Experimental immunosuppression and infection of chickens with Quaranfil virus.

In ovo hormonal bursectomy of chick embryos was carried out by chorioallantoic membrane inoculation with testosterone propionate at the 18th day of embryonation. At hatching immunosuppression was complemented with sublethal X-irradiation. At 40 days of age the immunomanipulated and control chickens were inoculated subcutaneously with a single dose of Quaranfil virus. It was observed that bursectomy and bursectomy with sublethal X-irradiation prolonged viraemia up to the 20th day following virus infection with a significant reduction of natural haemagglutinins and of virus induced specific antibody response.