The Paper's reporter Liu Dong
Recently, the world's authoritative medical journal New England Medicine (NEJM) published a communication article cooperated by Chinese and Singaporean scientists, which claimed that a new animal-derived henipavirus virus that can infect humans has been found in Shandong and Henan, China. The authors named it Langya henipavirus (LayV).
Professor Liu Wei, Professor Fang Liqun, Professor Wang Linfa of the Institute of Microbiology and Epidemiology of the Academy of Military Medicine of the Chinese Academy of Military Sciences, Professor Wang Linfa of the Duke-National University of Singapore School of Medicine, and other scholars pointed out in the study that a newly discovered Henipa virus that may come from animals is associated with some febrile cases, and the symptoms of these infected people include fever, fatigue, cough, anorexia, myalgia, nausea, etc. This finding deserves further research to better understand the associated human diseases.
"This virus belongs to the same genus as Nipah virus, and so far these cases have not been fatal or very serious. It can therefore be said that [we] should be vigilant, not panick, about this new virus. But we need to be careful, because there are more similar viruses in nature, and if a different virus jumps on humans, the situation may not be the same. One of the above researchers, Professor Wang Linfa of the School of Medicine of the National University of Singapore, told the surging news (www.thepaper.cn) on the 8th.
LayV natural host or shrew
Henipah virus is one of the important emerging causes of zoonotic diseases in the Asia-Pacific region. Two viruses in the genus are known to infect humans: Hendra virus (HeV) and Nipah virus (NiV). The natural hosts of both viruses are fruit bats. Both viruses cause serious disease in both animals and humans and are classified as biosafety class IV viruses with a case fatality rate of between 40 and 75 percent.
However, scientists have also found other associated Henipah viruses in bats, rodents, and shrews, a mammal of the family Spikys. In the study, during sentinel surveillance of fever patients with a recent history of animal exposure in eastern China, scientists discovered a new Henipa virus in a throat swab sample from one patient, named LayV, through high-throughput sequencing and virus isolation.
LayV's genome consists of 18402 nucleotides, and its genome organization is the same as that of other Hennipah viruses, and on the phylogenetic tree, it was found that this strain belongs to the new strain, and in terms of evolutionary relationship, it is most related to the Hennipah virus previously found in Mojiang, Yunnan.
Further investigation found that 35 patients with acute LayV infection were found in Shandong and Henan, China, of which 26 were infected with only LayV (no other pathogens were detected). The clinical symptoms of these 26 patients were fever (100%), fatigue (54%), cough (50%), anorexia (50%), myalgia (46%), nausea (38%), headache (35%), vomiting (35%), and accompanied by thrombocytopenia (35%), leukopenia (54%), impaired liver function (35%) and impaired renal function (8%).
In serological studies of livestock, goats (3/168 [2%]) and dogs (4/79 [5%]) were found to have positive serum antibodies. In the 25 wild small mammals studied, LayV's RNA (71/262 [27%]) was detected mainly in shrews, suggesting that shrews may be natural hosts for LayV.
The researchers note that while this study does not conform to the Koch hypothesis (a law used to establish causality between disease and microbes), the following findings from patients with acute LayV infection suggest that LayV is the cause of febrile disease in these patients: Of the 35 patients with acute LayV infection, 26 (74%) were detected only LayV; Of the acute and convalescent paired serums of 14 patients, 86% of the convalescent serum IgG titers were 4 times that of acute phase serum; Viremia is associated with acute LayV infection; The viral load in patients with pneumonia was higher than in non-pneumonic patients (average [±SD] log10 converted copies/mL, 7.64±0.98 vs. 4.52±1.13).
It has not been determined whether LayV can be passed on from person to person
While previous reports suggest that Henipa virus can spread from person to person, the researchers note that no cases and LayV haplotypes have been found to have significant aggregations in space or time. There is no history of close contact or co-exposure between patients, suggesting that infection in the population may be sporadic. No close contact transmission of LayV was found in the tracing of 9 patients with 15 family members, but the researchers also acknowledged that the human-to-human transmission of LayV could not be determined due to the small sample size, and possible cross-reactions between LayV and Hennipah virus found in Mojiang should be assessed to improve serological testing.
Finally, the researchers note that LayV, as a newly discovered Henipah virus that may be derived from animals, is associated with human febrile disease, a finding that warrants further study to better understand the associated human disease.
For Henipa virus, the World Health Organization states that once a suspected case appears, isolation should be implemented as soon as possible, and infection control measures should be taken to notify public health authorities immediately.
When humans are infected with Hendra virus, which belongs to Henipah virus, mild influenza-like illness may appear mild and severe cases may present with fatal respiratory or neurological diseases. The mortality rate of human infection with Hendra virus ranges from 50% to 75%. Fortunately, it is not very contagious. When humans are infected with Nipah virus belonging to Henipah virus, the mild can present as asymptomatic infection and the severity may present with acute respiratory syndrome and fatal encephalitis. In 1998, Nipah virus circulated in Malaysian pig herds and infected 265 people, including 105 deaths. The story was later adapted into the film Infectious Disease and became widely known.
There is currently no vaccine or treatment for Henipa virus. The only treatment is supportive care to control complications. The World Health Organization estimates that the case fatality rate of two known human-infecting Hennipah viruses (Hendra virus and Nipah virus) ranges from 40% to 75%, which is much higher than that of the new crown virus.
Responsible editor: Hu Zhenqing Photo editor: Zhang Tongze
Proofreader: Shi Gong