats to humans," Dr. Siddharth Sridhar, a microbiologist and one of the HKU researchers who made the discovery, said.

Unusual And Unprecedented

At the time, the discovery of the infection was deemed unprecedented and very unusual that the research team thought it might be a one-off incident. However, it happened again to several more patients. Since that initial discovery, 10 more Hong Kong residents were found to be positive with rat hepatitis E, also called rat HEV.

The most recent case was a 61-year-old man who also experienced an abnormal liver function and, upon testing, was found to be positive for rat HEV on April 30. With the illness affecting more patients, Dr. Sridhar is inclined to believe there might be hundreds of people infected out there who remain undiagnosed.

A New Mystery

The World Health Organization stated that the human strain of hepatitis E is usually transmitted by drinking water contaminated by fecal matter. The rat strain, however, poses a mystery as no one knows how people are getting infected. Two years after it was discovered, scientists have yet to pinpoint the exact path of transmission from rats to humans.

While researchers have come up with theories as to how this may have happened, such as the rat strain contaminating drinking water, nothing has been proven with certainty. Health authorities are also stumped by the recent case of the 61-year-old patient as there were no rats or evidence of rat excrement in his home. Nobody in his household has experienced similar symptoms and the patient also has no recent travel history.

In an April 30 statement, Hong Kong’s Center for Health Protection (CHP) said that, based on their available epidemiological information, the route and source of infection could not be determined. The patient is still confined in the hospital and the investigation by the CHP is still ongoing.