Isolation and identification of a natural reassortant mammalian orthoreovirus from least horseshoe bat in China.

Background Mammalian orthoreoviruses (MRVs) have a wide geographic distribution and can infect virtually all mammals. Infections in humans may be either symptomatic or asymptomatic. This study describes the isolation and identification of a natural reassortant MRV from least horseshoe bats (Rhinolophus pusillu) in China, referred to as RpMRV-YN2012. Methods and Results The RpMRV-YN2012 was obtained from urine samples of Rhinolophus pusillus by cell culture. Negative-staining electron microscopy revealed that RpMRV-YN2012 was a non-enveloped icosahedral virus with ~75 nm in diameter. Polyacrylamide gel electrophoresis (PAGE) migration patterns of the genome segments showed that RpMRV-YN2012 contained 10 segments in a 3:3:4 arrangement. The whole genome sequence of RpMRV2012 was determined. The consensus terminal sequences of all segments of 5’-GCUAh…yUCAUC-3’ (h = A, U or C; y = C or U) were similar to the MRV species within the genus Orthoreovirus. Its evolution and evidence of genetic reassortment were analyzed by sequence comparison and phylogenetic analysis. The results showed that RpMRV-YN2012 is a novel serotype 2 MRV that may have originated from reassortment among bat, human, and/or pig MRV strains which associated with diarrhea, acute gastroenteritis and necrotizing encephalopathy in animals and humans. Conclusions RpMRV-YN2012 is a novel bat reassortant MRV, which may have resulted from a reassortment involving MRVs known to infect humans and animals. It is necessary to identify whether RpMRV-YN2012 is associated with diarrhea, acute gastroenteritis and necrotizing encephalopathy in clinical patients. In addition, we should carefully monitor its evolution and virulence in real time.