G12 rotavirus has not been detected anywhere in the world since the first detection of a human strain, L26 (G12, P1B[4]), in the Philippines in 1990. In this study, we isolated a human rotavirus (strain T152) with a VP7 of G12 specificity from the stool of an 11-month-old diarrheic patient in Thailand. The strain T152 exhibited a long RNA pattern and subgroup I specificity. In the comparison of the nucleotide and amino acid sequences of the VP7 gene of strain T152 with those of rotaviruses with different G type specificities, strain T152 showed the highest identity, 90.9 and 93.9%, respectively, to G12 prototype strain L26. In contrast, the VP4 gene of strain T152 showed the highest identity with P[9] specificity of human strains K8 and AU-1 and feline strains Cat2 and FRV-1, with homologies of 89.3 to 90.6% at the nucleotide level and 93.9 to 95.6% at the amino acid level. Thus, strain T152 was found to be a natural reassortant strain with G12 and P[9] specificities.Rotavirus is the major cause of acute gastroenteritis in infants of animals and humans. In developing countries, rotavirus infection results in high mortality, and an annual death rate of 800,000 persons has been estimated (6). Furthermore, in developed countries, rotavirus infection is a cause of high morbidity. However, to date no vaccine has been successful. Rotavirus VP7 and VP4 have independent serotype specificities of the G serotype and P serotype, respectively. A total of 14 G serotypes have been reported. Among them, 10 G serotypes have been detected in humans. G1 to G4 are the major G serotypes, and G5, G6, G8 to G10, and G12 are minor or unusual ones (2, 6). In contrast, 21 P genotypes have been recognized, and at least 10 P genotypes have been detected in humans. Recently, a number of strains with an unusual G or P type and a rare combination of G and P types have been detected in human rotaviruses worldwide (1, 3, 10-12, 16, 17, 25-27).G12 was first detected in stool specimens collected from diarrheic children under 2 years of age between December 1987 and February 1988 in the Philippines (20, 27). In 40 rotavirus-positive stool specimens, 20 samples showed subgroup I and long RNA profile (7). Four samples were adapted to cell culture, and at least two (L26 and L27) of them were found to have G12 and P1B[4] specificities by serological and sequence analyses of their VP4 and VP7 (20,27). Since then, however, no further report on the detection of G12 in humans or animals has been presented, although extensive surveys on the G serotype distribution worldwide have been conducted. In this study, we isolated a human rotavirus with G12 and P[9] specificities in Thailand. MATERIALS AND METHODSStool specimens. A total of 405 stool specimens were collected from diarrheic children in a hospital of the Queen Sirikit National Institute of Child Health, Thailand, between 1998 and 1999. An approximately 10% (wt/vol) stool suspension was prepared in phosphate-buffered saline. For virus isolation in MA-104 cells in roller tube culture, each stool extr...

No abstract

A bovine rotavirus, NGRBg8, isolated from the feces of a calf with diarrhea in Nigeria was characterized by reverse transcription-PCR, nucleotide sequence analysis, and Northern blot hybridization. The nucleotide sequence of the VP7 gene of the strain was most closely related to that of a Nigerian human G8-serotype strain, HMG035 (99.9%). The NSP1 gene of strain NGRBg8 is highly related (99.4%) to that of a Thai G8 bovine strain, A5-10. Northern blot hybridization revealed a high overall genomic relatedness of bovine strain NGRBg8 with human strain HMG035; all 11 RNA segments hybridized to each other. Thus, the results show the close relationship between G8 bovine and human rotaviruses in Nigeria.

No abstract

G12 rotaviruses are emerging rotavirus strains causing severe diarrhea in infants and young children worldwide. However, the whole genomes of only a few G12 strains have been fully sequenced and analyzed. In this study, we sequenced and characterized the complete genomes of six G12 strains (RVA/Human-tc/MMR/A14/2011/G12P[8], RVA/Human-tc/MMR/A23/2011/G12P[6], RVA/Human-tc/MMR/A25/2011/G12P[8], RVA/Human-tc/MMR/P02/2011/G12P[8], RVA/Human-tc/MMR/P39/2011/G12P[8], and RVA/Human-tc/MMR/P43/2011/G12P[8]) detected in six stool samples from children with acute gastroenteritis in Myanmar. On whole genomic analysis, all six Myanmarese G12 strains were found to have a Wa-like genetic backbone: G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 for strains A14, A25, P02, P39, and P43, and G12-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1 for strain A23. Phylogenetic analysis showed that most genes of the six strains examined in this study were genetically related to globally circulating human G1, G3, G9, and G12 strains. Of note is that the NSP4 gene of strain A23 exhibited the closest relationship with the cognate genes of human-like bovine strains as well as human strains, suggesting the occurrence of reassortment between human and bovine strains. Furthermore, strains A14, A25, P02, P39, and P43 were very closely related to one another in all the 11 gene segments, indicating derivation of the five strains from a common origin. On the other hand, strain A23 consistently formed distinct clusters as to all the 11 gene segments, indicating a distinct origin of strain A23 from that of strains A14, A25, P02, P39, and P43. To our knowledge, this is the first report on whole genome-based characterization of G12 strains that have emerged in Myanmar. Our observations will provide important insights into the evolutionary dynamics of spreading G12 rotaviruses in Asia.