Current View on Genetic Relationships within the Bunyamwera Serological Group

The Bunyamwera serological group includes a number of geographically widespread viruses that are related but not identical and have serological cross-reactivity. As the first group members were obtained in the pre-sequencing era, their classifications (group attribution, species differentiation) were originally based on serological reactions. At the same time, the accuracy of the typing in each case depended on the variety of viruses that the researcher had as a comparison panel. With the advent of sequencing techniques, it has become customary to use identity thresholds (nucleotide or amino acid composition) as demarcation criteria for the interspecific differentiation of viral species. Identity thresholds are determined by the International Committee on Taxonomy of Viruses (ICTV) and are regularly reviewed. Similar criteria were established for the Orthobunyavirus genus, which includes members of the Bunyamwera serological group. On the basis of these criteria, the species attributions of some members of the serological group need to be clarified. For this purpose, we analyzed sequences (available in NCBI GenBank) of viruses belonging to the Bunyamwera serological group in order to clarify their phylogenetic positions on the basis of the current demarcation criteria established by the ICTV.