Characterization of rotavirus possessing a DS-1-like VP3 gene from pigs in Brazil: Evidence for zooanthroponotic transmission.

Porcine group A rotavirus (RVA) strains SUI15A and SUI24A are suggested to have VP3 genes of human origin possessing DS-1-like backbone. The aim of the present study was to analyse the genome of two strains (SUI15A and SUI24A) and understand the evolution of a rare human-like M2 genotype in pigs. On partial genomic analysis, strains SUI24A (G3-P[13]-I5-R1-C1-M2-A8-N1-T7-E1-H1) and SUI15A (G3-P[x]-Ix-R1-C1-M2-Ax-Nx-T7-E1-H1) were found to have VP3 gene RVA different from those of typical porcine RVA strains described in Brazil and worldwide. This genotypic constellation was a novel constellation that has not been reported previously in both humans and pigs. Furthermore, on phylogenetic analysis, VP3 gene of strains appeared to be of human origin. Therefore, suggested to have evidence for human-to-porcine zooanthroponotic transmission.

High prevalence of G12P[8] rotavirus strains in Rio Branco, Acre, Western Amazon, in the post-rotavirus vaccine introduction period.

The present study aimed to provide a molecular characterization of circulating rotavirus (RVA) strains in Rio Branco, Acre, in the post-rotavirus vaccination period, particularly with regard to the emerging, increasingly prevalent G12P[8] genotype. A total of 488 fecal specimens from diarrheic and non-diarrheic children were obtained between January and December 2012. RVA detection was initially performed using enzyme-linked immunosorbent assay (ELISA) method, followed by reverse-transcription polymerase chain reaction (RT-PCR) using specific primers. RVA was detected in 18.3% (44/241) of the children with acute diarrhea and in 1.2% (3/247) of the non-diarrheic children (P < 0.001), with overall RVA-positivity of 9.6% (47/488). The most common genotype was G2P[4] with 43.2% (19/44) of the diarrheic cases, followed by G12P[8] (27.3%, 12/44), G3P[6] (18.2%, 8/44), G3P[8] (4.5%, 2/44), and G12P[6] (2.3%, 1/44). G12 samples belonged to lineage III and were from children aged 4-52 months. All of these children had acute diarrhea associated with fever (83.3%, 10/12) and vomiting (66.7%, 8/12). Most of the cases occurred in August (58.3%, 7/12), 75% (9/12) of which having received the full vaccination scheme with Rotarix™. For the first time G12 was reported at relative high prevalence in Brazil. Our findings warrant further monitoring studies on the molecular characterization of circulating RVA strains after rotavirus vaccine introduction in Brazil and elsewhere, since the occurrence of either unusual our emerging genotypes may pose a challenge to vaccination strategies.