A method for serological differentation of closely related poxviruses.

A two-step gel precipitation reaction with antiserum to vaccinia virus, based on sequential addition of two test viruses was elaborated for differentiation of closely related orthopoxviruses. The appearance of an additional precipitation line indicated differences in the antigenic structure of the viruses compared. Differences in the antigenic structure of vaccinia, variola and monkey pox viruses as well as the antigenic identity with cow pox virus of poxviruses isolated from carnivora, elephants and okapi were established.