The proven pathogen is a close relative of viruses that have been affecting animals and humans in the Asia-Pacific region for some time. No human-to-human transmission has yet been documented in the recent outbreak.
Like other pathogens, the new henipavirus is likely to come from the animal kingdom. Researchers have already been able to prove it in geese, among other things.
Without painting the devil on the wall: What researchers from China and Hong Kong report in a scientific article in the American journal “New England Journal of Medicine”., is somewhat reminiscent of the beginnings of the corona pandemic. Apparently, the team has tracked down a new virus that can infect people and make them sick. Like the corona pandemic virus, the pathogen is likely to have come from the animal kingdom and spread to humans.
The new find is not a new corona virus. Rather, it is closely related to the so-called Hendravirus and the so-called Nipahvirus. Both pathogens are collectively referred to as henipaviruses. They can cause flu-like illnesses in humans and animals, but also pneumonia and brain infections. The newly discovered pathogen also falls into the group of henipaviruses: it is called Langya henipavirus (LayV).
No fatal cases registered yet
As the scientists write, they discovered the new virus in the throat swab of a fever patient. In subsequent investigations in Shandong and Henan provinces, they identified another 34 patients with acute LayV infection. Only this pathogen could be detected in 26 of them.
The researchers therefore assume that the new virus triggered the symptoms of the disease in these people. These include fever, tiredness, cough, muscle aches and headaches, and vomiting. Some patients also had pneumonia, abnormalities in the blood or reduced liver and kidney function.
Very serious or even fatal cases of illness have apparently not yet been registered. There is therefore no reason to panic, according to media reports Linfa Wang, a scientist involved in the new study. However, the cases are definitely a reason for increased vigilance, since there are many viruses in nature that could lead to unpredictable results if humans are infected.
The henipaviruses, which appeared earlier, have already claimed a few fatalities. In the first recorded outbreak of the Hendra virus in Australia in 1995, 21 horses and two people fell ill; 14 of the animals and one person have died from the infection. Three more people have died in subsequent outbreaks of the virus.
Infection via contact with animals
Nipah virus was first identified in 1999 as the cause of a major disease outbreak in pigs and more than 100 people in Malaysia and Singapore. Some pig farmers developed severe encephalitis, from which every second pig died. Other Nipahvirus outbreaks occurred in Bangladesh, India and the Philippines.
The natural host of the already known henipaviruses are flying foxes of the genus Pteropus. They are found in South and Southeast Asia to Australia and are also found on Madagascar and some islands in the western Pacific. In previous outbreaks, humans have mainly been infected through contact with intermediate hosts (pigs for Nipahvirus and horses for Hendravirus). However, infection is also possible through contaminated plant food.
Human-to-human transmission has also been described for the Nipah virus. In a study in Bangladesh with 248 cases of infection, researchers were able to prove that a third had been infected by a contact person.
Such human-to-human transmission has not yet been registered with the new henipavirus. As the researchers write in the “New England Journal of Medicine”, they were unable to determine any temporal or local accumulation of cases of infection in their investigation. In addition, no virus transmission could be detected in contact tracing of 9 patients with 15 close contacts.
Case numbers too small for reliable statements
The scientists therefore assume that infections with the new pathogen in humans occur sporadically and in contact with infected animals and their excrements. They have already been able to isolate the pathogen from various domestic and wild animals such as geese, dogs and shrews. The scientists emphasize that the number of cases is still far too small to be able to rule out human-to-human transmission with this virus.
There are still no drugs that are specifically effective against henipaviruses. There is also no vaccine against the pathogen for humans. Experience from veterinary medicine shows that this could change if the outbreaks increase sharply. A Hendravirus vaccine for horses has been available to veterinarians since 2012. Since then, more than 120,000 horses have been immunized with it.