Genetic heterogeneity of mumps virus in the United Kingdom: identification of two new genotypes.

A reverse transcriptase nested polymerase chain reaction (PCR) was developed to detect the small hydrophobic (SH) gene of mumps virus (MuV). Phylogenetic analysis was performed on the entire SH gene sequence (318 nucleotides) and the putative SH protein (57 amino acids). At least 4 MuV genotypes were identified in the United Kingdom between 1995 and 1998 by direct sequencing of 26 PCR amplicons from a variety of specimens. Comparison of these and GenBank sequences identified 2 new genotypes in the United Kingdom. The results suggest that, after the introduction of universal mumps vaccination in the United Kingdom in 1988, there appears to have been a switch from a predominant genotype to a heterogeneous group of strains.