The serologic response of duckings vaccinated with alocal isolate of duck virus hepatitis attenuated in embryonated chicken egg

j,ttenuation ot $ locally isolated ll! V straiilt (Giza-J?2) was underbakDn through 70 sorial ,passages in tooallantoic sac of 9 Qaj-old emb~onatod chieken GggaThe attenuated D V!li! strain proved to lose itapathoganicity to young QUcklings!• Giza?2 at~t ()t~ III ot the prGpa1’6d vaocine containjng lO?’!3 ELI50pe+- 0,1 ml. ~1”0 ~ooulated subcutenously to 2 Q~~olQduokJ.ings to tostit’s immunological. efi&ot, !J.1P,Q imnuneresponse was ostimatec saro~ogically including gar gel proo~pitint ind-1-rect haemagglutination and serum neut.ral.ation tosta as wo,ll as t~ughchallwith a fielvirulent strain of D~V~H~ virus No preeipitina oould be deteoted, the 1ndi1’Q4at heanagglut1nation titers ~anged between 1.s5 up to 1.10.