World's First Human Case Of Rat Hepatitis E Discovered In Hong Kong

A 56-year-old Hong Kong man has developed the world's first ever human case of the rat version of the hepatitis E virus (HEV), the University of Hong Kong revealed Thursday night. Warning that the discovery had "major public health significance,” HKU said there had been no previous evidence that the disease could jump from rats to humans.

"This study conclusively proves for the first time in the world that rat HEV can infect humans to cause clinical infection," the university said.

The case emerged at HKU’s teaching hospital, Queen Mary, on May 14, 2017, when a man who had undergone a liver transplant showed persistently abnormal results for liver function tests. Further tests revealed the patient was carrying a species of hepatitis virus that was known to be present only in rats, since the virus was “highly divergent” from the strain that affects humans. HKU researchers who studied the case said the man was living in a housing estate “with evidence of rat infestation in the refuse bins outside his home.”

“We postulate that contamination of food by infected rat droppings in the food supply is possible,” they said. The route of transmission of the virus was not determined with certainty, however, South China Morning Post reported.

According to the report, the man had noticed rodent droppings but had not seen rats inside his home. However, the tests on rodent droppings, swab samples from the drain, floor from the refuse room, and even rats in the area, tested negative for the virus. The man was being treated with oral medications and was responding to treatment.

Hong Kong has been experiencing rodent infestations during its hot and humid summers. The hygiene authorities have been producing a rodent infestation index on areas they manage since the past 18 years. According to last year’s report, the rodent infestation rate (RIR) for the city as a whole was 3.5 percent. This was down from 4 percent recorded in 2016.

According to the World Health Organization, the human version of HEV affects 20 million people globally each year. It is a liver disease which usually spreads through contaminated drinking water. However, patients can also ingest the virus from eating undercooked meat from infected animals or get it through blood transfusions from infected donors. The symptoms of the disease include fever, reduced appetite, abdominal pain and jaundice. In some cases, it can also result in acute liver failure and death.

There is no specific treatment capable of altering the course of acute hepatitis E and the disease is usually self-limiting. The disease can be prevented by maintaining quality standards for public water supplies, establishing proper disposal systems for human feces and maintaining hygienic practices.