Porcine sapoviruses: Pathogenesis, epidemiology, genetic diversity, and diagnosis

Abstract

The first porcine Sapovirus (SaV) Cowden strain was discovered in 1980. To date, eight genogroups (GIII, V-IX) and three genogroups (GIII, GV, and GVI) of porcine SaVs have been detected from domestic pigs worldwide and wild boars in Japan, respectively based on the capsid sequences. Although GIII Cowden strain replicated in the villous epithelial cells and caused intestinal lesions in the proximal small intestines (mainly in duodenal and less in jejunum), leading to mild to severe diarrhea, in the orally inoculated neonatal gnotobiotic pigs, the significance of porcine SaVs in different ages of pigs with diarrhea in the field is still undetermined. This is due to two reasons: 1) similar prevalence of porcine SaVs was detected in diarrheic and non-diarrheic pigs; and 2) coinfection of porcine SaVs with other enteric pathogens is common in pigs. Diagnosis of porcine SaV infection is mainly based on the detection of viral nucleic acids using reverse transcription (RT)-PCR and sequencing. Much is unknown about these genetically diverse viruses to understand their role in pig health and to evaluate whether vaccines are needed to prevent SaV infection.

Exploring the Cause of Diarrhoea and Poor Growth in 8–11-Week-Old Pigs from an Australian Pig Herd Using Metagenomic Sequencing

“…Taken together, the association of these several bacteria and viruses with disease pathogenesis as shown by various studies fits well with the clinical signs of disease observed in the herd in this study and could potentially support the role of these identified pathogens for disease pathogenesis [ 26 , 48 , 94 , 133 , 134 ] in which the viral infection might have followed the bacterial infection or vice versa. Despite being a relatively expensive and time intensive technology, in particular for data analysis of even a single sample, NGS has become a powerful tool and has demonstrated numerous advantages over conventional targeted detection technologies by detecting co-infections, novel or unique and emerging pathogens for which detection methods do not exist.…”

Genetic characterization of porcine sapoviruses identified from pigs during a diarrhoea outbreak in Iowa, 2019

“…Among them, 17 genogroups (GII, GIII and GV–GXIX) have been identified in animals and four (GI, GII, GIV and GV) in humans (Scheuer et al., 2013) with genogroups II (GII) and V (GV) detected in both animals and humans (Oka et al., 2015). Thus far, at least eight genogroups (GIII, GV, GVI, GVII, GVIII, GIX, GX, and GXI) of SaVs have been associated with pigs (Nagai et al., 2020; Oka et al., 2016; Scheuer et al., 2013). Our recent genomic characterization study reveals that highly divergent porcine SaV strains co‐circulate in the field in the United States (Wang et al., 2020).…”

Detection of Sapovirus in Brazilian Pig Farms

“…Porcine SaV has been identified on every continent except Oceania (Reuter et al, 2010), presenting a wide range of frequency and genotypes. In most of these studies, no direct association was observed between diarrhea and SaV (Reuter et al, 2010;Salamunova et al, 2018;Nagai et al, 2020).…”

“…Although the viral classification is based on the VP1 gene, Schuffenecker et al (2001) showed that, when comparing different strains of SaVs in the RdRp gene, the 3'ORF and ORF capsid overlapping sequences and 3'UTR (untranslated region) demonstrate the same classification. With this, it is possible to verify that most of the molecular detection studies use the RdRp gene and/or capsid junction region because it presents a more conserved region (Nagai et al, 2020).…”

“…Molecular analyzes (genogroup and genotype) are important for understanding the dynamics and evolution of SaVs, given their remarkable genetic variability (Oka et al, 2016). Although transmission of the same genotype between humans and pigs has not been reported, it is possible to identify genetic proximity mainly in the GV genogroup (pig GV.3 / GV.5 and human GV.1-2) (Nagai et al, 2020).…”