What is Langya Henipavirus (LayV)?
As the world continues to face significant challenges with SARS-CoV-2 and monkeypox viruses, a group of researchers from China, Singapore, and Australia has recently identified a formerly unknown and phylogenetically distinct henipavirus called Langya henipavirus (LayV). Although further investigations are required to determine its viral characteristics and behavior, the discovery of the novel virus has caused significant concern regarding whether it could be capable of causing a new pandemic. Read along to learn the latest information on Langya henipavirus (LayV), its potential sources, transmission, and symptoms, and find out more about the most recent updates on the options of testing, vaccination, and treatment available for the treatment of Langya henipavirus (LayV).
What causes Langya Henipavirus (LayV)?
Langya henipavirus (LayV) is a zoonotic henipavirus classified in the family Paramyxoviridae. It was detected during sentinel surveillance of febrile patients with a recent history of animal exposure in China. The virus was discovered in a throat swab specimen of a patient through metagenomic analysis and virus isolation. Subsequent investigations have revealed that the Langya henipavirus (LayV) has caused a total of acute infections in a total of 35 patients) in the Henan and Shandong provinces of northeastern China since 2018. Sharing the same genus, the Langya henipavirus (LayV)is closely related to the Nipah virus and the Hendra virus which are known to infect humans and cause potentially fatal disease, along with other henipaviruses found in bats, rodents, and shrews. However, the phylogenetically closest relative of Langya henipavirus (LayV) was found to be the Mojiang henipavirus, which was identified in southern China.
What is the natural host of Langya Henipavirus (LayV)?
Further investigations are required to determine the exact natural reservoir of the Langya henipavirus (LayV). However, a serosurvey performed by Zhang et al. (2022) has identified the shrew as a potential natural reservoir of LayV. Indeed, the serosurvey has revealed that among the 25 species of wild small animals surveyed, shrews displayed the highest level of seropositivity with a 27% detection rate. On the other hand, the serosurvey of domestic animals identified lower levels of seropositivity in goats and dogs with 2% and 5% detection rates, respectively. These findings suggest that Langya henipavirus (LayV) can affect various species such as humans, dogs, goat, and its likely natural host, shrews.
How does Langya Henipavirus (LayV) transmit?
While human-to-human transmission has been reported for the Nipah virus, which is a close relative of the Langya henipavirus (LayV), the study has found no significant evidence to suggest that the virus transmits between people. In fact, the study has identified no significant spatial or temporal aggregation of human cases. Moreover, there was no signs of close contact or common exposure history among the 35 people with confirmed infections. Contact tracing of 9 patients with 15 close contact family members has found no evidence for human-to-human transmission through close contact. Altogether, these findings suggest that infections with Langya henipavirus (LayV) detected within the human population may be sporadic. The researchers also noted that human-to-human transmission is uncommon among henipaviruses. So far, the only known member of the henipavirus genus to show signs of transmitting between people is the Nipah virus, which requires very close contact. Although the researchers have acknowledged that their sample size was insufficient to completely rule out the potential of human-to-human transmission for Langya henipavirus (LayV), these findings suggest that the virus is unlikely to cause a pandemic.
What are the signs and symptoms of Langya Henipavirus (LayV)?
Consecutive investigations by Zhang et al. (2022) have found that among the 35 patients with confirmed acute Langya henipavirus (LayV) infections, 26 people were infected with no other pathogens. Common signs and symptoms observed in the 26 patients infected exclusively with the Langya henipavirus (LayV) include fever (100% of the patients), fatigue (54%), cough (50%), anorexia (50%), myalgia (46%), nausea (38%), headache (35%), and vomiting (35%). These symptoms may be accompanied by abnormalities of thrombocytopenia (35%), leukopenia (54%), impaired liver function (35%), and impaired kidney (8%) function.
As of August 2022, no deaths linked to infection with Langya henipavirus (LayV) have been reported. Thankfully, the Langya henipavirus (LayV) appears to be less fatal and pathogenic compared to its siblings that are known to infect and cause disease in humans. In fact, according to the World Health Organization (WHO), the Nipah virus has a 75% fatality rate. On the other hand, Centers for Disease Control and Prevention (CDC) reports that the Hendra virus has a 57% fatality rate. While further investigations are required to determine the pathogenicity of and the fatality risk posed by the Langya henipavirus (LayV), current data suggests that LayV infections may be relatively less severe and deadly.
What are the options of testing, vaccination, and treatment for Langya Henipavirus (LayV)?
Similar to other henipaviruses such as the Nipah virus and the Hendra virus, there are currently no approved treatments or vaccines against Langya henipavirus (LayV) available for use in humans. However, according to Broder et al. (2013), a human monoclonal antibody targeting the viral G glycoprotein has been identified as an efficient treatment against infections with Hendra and Nipah viruses. Moreover, a sub-unit vaccine based on the G glycoprotein of Hendra virus developed for use in horses has been demonstrated to be effective against Hendra and Nipah viruses. Alongside these developments, antiviral agents such as ribavirin has been demonstrated to be effective in the treatment of Hendra and Nipah viruses. In the future, these advances may offer options for treatment and vaccination against infections with the Langya henipavirus (LayV).
With regards to testing options, there are currently no approved test kits for the detection for Langya henipavirus (LayV). However, the CDC Deputy Director-General Chuang Jen-Hsiang of the Taiwan Centers for Disease Control has recently reported that Taiwanese researchers have developed a polymerase chain reaction (PCR)-based testing method for the diagnosis and surveillance of the Langya henipavirus (LayV). On the other hand, there are currently no projects under development for alternative testing options such as rapid antigen testing or antibody testing.
References
Zhang XA, Li H, Jiang FC, Zhu F, Zhang YF, Chen JJ, Tan CW, Anderson DE, Fan H, Dong LY, Li C, Zhang PH, Li Y, Ding H, Fang LQ, Wang LF, Liu W. A Zoonotic Henipavirus in Febrile Patients in China. The New England Journal of Medicine. 2022 Aug 4;387(5):470-472. DOI: 10.1056/NEJMc2202705. PMID: 35921459. https://pubmed.ncbi.nlm.nih.gov/35921459/
Broder CC, Xu K, Nikolov DB, Zhu Z, Dimitrov DS, Middleton D, Pallister J, Geisbert TW, Bossart KN, Wang LF. A treatment for and vaccine against the deadly Hendra and Nipah viruses. Antiviral Research. 2013 Oct;100(1):8-13. DOI: 10.1016/j.antiviral.2013.06.012. PMID: 23838047; PMCID: PMC4418552. https://pubmed.ncbi.nlm.nih.gov/23838047/
