An understanding of the molecular epidemiology and the extent and origin genetic variation of rotaviruses is of basic importance to the development of an effective strategy for immunoprophylaxis of rotavirus disease. The recognition of naturally occurring mutants or reassortants with altered properties (virulence, antigenicity, host range, etc.), may lead to the identification of rotavirus strains of low virulence for infants and newborns which may be suitable for use in a live attenuated virus vaccine. Recently a simple dot hybridization assay and a rapid sequencing technique were developed for analysis of sequences within the genome of rotavirus isolated which may have relevance to immunity or virulence. In this context, the sequences in the VP7 gene of field isolates responsible for serotype specificity or those in the VP3 gene related to rotavirus virulence could be identified and related to the particular clinical and epidemiological features of the infections from which the strains were recovered.
