Complete Genome Characterization of Recent and Ancient Belgian Pig Group A Rotaviruses and Assessment of Their Evolutionary Relationship with Human Rotaviruses

Abstract

Group) Belgian pig RVA strains and of all completely characterized pig RVAs from around the globe. In contrast to the large diversity of genotypes found for the outer capsid proteins VP4 and VP7, a relatively conserved genotype constellation (I5-R1-C1-M1-A8-N1-T7-E1-H1) was found for the other 9 genes in most pig RVA strains. VP1, VP2, VP3, NSP2, NSP4, and NSP5 genes of porcine RVAs belonged to genotype 1, which is shared with human Wa-like RVAs. However, for most of these gene segments, pig strains clustered distantly from human Wa-like RVAs, indicating that viruses from both species have entered different evolutionary paths. However, VP1, VP2, and NSP3 genes of some archival human strains were moderately related to pig strains. Phylogenetic analysis of the VP6, NSP1, and NSP3 genes, as well as amino acid analysis of the antigenic regions of VP7, further confirmed this evolutionary segregation. The present results also indicate that the species barrier is less strict for pig P[6] strains but that chances for successful spread of these strains in the human population are hampered by the better adaptation of pig RVAs to pig enterocytes. However, future surveillance of pig and human RVA strains is warranted. IMPORTANCERotaviruses are an important cause of diarrhea in many species, including pigs and humans. Our understanding of the evolutionary relationship between rotaviruses from both species is limited by the lack of genomic data on pig strains. In this study, recent and ancient Belgian pig rotavirus isolates were sequenced, and their evolutionary relationship with human Wa-like strains was investigated. Our data show that Wa-like human and pig strains have entered different evolutionary paths. Our data indicate that pig P[6] strains form the most considerable risk for interspecies transmission to humans. However, efficient spread of pig strains in the human population is most likely hampered by the adaptation of some crucial viral proteins to the cellular machinery of pig enterocytes. These data allow a better understanding of the risk for direct interspecies transmission events and the emergence of pig rotaviruses or pig-human reassortants in the human population. E nteric diseases in pigs are mostly encountered during two critical time points: the suckling period and after weaning. Several pathogens are frequently involved in the pathogenesis of piglet diarrhea, including rotavirus, porcine epidemic diarrhea virus, transmissible gastroenteritis virus, Escherichia coli, Clostridium perfringens, Salmonella spp., Brachyspira spp., and Isospora suis. Furthermore, coinfections between different rotaviruses and other pathogens can be found frequently in diarrheic pigs (1).Rotaviruses are a major cause of diarrhea in many species, including pigs and humans. Five official rotavirus species (A to E) and 3 tentative species (F to H) have been established based on nucleotide similarities of the VP6-encoding genes (2). Species A, B, and C are frequently isolated from feces of diarrheic and nondiarrheic pigs, wh...

Whole-genomic analysis of 12 porcine group A rotaviruses isolated from symptomatic piglets in Brazil during the years of 2012–2013

“…In addition, according to da , the high frequency of detection of G5 strains in humans in Brazil may be been linked to porcine-human strain reassortment due to mixed infections. Similar findings were also described recently by Theuns et al who demonstrated a phylogenetic distinction between the genes of porcine and human strains in different subclusters of the tree (Theuns et al, 2015). In this study, the highest relatedness between the VP7-coding gene of porcine and human RVAs was demonstrated for the G9 genotype.…”

“…Reinforcing these results, Theuns et al (2015) described that the VP7-coding genes of contemporary porcine and human G9 strains seem to be much more related to each other than are those of other VP7 genotypes. The close relationship of the VP7-coding genes of porcine and human G9 strains was also demonstrated by the limited number of mutations presented between antigenic regions of the encoded proteins.…”

“…We found that these RVAs exhibit G3, G5, G9, and G11 genotypes, associated with P[6], P[13], and P[23] genotypes and an internal gene constellation of I5-R1-C1-M1-A8-N1-T1/T7-E1-H1. Most of the strains sequenced in this study were found to be G9P[23], a G/P-genotype combination that has been reportedly rising in porcine populations (Okitsu et al, 2013;Theuns et al, 2015;Tonietti et al, 2013).…”

“…Analyses of porcine strains demonstrated a higher level of genetic diversity than what was found for strains isolated from humans (Matthijnssens et al, 2010a,b). Moreover, G9 porcine strains have been shown to exhibit diverse P-genotypes P[6], P[7], P[13], and P[23]) (Kim et al, 2010Martel-Paradis et al, 2013;Theuns et al, 2015;Tonietti et al, 2013).…”

Comparative In Vitro and In Vivo Studies of Porcine Rotavirus G9P[13] and Human Rotavirus Wa G1P[8]

“…Therefore, the HRV-like G9 VP7 genotype of this PRV G9P [13] strain likely emerged from reassortment events (56,57). Recent studies confirmed that some emerging G9 RVs in humans were phylogenetically more similar to PRVs than to earlier human G9 genotypes, suggesting that PRVs are probable sources of heterologous RV infections in humans (22,25).…”