Molecular Identification of a Novel Hantavirus in Malaysian Bronze Tube-Nosed Bats (Murina aenea)

Detection of novel coronaviruses from dusky fruit bat (Penthetor lucasi) in Sarawak, Malaysian Borneo

BACKGROUND

Sarawak has one of the highest diversity of fruit bats species (family Pteropodidae) in Malaysia, with 19 species described. Most coronavirus (CoV) studies have mainly focused on insectivorous bats, resulting in a lack of information on CoVs present in frugivorous bats. In addition, bat CoV surveillance activities are lacking in Malaysia.

OBJECTIVES

Our study focuses on determining the presence of bat CoVs in dusky fruit bat (Penthetor lucasi).

METHODS

Guano samples belonging to P. lucasi were collected from Wind Cave Nature Reserve. The samples were screened for the presence of CoVs using validated hemi-nested consensus RNA-dependent RNA polymerase consensus primers.

RESULTS

The bat CoV positivity rate was 38.5% (n = 15/39), with the viruses belonging to two subgenera: Alphacoronavirus (α-CoV) and Betacoronavirus (β-CoV). Phylogenetic analysis revealed that CoVs from 14 samples of P. lucasi belong to the genus α-CoV and may represent previously described genetic lineages in insectivorous bats in Wind Cave. However, only one sample of P. lucasi was detected with β-CoV which is closely related to subgenus Nobecovirus, which is commonly seen in frugivorous bats.

CONCLUSIONS

This study provides the first available data on CoVs circulating in P. lucasi.

Use of a Novel Detection Tool to Survey Orthohantaviruses in Wild-Caught Rodent Populations

Orthohantaviruses are negative-stranded RNA viruses with trisegmented genomes that can cause severe disease in humans and are carried by several host reservoirs throughout the world. Old World orthohantaviruses are primarily located throughout Europe and Asia, causing hemorrhagic fever with renal syndrome, and New World orthohantaviruses are found in North, Central, and South America, causing hantavirus cardiopulmonary syndrome (HCPS). In the United States, Sin Nombre orthohantavirus (SNV) is the primary cause of HCPS with a fatality rate of ~36%. The primary SNV host reservoir is thought to be the North American deer mouse, Peromyscus maniculatus. However, it has been shown that other species of Peromyscus can carry different orthohantaviruses. Few studies have systemically surveyed which orthohantaviruses may exist in wild-caught rodents or monitored spillover events into additional rodent reservoirs. A method for the rapid detection of orthohantaviruses is needed to screen large collections of rodent samples. Here, we report a pan-orthohantavirus, two-step reverse-transcription quantitative real-time PCR (RT-qPCR) tool designed to detect both Old and New World pathogenic orthohantavirus sequences of the S segment of the genome and validated them using plasmids and authentic viruses. We then performed a screening of wild-caught rodents and identified orthohantaviruses in lung tissue, and we confirmed the findings by Sanger sequencing. Furthermore, we identified new rodent reservoirs that have not been previously reported as orthohantavirus carriers. This novel tool can be used for the efficient and rapid detection of various orthohantaviruses, while uncovering potential new orthohantaviruses and host reservoirs that may otherwise go undetected.

Zoonotic disease and virome diversity in bats

The emergence of zoonotic viral diseases in humans commonly reflects exposure to mammalian wildlife. Bats (order Chiroptera) are arguably the most important mammalian reservoir for zoonotic viruses, with notable examples including Severe Acute Respiratory Syndrome coronaviruses 1 and 2, Middle East Respiratory Syndrome coronavirus, henipaviruses and lyssaviruses. Herein, we outline our current knowledge on the diversity of bat viromes, particularly through the lens of metagenomic next-generation sequencing and in the context of disease emergence. A key conclusion is that although bats harbour abundant virus diversity, the vast majority of bat viruses have not emerged to cause disease in new hosts such that bats are better regarded as critical but endangered components of global ecosystems.

