After the Covid, already a new pandemic? Several articles published on Tuesday report that a new virus that has sickened 35 people has been identified in China. But what some media that talk about this discovery do not say is that these 35 patients were taken care of from April 2018 to August 2021. So it is not an ongoing epidemic in recent weeks. .
It all starts with a study by researchers from universities or institutes in China, Singapore and Australia, published on August 4 in the New England Journal of Medicine (NEJM). They were looking for possible zoonoses, that is to say diseases transmitted by animals to humans. Their survey was carried out in three Chinese hospitals, from April 2018 to August 2021, among patients suffering from acute fever (≥38°C) and who had been exposed to animals in the month before the onset of symptoms.
A new virus of the henipavirus genus of the Paramyxoviridae family, baptized Langya henipavirus (LayV), has been identified. “This family is known and includes in particular the Nipah and Hendra viruses from bats, which are closely monitored in humans because they are responsible for serious and potentially fatal diseases”, describes virologist Yannick Simonin. The Nipah virus is known to be able to be transmitted between humans and its fatality rate is 40 to 75%, according to the World Health Organization.
What about Langya henipavirus? 35 patients infected, including 26 only by this one, have been identified in three years. These 26 patients were 60 years old on average. All had fever, half of them were victims of fatigue, cough or muscle pain. A third had headaches. These symptoms were quite severe, but none of these patients apparently died (the authors do not specify).
“Sporadic” infection in the human population?
Important point: following an epidemiological survey of these patients infected with Langya henipavirus, “there was no close contact or common exposure history”, write the authors. This “suggests that infection in the human population may be sporadic”.
To find out which animal is the source of all these contaminations, the scientists went to investigate in the village of residence of the patients. Among all the small wild species studied, the shrew stands out as a potential natural reservoir of Langya henipavirus. “If there is no transmission from man to man, it is difficult to imagine a real epidemic because not everyone is exposed to shrews”, comments François Balloux, director of the Institute of Genetics at University College London.
Origin in China, virus originally transmitted by an animal… The scientist says he “understands the fears generated” by this discovery and “the fact that people see a parallel with SARS-CoV-2”. “But at this point, with 35 cases (from Langya henipavirus) identified in three years, there is no heavy traffic and all this has nothing to do with the Covid-19”, reassures François Balloux. “Each year, several viruses emerge in humans without causing epidemics. It has been circulating quietly for several years and we are not in an emergency situation as was the case with SARS-CoV-2. There are no particular concerns at this stage, but the need for additional studies”, abounds Yannick Simonin.
The authors who published in the NEJM believe that “this finding warrants further investigation to better understand the human disease” associated with these infections. Above all, this emergence is a reminder that viruses potentially dangerous to humans can be transmitted by animals.