Radial immunodiffusion: a simple and rapid method for detection of Marek's disease antigen(s).

A qualitative radial immunodiffusion technique is described which detects antigen(s) in feathers from live or dead chickens infected with Marek's disease herpesvirus. Antiserum, which is incorporated into a support medium, reacts with antigen(s) in the feather tip producing a radial precipitin ring. Antigen(s) was detected in 93.3% of experimentally inoculated chickens 21 days postinoculation and in 100% of infected birds subsequently tested through 6 weeks. No antigen was detectable in the feathers of uninoculated control chickens. The technique is simple and rapid to perform. Positive tests could be detected after 1 to 2 hours of incubation. Antigen detection by the radial immunodiffusion test correlated well with other criteria of infection. This technique should have application as a laboratory research tool and as an adjunct for a rapid flock diagnosis of Marek's disease.