Molecular characterization of group A rotaviruses circulating in Senegal over a 7-year period (2005-2011)

Group A rotaviruses are characterized by large genomic diversity that is typically studied by genotyping of the VP7 glycoprotein, which defines G-type, and the protease-sensitive VP4, which defines P-type. The aim of this study was to examine the genotypes of group A rotavirus strains circulating in Senegal over a 7-year period between 2005 and 2011. ELISA positive stool specimens were analyzed by PAGE and were genotyped by multiplex hemi-nested RT-PCR. Data were analyzed with Epi Info 7 software. Rotavirus was found in 222 samples of stools of which 32 (14.41 %) were positive on PAGE. Five electropherotype patterns were identified, three long (L1, L2 or L3) and two short (S1 or S2). Twenty-three (23) samples had a long electropherotype and nine had a short electropherotype. One hundred strains (45.04%) were analyzed by VP7 genotyping, which identified five different genotypes: G1, G2, G3, G8 and G9. Ninety-three (93) samples (41.89%) were analyzed by VP4 genotyping which showed four different genotypes: P[4], P[6], P[8] and P[11] and mixed genotypes (1.8%). Seventy seven (34.68%) samples were genotyped for both VP7 and VP4. The G1P[8] strain was the most predominant strain followed by the G9P[8] strain. Rotavirus strains circulating in Senegal are genetically diverse. Genotypes G1P[8] and G9P[8] are the predominant strains. We also found mixed infections that could favor the emergence of new viral strains. Thus, regular monitoring of genotypes circulating in the country is required.