Prevalence and diversity of rotavirus strains in children with acute diarrhea from rural communities in the Limpopo Province, South Africa, from 1998 to 2000.

BACKGROUND: Data regarding the prevalence and molecular epidemiology of rotavirus infection in rural areas of Africa are limited. In this study the prevalence and genetic diversity of rotaviruses in a rural South African setting were investigated. METHODS: During June 1998 to June 2000, 420 stool specimens were collected from children with acute diarrhea who visited primary health care clinics in the rural Vhembe region, Limpopo Province, South Africa. Group A rotaviruses were detected by enzyme-linked immunosorbent assay, and the G and P types were determined by reverse-transcription polymerase chain reaction. RESULTS: Of the 420 specimens, 111 (26.4%) were positive for group A rotavirus; P[6]G1 strains predominated (32.4%), followed by P[8]G1 (13.5%), P[6]G9 (4.5%), P[4]G8 (3.6%), P[4]G1 (3.6%), P[6]G8 (3.6%), and P[6]G2 (2.7%). Dual infections, with >1 P type, were seen in 33 (37.1%) of the positive specimens. CONCLUSION: The unusual serotype and genotype combinations of rotavirus circulating in the rural communities of the Limpopo Province highlight the need for more studies to monitor the geographic distribution of rotavirus strains in rural African settings.

Rotavirus genetic diversity, disease association, and temporal change in hospitalized rural Kenyan children.

BACKGROUND: The effectiveness of rotavirus vaccines will be dependent on the immunity conferred against prevalent and emergent variants causing severe diarrheal disease. Longitudinal surveillance of disease-causing strains is a prerequisite to intervention. METHODS: Molecular characterization was conducted on rotavirus-positive stool samples from children admitted with diarrhea to a rural district hospital during 2002-2004. Extracted viral RNA was separated by polyacrylamide gel electrophoresis, and rotavirus VP4 (P types) and VP7 (G types) specificities were determined. RESULTS: Among 558 investigated cases, the predominant genotype was P[8]G1 (42%), followed by P[8]G9 (15%), P[4]G8 (7%), P[6]G8 (6%), and P[8]G8 (4%), with 10% mixed strains. Overall, there were 6 different P types and 7 G types. No association was identified between genotype and child age, sex, or severity of diarrhea. The P and G genotypes and polyacrylamide gel electropherotypes showed significant temporal variation in frequency: P[8]G1 decreased from 51% (95% confidence interval [CI], 43%-58%) in 2002 to 30% (95% CI, 24%-37%) in 2004, and P[4]G8 increased from 2% (95% CI, 0%-5%) in 2002 to 13% (95% CI, 9%-19%). Quarterly data revealed seasonally endemic and emergence and/or decay patterns. CONCLUSIONS: Our study of rotavirus strains causing severe diarrhea in rural Kenyan children showed a predominance of P[8]G1 and confirms the importance of G8 and G9 strains in sub-Saharan Africa. Considerable genetic diversity of rotavirus strains was observed, including substantial mixed and unusual types, coupled with significant temporal strain variation and emergence. These results warn of variable vaccine efficacy and the need for long-term surveillance of circulating rotavirus genotypes.