SARS coronavirus (SARS-CoV), the causative agent of the large SARS outbreak in 2003, originated in bats. Many SARS-like coronaviruses (SL-CoVs) have been detected in bats, particularly those that reside in China, Europe, and Africa. To further understand the evolutionary relationship between SARS-CoV and its reservoirs, 334 bats were collected from Zhoushan city, Zhejiang province, China, between 2015 and 2017. PCR amplification of the conserved coronaviral protein RdRp detected coronaviruses in 26.65% of bats belonging to this region, and this number was influenced by seasonal changes. Full genomic analyses of the two new SL-CoVs from Zhoushan (ZXC21 and ZC45) showed that their genomes were 29,732 nucleotides (nt) and 29,802 nt in length, respectively, with 13 open reading frames (ORFs). These results revealed 81% shared nucleotide identity with human/civet SARS CoVs, which was more distant than that observed previously for bat SL-CoVs in China. Importantly, using pathogenic tests, we found that the virus can reproduce and cause disease in suckling rats, and further studies showed that the virus-like particles can be observed in the brains of suckling rats by electron microscopy. Thus, this study increased our understanding of the genetic diversity of the SL-CoVs carried by bats and also provided a new perspective to study the possibility of cross-species transmission of SL-CoVs using suckling rats as an animal model.

Since an outbreak of severe acute respiratory syndrome (SARS) was averted in 2004, many novel coronaviruses have been recognized from different species, including humans. Bats have provided the most diverse assemblages of coronaviruses, suggesting that they may be the natural reservoir. Continued virological surveillance has proven to be the best way to avert this infectious disease at the source. Here we provide the first description of a previously unidentified coronavirus lineage detected from wild Asian leopard cats (Prionailurus bengalensis) and Chinese ferret badgers (Melogale moschata) during virological surveillance in southern China. Partial genome analysis revealed a typical coronavirus genome but with a unique putative accessory gene organization. Phylogenetic analyses revealed that the envelope, membrane, and nucleoprotein structural proteins and the two conserved replicase domains, putative RNA-dependent RNA polymerase and RNA helicase, of these novel coronaviruses were most closely related to those of group 3 coronaviruses identified from birds, while the spike protein gene was most closely related to that of group 1 coronaviruses from mammals. However, these viruses always fell into an outgroup phylogenetic relationship with respect to other coronaviruses and had low amino acid similarity to all known coronavirus groups, indicating that they diverged early in the evolutionary history of coronaviruses. These results suggest that these viruses may represent a previously unrecognized evolutionary pathway, or possibly an unidentified coronavirus group. This study demonstrates the importance of systematic virological surveillance in market animals for understanding the evolution and emergence of viruses with infectious potential.Since the severe acute respiratory syndrome (SARS) outbreak in early 2003, many new viruses of the family Coronaviridae have been identified in diverse host species, including birds, humans, and other mammals (7, 12-14, 18, 25, 27, 28, 29). Of these hosts, bats have provided the highest genetic diversity of novel coronaviruses (CoVs) (23,29). Analyses of the genomic organization and phylogenetic relationships of CoVs from bats and other host species indicate that bats are the likely natural reservoirs for all known CoVs from other hosts (23,26). This research also suggests that CoVs resident in bats may be introduced into other animals and subsequently become established in these hosts.Interspecies transmission of CoV from its natural reservoir to another species might result in disease outbreaks in naive hosts. The emerging pathway of SARS CoV in humans and market civets is an example of this (4, 5). Accumulated information has demonstrated that many SARS-like CoVs are harbored in bat species (12,13,23). However, the cross homologies between civet and human SARS CoV and bat SARS-like CoVs are still relatively low (about 92%), even in the most conserved regions of the replicase gene (13). Phylogenetic analyses and divergence dates of these CoVs indicate that the likely interme...

Bats have been shown as important mammal resevoirs to carry a variety of zoonotic pathogens. To analyze pathogenic species in bats from southeast coastal regions of China, we performed metagenomic sequencing technology for high throughput sequencing of six sentinels from southeast coastal area of China. We obtained 5,990,261 high quality reads from intestine and lung tissue of 235 bats, including 2,975,371 assembled sequences. 631,490 reads predicted overlapping sequences for the open reading frame (ORF), which accounts for 2.37% of all the sequences (15,012/631,490). Further, the acquired virus sequences were classified into 25 viral families, including 16 vertebrate viruses, four plant viruses and five insect viruses. All bat samples were screened by specific PCR and phylogenetic analysis. Using these techniques, we discovered many novel bat viruses and some bat viruses closely-related to known human/animal pathogens, including coronavirus, norovirus, adenovirus, bocavirus, astrovirus, and circovirus. In summary, this study extended our understanding of bats as the viral reservoirs. Additionally, it also provides a basis for furher studying the transmission of viruses from bats to humans.

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