羊口疮活毒免疫接种的研究

本文利用羊口疮活毒就羊口疮的免疫特性和免疫方法进行了一系列研究.羊只接种活毒后15日即可产生明显的免疫力,按种后30日开始出现完全的免疫力,免疫持续期长达8个月。活毒对羊只的最小免疫量即为其最小感染量。在免疫持续期内,第二次免疫接种对羊只的免疫力似无明显的加强作用。股内侧皮肤毒和口唇皮肤毒具有相同的免疫作用。1—16日龄幼羔对活毒接种亦可产生免疫力。利用活毒在疫区对10,000余只羊作大规模预防接种收到良好效果。在发病群用活毒进行紧急接种,在隔离的条件下能制止疫情传播。

Studies on Immunization of Orf Using Live Virus

In order to clarify some problems encountered in immunizing she- ep and goats against Orf (Contagious ecthyma)by the conventional method introduced by Glover,a series of experiments were initiated. The results obtained were as follows.The specific immunity engende- red by the live vaccine infection seemed to appear 7 days after va- ccination,it was well advanced after 15 days and of substantial deg- ree after 30 days.The duration of immunity appeared to be as long as 8 months.There was no improvement on both the degree and duration of the existing immunity after revaccination.The minimum immuni- zing dose varied with the infective titers of viruses derived from sca- bs of affected animals,in other words,the minimum immunizing dole is just the minimum infective dose.As to the protective effi- cacy,there were no significant differences between the lip scab and the inside thigh scab.Suckling kids aged from 1—16 days were su- ccessfully vaccinated and found immune to subsequent challenge.An extensive field trial was carried out on a ranch where the disease had long established.No reinfection was observed among the vacci- nated animals.The emergency immunization under isolation conditi- ons could control the spread of Orf in flocks where the disease al- ready broke out.The authors concluded that the immunization with live Orf virus can be recommended for use only on premises where the disease is prevalent,