Queued viral emergence and risk of global exposure: Langya virus

Dear Editor, In this modern era, progress is the core indicator of any prosperous human civilization warranting close proximity of humans to different species residing in their native niche. Humans at their evolutionary pinnacle disrupted the nature’s equilibrium and the cost of this progress is always paid by both nature and mankind. The root cause of all the zoonotic spillovers is climate change and uncontrolled human interference with the native flora and fauna. The Influenza, Crimean Congo hemorrhagic fever, Ebola, Boca, Marburg, Lassa, MERS-CoV, SARS-CoV, Rift Valley fever, Zika, Nipah, Hendra viruses, etc., and many more queued have originated in different places, and spread across the globe. Similarly, Langyavirus (LayV) in Shandong and Henan provinces of eastern China has emerged as a new challenge amid global threats of the ongoing COVID-19 pandemic, monkeypox, and Marburg virus disease outbreak. The LayV belongs to the genus henipavirus, named after Hendra and Nipah virus which also causes fatal diseases in humans1. The LayV was first isolated from a patient’s throat swab sample and identified using phylogenetic and metagenomic analysis2. The LayV genome (18,402 nucleotides) and its organization are very similar to that of the other henipaviruses, especially the Mojiang henipavirus, which is spread by rats. Among all the henipaviruses that have been discovered so far, only Hendra, Nipah, and the recent LayV can infect humans3. A total of 35 patients were identified with acute LayV infection while monitoring patients at 3 hospitals in the eastern Chinese provinces of Shandong and Henan between April 2018 and August 2021. The LayV symptoms in humans include fever, anorexia, myalgia, fatigue, and respiratory distress1. Complications such as pneumonia, renal impairment, and hepatic dysfunction were also noted. However, severe complications leading to death have not yet been reported. Among 35 reported cases of LayV infection in China, the majority of them are farmers and factory workers, out of them 26 were infected with LayV pathogen alone (26/35=74%). The IgG titer was found more in patient sera during the acute and convalescent phases of infection; however, titer is more in the convalescent phase as compared with the acute phase. Researchers collected blood samples from domestic animals and 25 various species of small wild animals to find out from where the LayV might have originated from. The fact that LayV viral RNA was found in shrews showed that the virus could come from natural sources, like the hantavirus and mammarenavirus. More than 260 samples were taken from rodents and shrews to examine the presence of virus among which, over 25% were found positive for the LayV viral RNA4. In addition, the serosurvey of domestic animals have been carried out by researchers which detected 1.78% and 5% seropositivity in goats and dogs, respectively (Fig. 1)5. Although, anthroponosis has not been reported; more research in this direction is warranted to establish this fact. To prove the anthroponosis through contact, researchers followed 9 patients in a family of 15 members who were close together. Although, they have not found any evidence of contact transmission of LayV, but the sample size was the major limitation.Figure 1: Outbreak, transmission and symptoms of Langya virus (LayV) outbreak in China.For active surveillance of the LayV infection, it is important for the countries to work together in a dynamic and co-operative way so that the possibility of spillover by a new virus could be minimized. LayV infections can cause a global health scare in future, but this can be minimized by using nucleic acid diagnostics and antiviral drugs ahead of time. Aside from this, it is important to find the natural host as well as the carrier host to stop the spread and further evolution of the LayV, especially in China as China has become a center for the spread of many possible zoonotic viruses. Changes in the weather and the destruction of natural resources in China make it more likely that viruses will spread from animals to humans1. The recent zoonotic spread of the LayV virus surprised everyone; how easily viruses can evolve and spread from animals to human. With increasing world population, there is no clear distinction between the human and animal habitat, this forces the close contact between humans and animals, and which makes it more likely that a virus will transform and jump over to humans. As the LayV is an RNA virus which can mutate quickly, proper epidemiological studies, strengthened surveillance, and monitoring activities are very crucial for its timely containment. Moreover, putting one health approach into place and conserving natural resources will be a step toward saving the world from another pandemic in near future. Ethical approval None. Sources of funding None. Author contribution A.A.: conceived the idea. S.K.P.: retrieved the data. A.A., A.K.N., R.V., and N.K.C.: write up of manuscript. T.B.E.: reviewed and provided inputs. All authors approved the final version of the manuscript. Conflict of interest disclosures The authors declare that they have no financial conflict of interest with regard to the content of this report. Research registration unique identifying number (UIN) None. Guarantor Talha Bin Emran. Provenance and peer review Externally peer reviewed, not commissioned. Data statement No data sets were generated.