VP4 and VP7 genotyping of rotavirus samples recovered from infected children in Ireland over a 3-year period

Between September 1995 and August 1998, the incidence and diversity of the main human rotavirus genotypes (G1, G2, G3, and G4 and P[8], P[4], P[6], an d P[9]) among Irish children were determined by using established and adapt ed reverse transcriptase PCR-based genotyping methods. From a total of 193 rotavirus-positive specimens collected from nine hospitals we successfully identified the P type in 182 (94%) of the samples and the G type in 165 (85 .5%) of the samples. Only four samples could not be assigned a G or P type. Two P types existed in Ireland, P[8] (78%) and P[4] (16%), and their relat ive incidence varied over the 3 years of this study. No P[6] or P[9] types were detected. G1 was the most predominant G type (55%), and the incidences of G2, G3, and G4 isolates were 15.5, 1, and 11%, respectively. Three perc ent of the samples tested had a mixed G type. A P and G type was assigned t o 158 (81.8%) of samples. Of the typeable samples, G1 P[8] was the most pre valent (65%), whereas G2 P[4] (17%), G3 P[8] (1%), G4 P[8] (12%), and mixed types (all G1/ G4 P[8]) (4%) were detected less frequently. In the third y ear a significant genotypic shift from G1 P[8] to G2 P[4] and G4 P[8] was o bserved. During the study, we noticed that the inclusion of random primers during cDNA synthesis greatly increased the specificity of the PCR typing a ssays. No correlation was seen between the contributing hospitals and a spe cific genotype. In conclusion, time coverage of infection given by the rece ntly licensed tetravalent vaccine would be significantly high in Ireland, a lthough future monitoring of genotypic changes among Irish isolates should be encouraged.