Picobirnaviruses in animals: a review

Abstract

Picobirnaviruses (PBVs) are small non enveloped viruses with bi-segmented ds RNA. They have been observed in a wide variety of vertebrates, including mammals and birds with or without diarrhoea, as well as in sewage samples since its discovery (1988). The source of the viruses is uncertain. True hosts of PBVs and their role as primary pathogens or secondary opportunistic agents or innocuous viruses in the gut remains alien. The mechanisms by which they play a role in pathogenicity are still unclear based on the fact that they can be found in both symptomatic and asymptomatic cases. There is a need to determine their tropism since they have not only been associated with viral gastroenteritis but also been reported in the respiratory tracts of pigs. As zoonotic agents with diverse hosts, the importance of epidemiological and surveillance studies cannot be overstated. The segmented genome of PBV might pose a serious public health issue because of the possibility of continuous genetic reassortment. Aware of the growing attention being given to emerging RNA viruses, we reviewed the current knowledge on PBVs and described the current status of PBVs in animals.

Keywords: Bi-segmented RNA; Emerging viruses; Opportunistic; Picobirnavirus; Prokaryotic virus; Zoonotic potential.

Fig. 1

Organization of genome of human PBV genogroup-I strain Hy005102. A There are three putative open reading frames (ORF) in gene segment-1 (GenBank accession number AB186897) of PBV strain Hy005102: ORF1, ORF2 and ORF3. The ORF3 codes for a precursor of the viral capsid protein (GenBank accession number AB186897). B Gene segment-2 of PBV strain Hy005102 contains a single ORF that encodes the viral RNA-dependent RNA polymerase (RdRp) (GenBank accession number AB186898) [13]