Genetic characterization of G12P[6] and G12P[8] rotavirus strains collected in six African countries between 2010 and 2014
Abstract Background: G12 rotaviruses were first observed in sub-Saharan Africa in 2004 and since then have continued to emerge and spread across the continent and are reported as a significant human rotavirus genotype in several African countries, both prior to and after rotavirus vaccine introduction. This study investigated the genetic variability of 15 G12 rotavirus strains associated with either P[6] or P[8] identified between 2010 and 2014 from Ethiopia, Kenya, Rwanda, Tanzania, Togo and Zambia. Methods: The investigation was carried out by comparing partial VP7 and partial VP4 sequences of the African G12P[6] and G12P[8] strains with the available GenBank sequences and exploring the recognized neutralization epitopes of these strains. Results: The findings suggested that the VP7 and VP4 genes of the G12 strains circulating in African countries are closely related at the nucleotide and amino acid level, irrespective of country of origin and year of detection, although there was a unique clustering of the Ethiopian strains. Neutralization epitope screening revealed that rotavirus VP4 P[8] genes associated with G12 had amino acids similar to those reported globally including the vaccines RotaTeq and Rotarix. Conclusions: At present it appears to be unlikely that widespread vaccine use has driven the molecular evolution and sustainability of G12 strains in Africa. Continuous monitoring of rotavirus genotypes is recommended to assess the long-term impact of rotavirus vaccination on the dynamic nature of rotavirus evolution on the continent.