SUBGROUP DETERMINATION OF GROUP-A ROTAVIRUSES RECOVERED FROM PIGLETS IN NIGERIA

Subgroup analysis using subgroup-specific monoclonal ELISA revealed a preponderance of subgroup 2-specific antigens of group A porcine rotav iruses over subgroup 1. Of 113 polyacrylamide gel electrophoresis-posi tive test samples, obtained from 4 States of Nigeria, 31 (27.4%) and 4 5 (39.8%) were determined to have subgroup 1 and 2 specificities, resp ectively. However, 37 (32.7%) test samples could not be classified int o any of the known group A rotavirus subgroups. These ''unclassifiable ') samples probably had neither subgroup 1 nor 2 specificities in ELIS A or could belong to a third subgroup unknown or not investigated in t his study. In all age groups investigated, subgroup 1 and 2 specific a ntigens were prevalent. This was also observed after yearly analysis o f subgroup specificity; however, a higher prevalence of subgroup 2 spe cificity was observed in 1990 and 1991. Subgroup 1 rotaviruses were fo und in all the 4 States sampled (Plateau, Benue, Oyo, and Cross River) , whereas subgroup 2 rotaviruses were detected only in Plateau State. All rotaviruses recovered in this study had long genome electrophoreti c migration patterns, irrespective of subgroup. Thus genomic diversity of group A rotaviruses does not necessarily reflect antigenic diversi ty, as there is no mandatory correlation between genome electropheroty pe pattern and subgroup specificity.