Global Distribution of Coronaviruses among Bat Populations detected using Molecular techniques, A Systematic Review
Surveillance of bat coronaviruses (CoVs) is of public health importance, as accumulating evidence suggests that bats are hosts of the three significant pandemic viruses, namely Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and SARS-CoV-2. Studies focused on identifying different species of bat CoVs may have information cardinal for effective prevention and control of emerging zoonotic diseases. We conducted a systematic review using selected keywords (Surveillance, detection, identification, discovery, isolation, characterization, molecular methods, and Bat coronaviruses) to evaluate molecular studies on CoVs in bats. A total of 790 articles were found using the advanced search strategy of the PubMed database. Following the selection criteria, a total of 127 articles were finally chosen for full-text evaluation. Out of the total of 54 countries examined, China emerged as the country with the highest number of studies, accounting for 26% (n = 33). The sample categories consisted of faecal, urine, guano, blood, tissues, oral, and rectal swabs. The molecular detection approaches included polymerase chain reaction (PCR)-based techniques using species-specific, genus-specific, or broad-range primers. Approximately 94.5% (n = 120) of studies used PCR assays that amplified the partial RdRp gene of length ranging from 123 to 440 bp, followed by amplicon sequencing using either Sanger or next-generation sequencing technologies. Full genome sequencing was only performed in approximately 33.9% (n = 43), with metagenomics approaches being used in 15.7% (n = 20) of the studies. The higher positivity rate of bat CoVs were detected in Asia. Globally, the most predominant bat species which tested positive for CoVs were Rhinolophus, Myotis, Miniopterus, Scotophilus, Eidolon, Chaerephon, Hipposideros, and Desmodus. Continuous bat coronavirus surveillance using molecular methods and full genome sequencing is of utmost importance in detecting and characterizing viruses at molecular level and establishing the genetic diversity of new and circulating viruses.