Ecological surveillance of bat coronaviruses in Sarawak, Malaysian Borneo

Objective

Coronaviruses (CoVs) are natural commensals of bats. Two subgenera, namely Sarbecoviruses and Merbecoviruses have a high zoonotic potential and have been associated with three separate spillover events in the past 2 decades, making surveillance of bat-CoVs crucial for the prevention of the next epidemic. The study was aimed to elucidate the presence of coronavirus in fresh bat guano sampled from Wind Cave Nature Reserve (WCNR) in Sarawak, Malaysian Borneo. Samples collected were placed into viral transport medium, transported on ice within the collection day, and preserved at − 80 °C. Nucleic acid was extracted using the column method and screened using consensus PCR primers targeting the RNA-dependent RNA polymerase (RdRp) gene. Amplicons were sequenced bidirectionally using the Sanger method. Phylogenetic tree with maximum-likelihood bootstrap and Bayesian posterior probability were constructed.

Results

CoV-RNA was detected in ten specimens (47.6%, n  = 21). Six alphacoronavirus and four betacoronaviruses were identified. The bat-CoVs can be phylogenetically grouped into four novel clades which are closely related to Decacovirus-1 and Decacovirus-2, Sarbecovirus, and an unclassified CoV. CoVs lineages unique to the Island of Borneo were discovered in Sarawak, Malaysia, with one of them closely related to Sarbecovirus. All of them are distant from currently known human coronaviruses.

Coumarin Derivative N6 as a Novel anti-hantavirus Infection Agent Targeting AKT

Hantaviruses are globally emerging zoonotic viruses that can cause hemorrhagic fever with renal syndrome (HFRS) in Asia and Europe, which is primarily caused by Hantaan virus (HTNV) infection, results in profound morbidity and mortality. However, no specific treatment is available for this disease. Coumarin derivatives have been reported as antiviral molecules, while studies about the bioactivity of coumarin derivatives against HTNV infection are limited. To study the potential antiviral activity of coumarin derivatives, 126 coumarin derivatives are synthesized, and their inhibitory activity against HTNV is analyzed in vitro. Among these compounds, N6 inhibits HTNV with relatively high selectivity index at 10.9, and the viral titer of HTNV is reduced significantly after 5, 10, and 20 μM N6 treatments. Furthermore, the administration of N6 at the early stage of HTNV infection can inhibit the replication and production of infectious HTNV in host cell, this therapeutic efficacy is confirmed in HTNV-infected newborn mice at the early stage of infection. The molecular docking results show that N6 forms interactions with the key amino acid residues at its active site, and reveals several molecular interactions responsible for the observed affinity, and the treatment of N6 can inhibit the expression of p (Ser473)Akt and HTNV nucleocapsid protein significantly. As such, these observations demonstrate that coumarin derivative N6 might be used as a potential agent against HTNV infection.

The Serological Cross-Detection of Bat-Borne Hantaviruses: A Valid Strategy or Taking Chances?

Bats are hosts of a range of viruses, and their great diversity and unique characteristics that distinguish them from all other mammals have been related to the maintenance, evolution, and dissemination of these pathogens. Recently, very divergent hantaviruses have been discovered in distinct species of bats worldwide, but their association with human disease remains unclear. Considering the low success rates of detecting hantavirus RNA in bat tissues and that to date no hantaviruses have been isolated from bat samples, immunodiagnostic tools could be very helpful to understand pathogenesis, epidemiology, and geographic range of bat-borne hantaviruses. In this sense, we aimed to identify in silico immunogenic B-cell epitopes present on bat-borne hantaviruses nucleoprotein (NP) and verify if they are conserved among them and other selected members of Mammantavirinae, using a combination of (the three most used) different prediction algorithms, ELLIPRO, Discotope 2.0, and PEPITO server. To support our data, we in silico modeled 3D structures of NPs from representative members of bat-borne hantaviruses, using comparative and ab initio methods due to the absence of crystallographic structures of studied proteins or similar models in the Protein Data Bank. Our analysis demonstrated the antigenic complexity of the bat-borne hantaviruses group, showing a low sequence conservation of epitopes among members of its own group and a minor conservation degree in comparison to Orthohantavirus, with a recognized importance to public health. Our data suggest that the use of recombinant rodent-borne hantavirus NPs to cross-detect antibodies against bat- or shrew-borne viruses could underestimate the real impact of this virus in nature.