Characterization of human group C rotavirus in Argentina

Abstract

A survey was conducted for identification of human group C rotaviruses in stool specimens taken from children suffering diarrhea in suburban Buenos Aires regions. Among 90 true negative group A samples as defined by ELISA, RT-PCR and PAGE, five were positive by group C specific RT-PCR (VP7 and VP6 genes) and three of these samples exhibited the characteristic 4-3-2-2 dsRNA pattern of group C rotavirus. These results were further confirmed by electron microscopy and by ELISA for detection of group C VP6 specific antigens. Sequence analysis of the VP7 gene from one of these isolates revealed a 97.3-98.6% nucleotide identity and up to 99.1% protein homology with human group C rotavirus strains found scattered throughout the last ten years in other countries. Conversely, similar analysis performed with porcine strains showed a much lower homology degree both at the nucleotide (75.5% nucleotide identity) and amino acid level (85.5% protein homology). Detection of group C rotavirus in children with acute diarrhea in Argentina extends the identification range of this agent in the region and is consistent with previous reported data that demonstrate a global distribution of this virus.

Incidence of Group C Human Rotavirus in Central Australia and Sequence Variation of the VP7 and VP4 Genes

“…This indicates that the evolution or drift of these genes is slow. It is also very much in keeping with the results of other studies in which the sequences of these human group C rotavirus genes from isolates from a number of different countries were compared and a very high degree of sequence conservation was found (1,3,4,6,9). Our results, including the VP7 and VP4 gene sequence comparisons between the central Australian and overseas isolates, therefore confirm and extend the findings presented in the other studies.…”

“…Our results, including the VP7 and VP4 gene sequence comparisons between the central Australian and overseas isolates, therefore confirm and extend the findings presented in the other studies. These results also support the contention that human group C rotaviruses evolved relatively recently and possibly belong to a single globally distributed genotype (3,6,9).…”

“…Changes in the sequences of both the VP7 and VP4 genes were evident over the 7-year period but they were few, particularly relative to the differences in sequence between the equivalent human and animal group C rotavirus genes (1,3,4,6,9). This indicates that the evolution or drift of these genes is slow.…”

“…Group A rotaviruses are the most common cause of severe diarrhea in infants and young children, but they also infect adults (10). Group C rotavirus infection in humans occurs both in children and adults, usually in sporadic cases or clustered outbreaks, and has now also been identified worldwide (1,3,8,9,11,12,(14)(15)(16)(17)20). However, compared to group A rotaviruses, the identification of group C rotaviruses has been far less common, and neither the overall disease burden nor the epidemiology of this group of rotaviruses is yet entirely clear (9).…”

“…Sequence variation is also evident between VP7 genes of human and animal group C rotaviruses, but among human group C rotavirus isolates themselves from many different parts of the world remarkable sequence conservation has been noted in this gene (1,3,6,9,11). A high degree of conservation has also been evident between the sequences of the VP4 genes of human group C rotavirus isolates from different parts of the world, but a greater difference was noted between these sequences and those of the VP4 genes of bovine and porcine group C rotavirus strains (1,4).…”