鸡传染性法氏囊病病毒X-28弱毒株的致病性试验

在Vero细胞上适应且连续传17代的传染性法氏囊病病毒X毒株IBDVX,再经鸡胚成纤维细胞CEF连续传代后,得到了适应CEF细胞生长且毒力相对稳定的的弱毒株(IBDVX-28)。IBDVX-28~IBDVX-43代毒均能在72h~96h内产生明显的细胞病变效应(CPE),半数细胞感染量(TCID50)在10-8.47/0.1mL~10-9.26/0.1mL之间,半数鸡胚感染量(EID50)在10-4.71/0.2mL~10-5.80/0.2mL之间。致病性试验表明,各代次毒能引起10日龄鸡胚40%~50%的感染或死亡,对30日龄SPF小鸡基本无致病性,所有试验鸡均未见法氏囊明显的眼观病变,囊指数(b/B)平均为0.35±0.040;IBDVX-28代毒在雏鸡体内回归6代,均未见法氏囊明显的眼观病变,囊指数保持稳定。

Attenuation of Infectious bursal disease virus X-28 Strain and its Pathogenicity

IBDV X-28 strain was attenuated virus strain, which was adapted in chicken's embryo fibroblasts (CEF) and had stabile pathogenicity. It was adapted through 17 times in Vero and 27 times in CEF. Cytopathic effect (CPE) of IBDV X-28IBDV X-43 were observed from 72 hour to 96 hours. TCID_(50)/0.1mL was between 10~(-8.47) and 10~(-9.26 )and EID_(50)/0.2mL was between 10~(-4.71) and 10~(-5.80). The results of pathogenicity tests showed that the virus of each generation could lead the embryo infection or death and the ratio of infection or mortality was from 40% to 50%. It has no obvious pathogenicity to 4-week-old SPF chickens and bursa were all no the visual pathologic change. Bursa and body ratio(b/B) was 0.350.040 in average. IBDV X-28 could not return to a virulent strain because it propagated 6 generation in SPF chickens,but did no harm to bursa and caused bursa-body ratio changes.