Detection and molecular characterization of porcine picobirnavirus in feces of domestic pigs from kolkata, India

Abstract

Picobirnaviruses (PBVs) are small, non-enveloped, 35-41 nm virion with bisegmented double-stranded RNA genome. PBVs are widespread and were detected in feces of humans and a wide variety of animals. Domestic pig, one of the ubiquitous farm animal reported incessant association with a variety of viral zoonoses. The objective of our study is to find out the incidence of PBV infection in healthy domestic pigs. The study was conducted by collecting feces of healthy/asymptomatic pigs from a piggery located in an urban slum at Kolkata, India to detect PBV infections. All the 11 fecal samples were tested by polyacrylamide gel electrophoresis and reverse transcription-polymerase chain reaction assay. In this study, we report the first incidence of detection and molecular characterization of porcine PBV (BG-Por-2/2010 and BG-Por-7/2010) in feces of domestic pigs from India using the human PBV genogroup I specific primer pair: PicoB25(+) and PicoB43(-). Sequence comparison and phylogenetic analysis of partial RNA-dependent RNA polymerase gene of genome segment 2 revealed genetic relatedness to hitherto reported porcine, murine and human genogroup I PBVs from different geographical regions. This warrants a stringent global surveillance to study the potential zoonotic and emerging PBV infections.

Keywords: Domestic pigs; Genogroup I PBVs; Genomic diversity; Picobirnaviruses (PBVs); Zoonoses.

Fig. 1

Phylogenetic tree showing the porcine PBV strain (genogroup I PBV/Pig/India/BG-Por-2/2010) with cognate stretch of hitherto reported human, porcine, bovine, canine, murine, avian, serpentine and environmental genogroup I PBV strains based on partial amino acid sequence [56 amino acids (aa)] partial RdRp gene of genomic segment 2. The phylogenetic tree was constructed by the neighbor-joining method using the MEGA software (Version 4.1). Phylogenetic distances were measured by the Kimura two-parameter model, and the tree was statistically supported by bootstrapping with 1,000 replicates. The genogroup I porcine PBV strain BG-Por-2 is denoted with a filled circle symbol. The tree was rooted with cognate stretch of gene segment 2 of genogroup II prototype strain Hu/4-GA-91 (USA) defined as the outgroup strain. Bar 0.2 substitutions per nucleotide. Abbreviations: Hu human, Bo bovine, Po porcine, Eq equine, Av avian, Mu murine, Env environmental, ARG Argentina, BRA Brazil, Hun Hungary, Thai Thailand, USA United States of America, Ven Venezuela