Procedures for identification of arthropod-borne viruses.

Owing to the existence of antigenic groups and to the consequent characteristics of the immune response of a host to grouped viruses, certain logical steps are advisable in the process of identification of an arthropod-borne (arbor) virus. The first of these steps is the determination of the arthropod-borne nature of the virus. Since no antigenic property is known to be common to all arbor viruses, the decision is based on other biological properties and on the circumstances of isolation. The second step is determination of the antigenic group. For this are used hyperimmune sera with considerable cross-reactivity within the group, as well as the test that gives the most overlap. The third step is determination of type within the group. Simple immune sera and the least cross-reactive test are used at this step.Viruses that belong in minor groups or are ungrouped often constitute a big problem owing to the fact that, once the major groups have been eliminated from further consideration, comparative studies must be conducted with practically all the remaining viruses before a definitive answer is reached.