鸡传染性法氏囊病超强毒LX株的分离鉴定

从一免疫失败鸡场中分离到１株鸡传染性法氏囊病野毒株，命名为ＬＸ株。经血清学、鸡胚接种、病毒形态、外源病毒（ＣＡＡ、ＮＤＶ和ＩＢＶ）排除试验等证实该分离物为纯净的ＩＢＤＶ。人工感染试验表明，该ＬＸ株接种８龄ＳＰＦ鸡后第２天鸡只精神 沉郁，拉白色或绿色粪便，发病率为１００％，第３￣４天出现死亡高峰，而后很少引起死亡，死亡率达９２．３％，剖检可见全身性出血素质，法氏囊呈“紫葡萄样”外观，脾脏肿大，胸腺萎

Isolation and Identification of Very Virulent Infectious Bursal Disease Virus Strain LX

An infectious bursal disease virus(IBDV) field strain,designated strain LX,was isolated from a flock with immune failure.With the use of serological method,embryo inoculation test,electron microscopic observation ,and test for exotic viruses,the isolate was determined as a pure IBDV strain.Eight week old specific pathogen free(SPF)chickens inoculated with the strain developed severe clinical disease with a morbidity of 100%,and a death peak(up to 92.3% mortality)on the third or fourh day after inoculation.On pathological examinations,the most characteristic primary gross lesions were severe bursal haemorrhage and thymic atrophy,as well as the bone marrow with fatty change,accompanied by slight fatty liver and severe generalized hemorrhagic diathesis.Nigh day old chicken embryos were characterized by regular death with as high as 100% mortality 3 4 days after inoculation.These showed that the isolate LX was a very virulent IBDV strain.