A study by Chinese and Singapore scientists identified 35 human patients of a new henipavirus of animal origin in two provinces in China, according to a letter published in the latest issue of the New England Journal of Medicine (NEJM). It is estimated that shrews could be the main reservoir of this pathogen, for which there are still no specific treatments or vaccines.
From the NEJM they explained that the Hendra virus and the Nipah virus, which belong to the henipavirus genus in the Paramyxoviridae family, are known to infect humans and cause fatal diseases; However, other related henipaviruses have been detected in bats, rodents, and shrews.
During sentinel surveillance of febrile patients with a recent history of animal exposure in eastern China, a phylogenetically distinct henipavirus , named Langya henipavirus (LayV) , was identified in a throat swab sample from one patient by metagenomic analysis.
The LayV genome is composed of 18,402 nucleotides with a genomic organization identical to that of other henipaviruses. LayV is most phylogenetically related to Mojiang henipavirus, which was discovered in southern China
Subsequent investigation identified 35 patients with acute LayV infection in the Chinese provinces of Shandong and Henan . Of that total, 26 were infected with LayV alone (no other pathogens were present).
These 26 patients presented fever (100% of them), fatigue (54%), cough (50%), loss of appetite (50%), myalgia (46%), nausea (38%), headache (35%). %), and vomiting (35%), accompanied by abnormalities of thrombocytopenia (35%), leukopenia (54%), and deterioration of liver (35%) and kidney (8%) function.
A serological survey of domestic animals detected seropositivity in goats (3 of 16, 2%) and dogs (4 of 79, 5%). Among the 25 species of small wild animals analyzed, LayV RNA was predominantly detected in shrews (71 of 262, 27%), a finding that suggests that the shrew may be a natural reservoir for LayV.
Although the current study does not meet Koch’s postulates, the following findings from patients with acute LayV infection suggest that this henipavirus was the cause of the febrile illness.
LayV was the only potential pathogen detected in 26 of the 35 patients (74%) with acute infection. In paired serum samples obtained from 14 patients during the acute and convalescent phases of infection, IgG titers in 86% of the convalescent phase samples were 4 times higher than those in the convalescent phase samples. acute phase.
Viremia was associated with acute LayV infection; and patients with pneumonia had higher viral loads than those without pneumonia (mean [±SD] log 10 -transformed copies per milliliter, 7.64±0.98 vs. 4.52±1.13).
There was no close contact or common exposure history between the patients, suggesting that infection in the human population may be sporadic. “Contact tracing of 9 patients with 15 close contact family members did not reveal close contact transmission of LayV, but our sample size was too small to determine the status of person-to-person transmission for LayV,” the publication stated. of the NEJM.
Possible cross-reaction with Mojiang virus should be evaluated to improve serological testing.
In the study cited by the letter, they highlight that the fact that a recently identified henipavirus of probable animal origin was associated with a febrile illness justifies further investigation.
