[ad_1]
In 2018, infectious disease experts from the University of Hong Kong came across an unusual case: A 56-year-old patient who had undergone a liver transplant showed abnormal liver function without a specific cause. The tests found that his immune system was responding to hepatitis E, but doctors did not find the human strain of the disease in his blood, writes CNN.
Hepatitis E is a liver disease that causes fever, jaundice, and an increase in the liver. The virus is found in four variants and only one was known to infect humans. After tests for the human strain were negative, the researchers redesigned the test and ran it several times, discovering for the first time in the world the hepatitis E strain that infects rats in humans.
“Suddenly, we have a virus that can jump from rats to humans,” said Dr. Siddharth Sridhar, a microbiologist and one of the researchers at the University of Hong Kong who made the discovery. It was such an unusual and unexpected case that doctors wondered if it was an isolated incident with a patient in the wrong place at the wrong time.
Then it happened again. So far, 11 Hong Kong residents have tested positive for the strain of hepatitis E found in rats. The most recent case is that of a 61-year-old man, diagnosed on April 30. Sridhar says there could be hundreds of people infected but undiagnosed.
The human strain of hepatitis E is spread by contaminating drinking water with feces, according to the World Health Organization (WHO).
The strain found in rats is a mystery: No one knows exactly how it came to infect humans. In the two years since the first case, scientists have been unable to establish the path from rat to human. There are theories, but none have been proven.
The latest case, the 61-year-old man, deepened the mystery: There were no rats or rat droppings in his home, no one in the home had symptoms, and the patient had not recently traveled. “According to available epidemiological information, the source and route of the infection could not be determined,” Hong Kong authorities said on April 30.
Progress has been made, but much remains to be known
Authorities and investigators have been trying to understand this threat for the past 2 years and there has been progress. However, many remain unknown. The incubation period for the virus is unknown, and effective treatment is still being attempted, as the drugs used to treat the human hepatitis E strain are not as effective in the rat strain.
How the infection is transmitted from rats to humans remains a mystery, making infection prevention difficult, but also drawing conclusions based on the data collected so far. For example, people living in rat-infested areas should be at higher risk for infection, but some patients came from areas where there are very few rats.
“What we do know is that Hong Kong rats carry the virus and when we examine the sick we find the virus. But the way it jumps from rat to human, if the rats somehow contaminate our food or if there is another animal involved, we don’t know, “says the epidemiologist. Srindhar. “That is the missing link.”
One solution would be to eradicate rats, but this is a very long and complicated process.
This situation could exist elsewhere.
“This situation is unlikely to exist only in Hong Kong, and it is not even recent,” experts say. The strain of rats with hepatitis E could infect people in other countries and not be known because it is not being tested.
“My view is that this has been going on for a long time,” says Srindhar. In Hong Kong, all 11 cases were detected because patients needed medical attention for pre-existing symptoms or illnesses and were tested.
Many people with hepatitis E have mild symptoms and, in some cases, do not even know they are infected and do not go to the hospital. However, hepatitis E can have serious consequences, especially in people with weakened immune systems. Healthy young people, without pre-existing diseases, can recover on their own.
In addition to the 11 cases in Hong Kong, there was only one confirmed case globally: a man from Canada who had traveled to Africa. Doctors were able to detect it only because they conducted numerous tests for different strains of hepatitis E, the researchers say in the study published in the Journal of Infectious Diseases.
Web editor: V.M.
