Studies on experimental tenosynovitis in light hybrid chickens.

A group of light hybrid chicks was inoculated via the footpad at 1-day-old with an avian reovirus isolated from ruptured gastrocnemius tendons, and were housed with a similar number of uninoculated chicks (in-contacts) from the same hatch. Though all inoculated birds showed swellings of the injected leg after 7 days, lesions of tenosynovitis did not develop in the other leg or in either leg of in-contacts until they were 6- to 7-weeks-old. Lesions in leg tendons, and particularly the digital flexors, persisted in both inoculated and in-contact birds until the termination of the experiment at 33 weeks of age. Reovirus was recovered for varying periods from the trachea, intestine, hock and footpad of inoculated chickens commencing 1 week after infection, and from the same tissues of in-contacts but from 2 weeks, and generally for shorter periods. In both groups virus persisted for at least 13 weeks in the hock joint or surrounding tissues and cloacal swabs were positive between the 14th and 16th weeks after inoculation. Fluorescent antibody staining demonstrated penetration of the virus into the tendons. Precipitating antibodies to the reovirus were detectable in both groups between the 3rd and 24th weeks after infection.