Four arthropod-borne viruses - Bunyamwera and Wyeomyia, both in the litterature for many years, and Cache Valley and Kairi viruses, newly discovered - have been found to be related serologically among themselves and not to viruses in arbor virus groups A, B and C. This finding fulfills the criteria for the establishment of a new antigenic group in the arbor viruses. In the past, such groups have been designated alphabetically; however, as already indicated, this type of nomenclature may, with increasing number of groups, cease to be practical, and furthermore, may result in conflicting designations by independent investigators. For these reasons, it is considered advisable, at least pending final solution of the problem of nomenclature of arthropod-borne virus groups, to designate this new group by the name of one of its members. Accordingly, the designation Bunyamwera Group has been selected.
ADDENDUM
Since the data on which this paper is based were obtained, we have received for study other virus isolates from Africa, India and South America which belong to this new group but appear to have sufficient individuality to justify consideration as specific entities. One of these, isolated and described bv Kokernot et al. in South Africa, has been designated Germiston virus. In addition, we have evidence that there may be differences among the several strains of Wyeomyia virus under study which eventually may justify further subgrouping. It is anticipated that the Bunyamwera Group will expand rapidly.