Pteropine orthoreovirus of Bat Origin: An Emerging Pathogen Associated with Cases of Acute Respiratory Infections

Abstract

Purpose: Pteropine orthoreovirus (PRV) is a bat-borne virus classified under the Reoviridae family. It is a recently emerging virus in Southeast Asia and has been associated with sporadic respiratory infections in humans. Despite its epidemic potential, PRV is often neglected during diagnosis for acute respiratory infection (ARI) and may be accountable for cases of unexplained ARI. The study aims to assess the molecular prevalence and analyze the genetic diversity of PRV in patients with ARI in an urban population. Methods & Materials: A total of 3,935 nasopharyngeal swabs were collected from outpatients experiencing ARI symptoms in Kuala Lumpur, Malaysia from 2012 to 2014. Specimens were screened for all established respiratory viruses using a multiplex molecular assay. PCR-negative swabs were then screened for the sigma 1/A gene (major inner capsid) of PRV. Molecular epidemiological investigation and phylogenetic analysis were conducted using the global PRV strains isolated from humans and non-human hosts. Results: Multiplex respiratory virus detection was negative for 49% of the patients. Among a subset of these patients (n=632), fourteen (2.2%) were tested positive for PRV. Patients (median age: 50.5, range 25-70 years old) were presented with mild to severe influenza-like illnesses. Phylogenetic analysis based on the sigma 1/A gene revealed thirteen (92.9%) patients infected with the Melaka virus (MelV)-like PRV. Limited inter-patient diversity of MelV-like PRV was estimated, suggesting a strong founding effect. Interestingly, a close ancestral relationship among MelV-like PRV strains isolated from the human and non-human (bats and monkey) hosts was observed. In addition, one patient was infected with the Pulau virus (PulV) previously found in fruit bats, indicating the first documented case of PulV-like PRV infection in human. Conclusion: PRV of bat origin is a common causative agent of underdiagnosed ARI in the urban population. The study highlights the molecular prevalence of PRV among patients with ARI and the genetic diversity of PRV in the urban population of Kuala Lumpur, Malaysia.