Picobirnavirus infections: viral persistence and zoonotic potential

Abstract

Picobirnaviruses (PBVs) are small, non-enveloped, bisegmented double-stranded RNA genomic viruses of vertebrate hosts. Since their discovery in the late 1980s in clinical specimens from outbreaks of acute gastroenteritis in children, significant efforts have been made to investigate the role of PBV in diarrheic diseases. PBV has been detected in sporadic episodes of diarrhea as sole pathogen or coinfection as well as in outbreaks of acute gastroenteritis and in immunocompromised patients with diarrhea. However, PBV is frequently detected in non-diarrheic healthy hosts, and prolonged shedding has been observed in some individuals. Of interest, similar patterns of PBV infection have also been observed in pigs and other animal hosts. The increasing amount of PBV sequence data gathered from molecular epidemiological studies has evidenced a great sequence diversity of PBVs in various hosts and environmental samples. Importantly, evidence has been found for genetic relatedness between human and animal PBV strains, suggesting extant crossing points in the ecology and evolution of heterologous PBV strains. At present, no cell culture and animal model exists for PBVs. Well-structured epidemiological studies are still the only alternative to demonstrate the potential etiological role of PBVs in acute gastroenteritis or other diseases. This review aims to analyze the public health aspects of PBV infection, especially its possible association with zoonosis.

Animal Picobirnavirus

“…Thus, the probable role of PBV as either a primary diarrhoeal agent in immunocompetent children [6,7], a potential pathogen in immunocompromised individuals [38,39,44] or an innocuous virus in the intestine remains elusive and needs to be investigated despite the numerous reports of the presence of PBV in fecal samples of various hosts species; our current knowledge of their biology, etiology, pathogenicity or their transmission characteristics remains subtle [15,32,33,57], mainly because of their non-cultivable status (in vivo and in vitro) that is, the absence of a cell culture system and suitable animal model for propagating the virus. Further studies in gnotobiotic animals may shed light on PBV pathogenic potential [15].…”

“…As a consequence of the limited diagnostic methodology available, PBV is only detected in research laboratories with specific interest in this agent or during rotavirus surveillance by PAGE assay. Therefore, what is known about the epidemiology of PBV reflects more the ease of laboratory detection than the true epidemiology of infection with the agent itself [32,33,40]. In many laboratories both in developed and developing nations, for the purpose of routine surveillance, ELISA technique was the method of choice for detection of Group A rotaviruses from bulk or whole-stool specimen obtained from children with acute gastroenteritis as per the recommendations in the WHO generic protocol for hospital and community-based surveillance [85] as it has high sensitivity, and has a built-in control for non-specific reaction, and serves as a reliable diagnostic tool for virus detection for a large number of samples in a cost-effective way.…”

Detection and Molecular Characterization of Porcine Picobirnavirus in Feces of Domestic Pigs from Kolkata, India

“…PBVs were detected from immunocompromised patients [24] in which implied to be ''opportunistic pathogens'' and have also been detected from asymptomatic hosts [11]. The question whether PBV is an 'innocuous agent' of the intestine remains to be investigated [2,7,19,31,35].…”

“…PBVs are known to cause chronic diarrhoea with prolonged shedding of the virus in humans [24] and various animals [30] besides frequent infections among piglets [5,29]. Moreover, the presence of genogroup I PBVs in humans and different animals, rodents and reptiles, suggests that any specific genogroup is not restricted to specific host [2,3,5,12,16,19,31].…”

“…The question if PBV is transmitted directly through contact between different host species or by using the same sources (e.g. Water) is an objective of future studies [19].…”