Kinetic haemagglutination inhibition technique as a means of detecting antigenic variations among strains of Nigerian flaviviruses.

Seven isolates of West Nile virus and an additional isolate tentatively identified at the outset as West Nile virus, were compared by Casals' modified haemagglutination inhibition technique. Two of the isolates were nearly identical; a second set of five isolates cross-reacted among themselves within a wide range and differed from the first two; the last isolate was significantly different from the others.