Detection and characterization of human group C rotaviruses in Bangladesh

Abstract

Group C rotaviruses were detected by reverse transcription-PCR in 14 (2.3%) of 611 group A rotavirus-negative stool specimens from the patients admitted to the International Centre for Diarrhoeal Disease Research, Bangladesh hospital, Dhaka, Bangladesh, during July to December 2003. The low rate of detection suggested that infection with group C rotaviruses was an uncommon cause of hospitalization due to gastroenteritis. In addition, coinfections with pathogenic enteric bacteria were frequently observed in group C rotavirus-infected patients. Nucleotide sequence comparison of the VP4, VP6, and VP7 genes revealed that the Bangladeshi group C rotaviruses were most similar to Nigerian group C rotavirus strains. Phylogenetic analysis suggested that all human group C rotaviruses, including the strains isolated in our study, clustered in a monophyletic branch, which was distantly related to the branch comprised of animal group C rotaviruses.

FIG. 1.

Gel electrophoresis showing the characteristic genomic double-stranded RNA electrophoresis patterns of group A (lane A), group B (lane B), and group C (DhakaC13) (lane C) rotaviruses. The viral RNAs were analyzed by electrophoresis in a 10% polyacrylamide gel and visualized by staining with silver nitrate.

FIG. 2.

Neighbor-joining phylogenetic tree based on partial nucleotide sequences (nt 1020 to 1329) of the VP6 genes for DhakaC13 and other established group C rotavirus strains. Bo, bovine; Hu, human; Po, porcine. The numbers adjacent to the nodes represent the percentage of bootstrap support (of 1,000 replicates) for the clusters to the right of the node. Bootstrap values lower than 75% are not shown.

FIG. 3.

Neighbor-joining phylogenetic tree based on the nucleotide sequences (nt 21 to 682) of partial VP8* fragments of the VP4 genes for DhakaC13 and other established group C rotavirus strains. Bo, bovine; Hu, human; Po, porcine. The numbers adjacent to the nodes represent the percentage of bootstrap support (of 1,000 replicates) for the clusters to the right of the node. Bootstrap values lower than 75% are not shown.

FIG. 4.

Neighbor-joining phylogenetic tree based on nucleotide sequences (nt 49 to 1054) of the encoding regions of the VP7 gene for DhakaC13 and other established group C rotavirus. Bo, bovine; Hu, human; Po, porcine. The numbers adjacent to the nodes represent the percentage of bootstrap support (of 1,000 replicates) for the clusters to the right of the node. Bootstrap values lower than 75% are not shown.