某鸡场鸡传染性法氏囊病弱毒疫苗饮水免疫后发生的一次鸡病的诊断

１９９１年４月上旬，四川某鸡场对３５７０只１３日龄依莎雏鸡作法氏囊病弱毒疫苗饮水免疫，１４日龄时发病死亡９只，到２３日龄９天内共死亡８１４只，病死率达２２．８％。对２０只送检病死鸡的沙门氏菌分离率为１／２０株（５％）．但病料人工感染小白鼠试验为阴性，证明非病原菌所致，用病料与新城疫血清（抑制价１：６４０）作用后接种非免疫健康鸡１组的存活率为７５％，直接接种未与新城疫血清作用病料的２组存活率为５０％，剖检回归本动物试验自然死亡和人为处死的病鸡发现了较为典型的法氏囊病变，由此认为：法氏囊弱毒疫苗饮水免疫是引起鸡群发病死亡的主要原因。

An Accident of Disease in After Immunity of IBD in a Chicken Farm

Three thousand five hundred and seventy 13-day old chicks were immuizedized with the attenuated vaccine of IBD mixed with drinking water. Some chicks fell ill and 9 chicks died next day. The total numiber of chicks that died within 9 days after immunity was 8 14.The mortality was 22. 8%. Only one strain of Salmonella was isolated from the carcases of 20 chicks. Healthy mice which were injected with the suspension of tissues from the carcases of chicks did not present any symptom and survived after 1 2 days of the injected. It revealed that the chick illness was not due to the pathosenic bacteria. Symptoms of IBD appeared in the healthy chicks(sroup 1)injected with the susDension of tissues from carcases of diseased chicks mixed with anti-ND serum and one of them died, and only appeared in typic symptoms of IBD those(group 2)injected with the suspension of tissues and two of them died.The results of investigation and examination showed that the chicks infected with IBD,It is considered that the main cause of the disease and death of chicks is the immunity with anttenuated vaccine of IBD.