Coronaviruses (CoV) are divided into the genera α-CoVs, β-CoVs, γ-CoVs and δ-CoVs. Of these, α-CoVs and β-CoVs are solely capable of causing infections in humans, resulting in mild to severe respiratory symptoms. Bats have been identified as natural reservoir hosts for CoVs belonging to these two genera. Consequently, research on bat populations, CoV prevalence in bats and genetic characterization of bat CoVs is of special interest to investigate the potential transmission risks. We present the genome sequence of a novel α-CoV strain detected in rectal swab samples of Miniopterus fuliginosus bats from a colony in the Wavul Galge cave (Koslanda, Sri Lanka). The novel strain is highly similar to Miniopterus bat coronavirus 1, an α-CoV located in the subgenus of Minunacoviruses. Phylogenetic reconstruction revealed a high identity of the novel strain to other α-CoVs derived from Miniopterus bats, while human-pathogenic α-CoV strains like HCoV-229E and HCoV-NL63 were more distantly related. Comparison with selected bat-related and human-pathogenic strains of the β-CoV genus showed low identities of ~40%. Analyses of the different genes on nucleotide and amino acid level revealed that the non-structural ORF1a/1b are more conserved among α-CoVs and β-CoVs, while there are higher variations in the structural proteins known to be important for host specificity. The novel strain was named batCoV/MinFul/2018/SriLanka and had a prevalence of 50% (66/130) in rectal swab samples and 58% (61/104) in feces samples that were collected from Miniopterus bats in Wavul Galge cave. Based on the differences between strain batCoV/MinFul/2018/SriLanka and human-pathogenic α-CoVs and β‑CoVs, we conclude that there is a rather low transmission risk to humans. Further studies in the Wavul Galge cave and at other locations in Sri Lanka will give more detailed information about the prevalence of this virus.

Bats are known to be potential reservoirs of numerous human-pathogenic viruses. They have been identified as natural hosts for coronaviruses, causing Severe Acute Respiratory Syndrome (SARS) in humans. Since the emergence of SARS-CoV-2 in 2019 interest in the prevalence of coronaviruses in bats was newly raised. In this study we investigated different bat species living in a sympatric colony in the Wavul Galge cave (Koslanda, Sri Lanka). In three field sessions (in 2018 and 2019), 395 bats were captured (Miniopterus, Rousettus, Hipposideros and Rhinolophus spp.) and either rectal swabs or fecal samples were collected. From these overall 396 rectal swab and fecal samples, the screening for coronaviruses with nested PCR resulted in 33 positive samples, 31 of which originated from Miniopterus fuliginosus and two from Rousettus leschenaultii. Sanger sequencing and phylogenetic analysis of the obtained 384-nt fragment of the RNA-dependent RNA polymerase revealed that the examined M. fuliginosus bats excrete alphacoronaviruses and the examined R. leschenaultii bats excrete betacoronaviruses. Despite the sympatric roosting habitat, the coronaviruses showed host specificity and seemed to be limited to one species. Our results represent an important basis to better understand the prevalence of coronaviruses in Sri Lankan bats and may provide a basis for pursuing studies on particular bat species of interest.

Bats are known as typical reservoirs for a number of viruses, including viruses of the family Paramyxoviridae. Representatives of the subfamily Orthoparamyxovirinae are distributed worldwide and can cause mild to fatal diseases when infecting humans. The research on Paramyxoviruses (PMVs) from different bat hosts all over the world aims to understand the diversity, evolution and distribution of these viruses and to assess their zoonotic potential. A high number of yet unclassified PMVs from bats are recorded. In our study, we investigated bat species from the families Rhinolophidae, Hipposiderae, Pteropodidae and Miniopteridae that are roosting sympatrically in the Wavul Galge cave (Koslanda, Sri Lanka). The sampling at three time points (March and July 2018; January 2019) and screening for PMVs with a generic PCR show the presence of different novel PMVs in 10 urine samples collected from Miniopterus fuliginosus. Sequence analysis revealed a high similarity of the novel strains among each other and to other unclassified PMVs collected from Miniopterus bats. In this study, we present the first detection of PMVs in Sri Lanka and the presence of PMVs in the bat species M. fuliginosus for the first time.

Bats are described as the natural reservoir host for a wide range of viruses. Although an increasing number of bat-associated, potentially human pathogenic viruses were discovered in the past, the full picture of the bat viromes is not explored yet. In this study, the virome composition of Miniopterus phillipsi bats (formerly known as Miniopterus fuliginosus bats in Sri Lanka) inhabiting the Wavul Galge cave, Sri Lanka, was analyzed. To assess different possible excretion routes, oral swabs, feces and urine were collected and analyzed individually by using metagenomic NGS. The data obtained was further evaluated by using phylogenetic reconstructions, whereby a special focus was set on RNA viruses that are typically associated with bats. Two different alphacoronavirus strains were detected in feces and urine samples. Furthermore, a paramyxovirus was detected in urine samples. Sequences related to Picornaviridae, Iflaviridae, unclassified Riboviria and Astroviridae were identified in feces samples and further sequences related to Astroviridae in urine samples. No viruses were detected in oral swab samples. The comparative virome analysis in this study revealed a diversity in the virome composition between the collected sample types which also represent different potential shedding routes for the detected viruses. At the same time, several novel viruses represent first reports of these pathogens from bats in Sri Lanka. The detection of two different coronaviruses in the samples indicates the potential general persistence of this virus species in M. phillipsi bats. Based on phylogenetics, the identified viruses are closely related to bat-associated viruses with comparably low estimation of human pathogenic potential. In further studies, the seasonal variation of the virome will be analyzed to identify possible shedding patterns for particular viruses.

Bats are important contributors to the global ecosystems; at the same time, they are known to be a natural reservoir host for a number of human pathogenic viruses. These and many other unique features make them an interdisciplinary research object in the context of One Health, comprising zoology, ecology, virology, microbiology, molecular biology, immunology and public health issues. Performing field studies for bat research often aims to cover several of these topics and requires the combination of specific expertise in different fields. We carried out three individual field studies in Wavul Galge cave (Koslanda, Sri Lanka), where several bat species roost sympatrically. The main goals were to study the bat colony for ecological aspects and to sample bats for virological and molecular biological analyses. In the course of the field studies, we optimized the sampling procedure regarding safety aspects, a preferably low impact on the captured bats and an improved output of high-quality samples for further analysis. Different sampling methods and procedures were compared in order to establish a suitable strategy for frequent sampling and monitoring of these bats. In the present case study, we report on this process of optimizing our field work and provide suggestions for bat sampling methods that cause comparably less stress for the captured animals. We also report on constraints and obstacles encountered during the practical implementation and possible measures to overcome these. With these practical experiences, we hope to give support to other interdisciplinary research teams preparing for bat field work. Furthermore, we emphasize the need for the respectful treatment of the animals and minimized disturbance of their natural habitat when carrying out 50 sustainable bat research.