Detection of group B rotavirus in an adult with acute gastroenteritis in Yangon, Myanmar.

In Yangon, Myanmar, a human group B rotavirus was first detected in 2007 in a stool specimen from a sporadic case of acute gastroenteritis in an adult. The strain was designated as MMR-B1. The full-length sequences of the MMR-B1 genes encoding VP7, VP4 (VP5* and VP8*), VP6, and NSP4 were determined for genetic characterization. These four MMR-B1 genes showed considerable higher sequence identities (97.2-98.4%) to those of group B rotaviruses detected in India (CAL-1 in 1998) and Bangladesh (Bang373 and Bang544 in 2000 and 2001, respectively) than to those of Chinese strains (90.7-93.6%) (ADRV and WH-1 in 1982 and 2002, respectively). Phylogenetically, the four genes of MMR-B1 were clustered into the Indian-Bangladeshi lineage. Although the deduced amino acid sequences of MMR-B1 were similar to those of strains CAL-1 and Bang373, several amino acids in VP8* were found to be different from those of the group B rotaviruses described previously. The first detection in Myanmar of a human group B rotavirus suggested endemic distribution or expansion of the group B rotavirus of the Indian-Bangladeshi lineage in Southeast Asia.