Physicochemical and morphological relationships of some arthropod-borne viruses to bluetongue virus--a new taxonomic group. Physiocochemical and serological studies.

Several arthropod-borne viruses were grouped on the basis of relative stability to lipid solvents and sodium deoxycholate, lability at pH 3"o, and lack of antigenic relationship to major arbovirus serologic groups A, B, and Bunyamwera. These viruses, previously ungrouped or in minor serogroups, include bluetongue, epizootic haemorrhagic disease of deer, Eubenangee, IbAr 22619, B 1327, Colorado tick fever, African horse sickness, Irituia, Changuinola, BeAr 35646, BeAr 4IO67, Kemerovo, Chenuda, Tribec, Wad Medani, Mono Lake, Huacho, Lebombo, Palyam, D'Aguilar, G8886, G~5534, Corriparta, Acado, MP359, CH9935, and MRM 1o434. In contrast to other arboviruses, the reduction in infectivity of these viruses caused by lipid solvents or sodium deoxycholate was less than }o 1'5 suckling mouse intracerebral LD50. This degree of sensitivity was reproducible and was significantly different from the absolute resistance of reoviruses and picornaviruses. After exposure of each of these viruses to pH 3"o for 3 hr, no residual infectivity was recovered. By complement-fixation testing no serological relationship to members of other virus taxonomic groups was found. The viruses themselves had no common group antigen but were placed into ten serologically distinct subgroups on the basis of individual cross-reactions. Although probably containing a doublestranded RNA genome, the relatively solvent resistant arboviruses were distinguished from reoviruses by acid lability, slight solvent sensitivity, and serology.