Differentiating Langya Henipavirus From Common Illnesses

Introduction

The world still has not fully recovered from the shadow of the COVID-19 pandemic. However, in the first week of August 2022, another incident was reported where 35 patients were infected by a newly identified Henipavirus, named the Langya virus, in eastern China – a scenario that shared much similarity with COVID-19.¹

Henipavirus is under the family of Paramyxoviridae and so far eight different viral members have been discovered.^1,2 Among them, the Hendra virus and the Nipah virus are often under discussion in medicine due to them causing severe acute respiratory distress in humans and having high mortality rates.^1,3 

The public health concern has risen to different social media platforms since the Langya virus appeared. People are afraid of facing the nightmare of COVID-19 again. However, is it a true story? Today, the article aims to introduce the Langya virus and tell you the difference between this viral illness and other common viral illnesses. 

Overview of Langya virus

Langya virus is the latest identified virus in the genus Henipavirus under the family of Paramyxoviridae.³ The viral structure includes an envelope encasing single-stranded RNA, which comprises 18,402 nucleotides.⁴

At the first scene, the virus was detected in a throat swab sample from a patient in China, and it was found that the structure was genetically different from other viruses within the genus Henipavirus.¹ As a result, scientists named it the Langya henipavirus (LayV).¹

The current geographical distribution of the LayV is still under investigation and so far 35 patients have been confirmed to have the infection, all of whom remain in Shandong province and Henan province of eastern China.^1,3

The reason that the LayV appearance raised high concern in the public is that in the past, the other two viruses also belonging to the genus Henipavirus, the Handra and Nipah viruses, demonstrated zoonotic transmission and caused fatal neurological disease and acute respiratory distress syndrome in humans.⁵ Therefore, many scientists were worried about bringing another new wave of pandemic after the discovery of LayV.

According to the statistics published in Elsevier, 22 out of 35 patients with LayV infection work as farmers and the cases do not show particular spatial aggregation.¹ It indicates that LayV is most likely a zoonotic virus and not just limited to regional events as well. It could spread potentially to the large scale of a nation or even the globe. Because the 35 patients have no history of close contact or common exposure among them, it seems to eliminate the possibility of human transmission in this scenario.¹ However, the small cases still may not be able to reflect the true reality in the large-scale society and fully rule out the possibility of human transmission. 

Moreover, few cases show severe complications like kidney and liver failure after the viral infection.¹ As a result, it is important for physicians to further differentiate the LayV infection from the common illnesses in diagnosis and also crucial for the public to be aware of severe viral illness from the common illnesses.  

Clinical Presentation

The common cold refers to one or several viral infections that cause mild upper respiratory illnesses.⁶ Patients usually present with inflammation of mucosal membranes in the nasal passage and throat.⁶

The common cold is also highly contagious and can spread easily through aerosols when patients sneeze or cough into air.⁶ Then the airborne droplet would be inhaled by another person.⁶

30% to 50% of patients with common cold are infected by rhinovirus and, following this, 10% to 15% of common colds are caused by coronavirus. Influenza viruses account for 5% to 15% of common cold cases.⁷ 

Although patients with the LayV infections present with similar symptoms like common cold, which can be easily mistaken as being caused by the usual common cold viruses, some unusual symptoms may raise red flags for the public to do further investigation in hospital. 

Comparing Symptoms: Langya Henipavirus vs. Common Illnesses

As stated in Table 1, it is clear that patients with LayV infections share similar symptoms with common cold. It may be hard for the public to differentiate the LayV infection from the common cold. However, it is observed that approximately 14% of confirmed cases with LayV infection exhibited gingival bleeding (gum bleeding) and therefore required hospitalisation.⁸ The event of gingival bleeding corresponds to the sign of thrombocytopenia induced by LayV infection.^7,8 Therefore, the presence of gingival bleeding accompanied by other mild cold symptoms may be an initial signal of severe illness for the public and prompt them to go for hospitals early check-up.⁸

Diagnostic Methods

The laboratory diagnosis is made by performing a combination of tests. The common laboratory tests include the virus isolation from throat or cerebrospinal fluid (CSF), reverse transcription PCR of serum, and enzyme-linked immunosorbent assay (ELISA) of serum or CSF.³

Reverse transcription PCR of serum is used to transcribe viral RNA to DNA and amplify the DNA to measure the amount of virus in the sample. ELISA is a technique used to accelerate the immunoassay process in different laboratory tests to examine antibodies, antigens, protein, and hormones existing in blood samples.⁹ Immunoassay testing is also an important method to discover the interaction between antigens and antibodies in the laboratory setting.⁹ Different viruses carry out particular antigens which allow clinical scientists to identify viral categories precisely.⁹ The three methods mentioned play vital roles in allowing  physicians to diagnose LayV infections.

Treatment and management

Currently, there are no available antiviral medicines or valid vaccinations for LayV infections.¹⁰ The aim of disease treatment is supportive care, where medicines are provided to alleviate the symptoms induced by LayV like fever, cough, and stuffy nose.^3,10 An in vitro study has shown the effectiveness of Ribavirin, an antiviral drug, but further investigative in vivo studies and clinical trials are still required to confirm the drug therapeutic use.³

Complications and Prognosis

Patients with LayV infections present with mild signs and symptoms like fever (100%), fatigue (54%), cough (50%), and anorexia (50%), but there are still some patients who develop the complications of liver failure and kidney failure.^1,10

Prevention

Scientists have detected the LayV RNA species in goats (3 of 168 [2%]), dogs (4 of 79 [5%]), and shrews (71/162 [27%]) in the serosurvey of domestic animals.¹ The high incidence of RNA species in shrews may indicate the shrew is the natural reservoir of LayV because viruses require live hosts to supply nutrition for them to replicate in growth. From here, we can understand that travellers should avoid close contact with shrews and their faeces to prevent the LayV infections. However, the zoonotic transmission pathway is still not yet determined until further investigation is established in the future. 

Summary

Langya virus is the newly identified virus in the genus of henipavirus. The number of confirmed cases still remains small with only 35 patients and so far evidence for human-to-human transmission has not been found among the 35 cases. However, the possibility for human transmission cannot be ruled out with full certainty due to the small sample size of the studies performed. As a result, it is still important for physicians to differentiate the LayV infection from common illness. 

Gingival bleeding could be the initial sign of severe illness to prompt the public to go for early check-up in hospitals. The current treatments for LayV infections involve the supportive care of symptoms. The medicinal cures or vaccines are not currently available. It is paramount for the public to go for early check-ups in hospitals so they can avoid treatment delays and the development of severe complications.