Discovery of the first human case of rat disease in the world

(CNN) – For the first time, a case of hepatitis E in rats was discovered in a human in Hong Kong.

A 56-year-old man has been diagnosed with the disease, researchers at the University of Hong Kong said. It was not known before that the disease could be transmitted from rats to humans.

"Previous laboratory experiments have shown that rat hepatitis E virus can not be transmitted to monkeys and that human hepatitis A virus can not be transmitted to rats," says Dr. Siddharth. Sridhar, clinical assistant at the University of Hong Kong. close to humans with respect to disease susceptibility.

Sridhar said at a press conference that the risk of contracting hepatitis E in the rat had been underestimated.

The man developed the disease after undergoing a liver transplant following chronic infection with hepatitis B. He continued to show signs of liver dysfunction, Sridhar said, with no obvious cause.

The investigations revealed signs of an immune response to hepatitis E, which is a major cause of viral hepatitis in humans around the world, he said. But the tests for the human form of the virus came back negative.

Genetic sequencing of the human-infecting virus then revealed similarities with the form of the disease in the rat and the man received antiviral treatment.

"The patient is cured, at this point, we can no longer detect the virus in any clinical specimen," Sridhar said.

The team then wanted to know how the disease could be transmitted from rats to humans and thought that the man had caught the disease in rats infesting a garbage chute near his home.

"The hepatitis E virus of rats now joins this list of infections as an important pathogen that can be transmitted from rats to humans," Sridhar said.

The team believes that the most important control measure would be to limit the rat population and ensure rats do not eat waste.

Martin Hibberd, professor of emerging infectious diseases at the London School of Hygiene and Tropical Medicine, said it was "very unlikely" that the virus could be transmitted between humans. He was not involved in the case.

The immune system of the Hong Kong patient was compromised because he had recently undergone a liver transplant, which exposed him to an increased risk of contracting an infection. "Most people are not, which means it probably is not common, usually in humans," Hibberd told CNN.

Since most people do not look for this virus, "we do not have any standard tests yet," he added.

"This concrete example means that we should probably start looking for more information, especially in immunocompromised people," Hibberd said. "The virus seems to be relatively diverse, suggesting that it's been around for a long time."

Hepatitis causes inflammation of the liver, with various viruses that cause it. Depending on the virus, hepatitis A, B, and C most often spread through contaminated food, water, blood, and other body fluids.

The human form of hepatitis E is usually transmitted by contaminated water. It is estimated that it infects 20 million people worldwide, or 3.3 million people with symptoms each year, according to the World Health Organization. It caused about 44,000 deaths in 2015, accounting for 3.3% of all deaths due to viral hepatitis.

The animal form of the disease is thought to infect wild boars, domestic pigs and deer, as well as rats and other rodents.

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