|Ng, Terry -|
|Delwart, Eric -|
|Pogranichniy, Roman -|
|Kehrli Jr, Marcus|
Submitted to: Archives of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 19, 2013
Publication Date: October 1, 2013
Citation: Cheung, A.K., Ng, T.F., Lager, K.M., Bayles, D.O., Alt, D.P., Delwart, E.L., Pogranichniy, R.M., Kehrli, Jr., M.E. 2013. A divergent clade of circular single-stranded DNA viruses from pig feces. Archives of Virology. 158(10):2157-2162. Interpretive Summary: Infectious swine diseases are caused by a variety of viruses and bacteria. Traditional methods to detect these infectious agents depended on isolation of the virus or bacteria, a process that could be costly and time consuming. Over the last 20 years methods have been developed that can detect nucleic acids (DNA or RNA), the genetic material of bacteria and viruses, allowing detection of infectious agents without the need to culture. This technology has led to the discovery of agents that could not be cultured, and thus were previously unknown. Advances in this nucleic acid technology has enabled a faster and more broad approach to discovering viruses and bacteria that cannot yet be cultured. This paper describes the application of these new techniques to detect novel viruses in U.S pigs that are similar to recently detected swine viruses in other parts of the world. The viruses are related to viruses detected in chimpanzees and cattle and these viruses may be classified as a new group. To date, there is no association between this group of viruses and disease suggesting they may be part of a growing list of viruses that infect animals with no known consequences. However, additional studies are warranted to determine the prevalence of these viruses in swine, and investigate further their disease causing potential.
Technical Abstract: Using metagenomics and molecular cloning methods, we characterized five novel small circular viral genomes from pig feces distantly related to chimpanzee and porcine stool-associated circular viruses, (ChiSCV and PoSCV1). Phylogenetic analysis placed these viruses into a new, highly divergent, clade of this rapidly growing new viral family. This new clade of viruses, provisionally named porcine stool-associated circular virus 2 and 3 (PoSCV2 and PoSCV3), encode a stem-loop structure (presumably the origin of DNA replication) in the small intergenic region and a replication initiator protein commonly found in other biological systems that replicate their genomes via the rolling-circle mechanism. Furthermore, these viruses also exhibit three additional overlapping open-reading frames in the large intergenic region between the capsid and replicase genes.