A strain of hepatitis found only in rats infected a Hong Kong man

How did it happen?
How did it happen?
Image: Reuters/Christian Hartmann
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For the first time, a man was infected with a strain of hepatitis E that was previously found only in rats.

Researchers in Hong Kong on Friday (Sept. 28) announced that a 56-year-old man had been diagnosed with an infection of rat hepatitis B. Though the man has been cured, the news put the densely populated city, scarred by the SARS epidemic in the early 2000s, on edge.

Yuen Kwok-yung, a microbiologist at the University of Hong Kong who was the lead researcher on the case, called the case a “wake-up call” for authorities to improve the city’s environmental hygiene since it’s believed the virus had spread through rat droppings. However, the scientists noted there isn’t an imminent threat of an epidemic.

“One is all it takes,” added Siddharth Sridhar, a clinical assistant professor at the university who was also involved in the case (paywall). ”For these kinds of rare infections, unusual infections, even one case is enough to make public health authorities and researchers very alert about the implications of the disease.”

Rat hepatitis E is different from the variant of hepatitis E humans normally contract, which affects the liver and is transmitted largely through contaminated water. The World Health Organization estimated 20 million people are infected by the hepatitis E virus every year. Typically, the disease resolves itself within two to six weeks, but it has a mortality rate of 3.3%, according to the organization. In 2015, about 44,000 people died from the disease.

The man who was infected with the rat variant of hepatitis E had received a liver transplant in May 2017. In September that year, scientists identified the infection, and he was cured of the disease in March. Though it remains unclear how the disease had transmitted from rats to him, researchers had ruled out it passing from the donor organ. They suspect the patient might have consumed food contaminated with rat droppings. Some experts think the infection was able to transmit to the patient because of his suppressed immune system, a result of medication he took to prevent his body from rejecting the donor organ.