Characterization of two decades of temporal co-circulation of four mumps virus genotypes in Denmark: identification of a new genotype

Twenty-nine Danish virus isolates and 14 serum samples from patients with m umps were genotyped by nucleotide sequencing of the small hydrophobic (SH) protein gene and the deduced 57 amino acid sequences were aligned with sequ ences of mumps virus strains published previously. Four neurovirulent genot ypes of the SH protein gene, genotypes C, D, H and a new genotype, designat ed J, were found. There was a dynamic fluctuation of the different genotype s over the two decade period of time. Genotype J was found from 1981 to 198 8; genotypes C and H exhibited a similar distribution in time. Genotype D w as found between 1979 and 1982, it then disappeared and reappeared again in 1996. From 1996 onwards, genotype D was found to be the predominant genoty pe, which is in contrast to the situation seen in the neighbouring country of Sweden, where, since 1985, only genotype A has been found.