RELATIVE FREQUENCY OF HUMAN ROTAVIRUS VP4 (P)-GENOTYPES RECOVERED OVER A 10-YEAR PERIOD FROM SOUTH-AFRICAN CHILDREN WITH DIARRHEA

The relative frequency and distribution of the VP4 (P) genotypes of 22 7 human rotavirus field strains were investigated in South Africa. The stool samples were collected between 1984-1993 from infants and young children with diarrhea at Ga-Rankuwa Hospital, Pretoria, South Africa . The RNA was extracted from stools, heat denatured, and dot blotted o nto nylon membranes. The blots were hybridized to PCR-generated, P-32 radio-labelled VP4-specific probes (corresponding to the hyperdivergen t region of the VP4 gene) of the following human rotavirus VP4 genotyp es: P4, P6, P8, P9, P10, and P12. Of the 157 rotavirus strains typed b y the probes, the P8 genotype was identified most frequently in 63.7% (n = 100) of the samples. The P4 and P6 genotypes were detected less f requently in 22.3% (n = 35) and 8.3% (n = 13) of the samples, respecti vely. Five cases of dual infection between P8 and P4 genotypes occurre d, indicating the potential for reassortment between members of differ ent rotavirus genogroups. The P9 genotype could not be confirmed in 3 cases (1.9%), while the P10 genotype was not observed at all, indicati ng the scarcity or absence of these VP4 genotypes in this region. Inte restingly, we identified the newly-described P12 VP4 genotype in 6 cas es (3.8%), suggesting a wide geographical distribution. Furthermore, s everal samples with sufficient RNA by gel electrophoresis remained unt yped by the probes used in this study, and may represent putative ''ne w'' human VP4 genotype(s). (C) 1995 Wiley-Liss, Inc.