Here we go again: distinct henipavirus, named Langya henipavirus (LayV), identified in throat swab from one patient during sentinel surveillance of febrile patients recent history of animal exposure
by Paul Alexander
DOCTORS in China have sounded the alarm over a newly detected virus. “Langya” virus has infected 35 people so far in two provinces in eastern China, Taiwan's Centers for Disease Control (CDC) said.
Subsequent investigation identified 35 patients with acute LayV infection in the Shandong and Henan provinces of China, among whom 26 were infected with LayV only (no other pathogens were present). These 26 patients presented with fever (100% of the patients), fatigue (54%), cough (50%), anorexia (50%), myalgia (46%), nausea (38%), headache (35%), and vomiting (35%), accompanied by abnormalities of thrombocytopenia (35%), leukopenia (54%), and impaired liver (35%) and kidney (8%) function. A serosurvey of domestic animals detected seropositivity in goats (3 of 168 [2%]) and dogs (4 of 79 [5%]). Among 25 species of wild small animals surveyed, LayV RNA was predominantly detected in shrews (71 of 262 [27%]), a finding that suggests that the shrew may be a natural reservoir of LayV. (Additional details of the study are provided in the Supplementary Methods section in the Supplementary Appendix, available with the full text of this letter at NEJM.org.)
Although the current study does not fulfill Koch’s postulates, the following findings from the patients with acute LayV infection suggest that LayV was the cause of febrile illness: LayV was the only potential pathogen detected in 26 of the 35 patients (74%) with acute LayV infection; in paired serum samples that were obtained from 14 patients during the acute and convalescent phases of infection, the IgG titers in 86% of the convalescent-phase samples were 4 times as high as those in the acute-phase samples; viremia was associated with acute LayV infection; and the patients with pneumonia had higher viral loads than those without pneumonia (mean [±SD] log10-transformed copies per milliliter, 7.64±0.98 vs. 4.52±1.13). Although human-to-human transmission has been reported for the Nipah virus,5 we found no obvious spatial or temporal aggregation of human cases or the assigned haplotypes on the basis of three common single-nucleotide polymorphisms (Figure 1C). There was no close contact or common exposure history among the patients, which suggests that the infection in the human population may be sporadic. Contact tracing of 9 patients with 15 close-contact family members revealed no close-contact LayV transmission, but our sample size was too small to determine the status of human-to-human transmission for LayV. The potential cross-reaction with Mojiang virus should be assessed to improve serologic testing.