鸭病毒性肝炎二价灭活疫苗 (DHAV-SH和DHAV-FS株) 的制备和评价

我国鸭甲型肝炎病毒(DHAV)的快速变异及广泛流行给养鸭业造成了较大的经济损失,为研究鸭病毒性肝炎二价灭活疫苗(DHAV-SH和DHAV-FS株)的制备和评价方法,首先对我国多个鸭场进行血清型流行病学分析,从201株DHAV-1、38株DHAV-3中筛选出6株毒力较强的DHAV,验证了DHAV-1和DHAV-3为我国流行优势株,并对6株DHAV进行ELD50和LD50测定,筛选疫苗候选株后经传代确定疫苗毒种,选取F5代鸭胚胚体研磨液作为疫苗毒种,经甲醛灭活后制成3批水包油包水(W/O/W)型乳剂二价灭活疫苗实验室制品。通过安全性试验、抗体中和试验、攻毒保护及免疫交叉保护试验发现:疫苗安全性良好,雏鸭免疫后第7天可以检测到DHAV中和抗体,第14-21天的攻毒保护率为90%-100%,免疫持续期可达5周以上,DHAV-SH和DHAV-FS之间的交叉保护为20%-30%。研究表明本试验研制的鸭病毒性肝炎二价灭活疫苗实验室制品安全且高效,为我国DHAV预防和控制提供了一种新方法和新产品。

Development and evaluation of an inactivated bivalent vaccine against duck viral hepatitis

The rapid mutation and widely spread of duck hepatitis A virus (DHAV) lead to the vast economic loss of the duck industry. To prepare and evaluate bivalent inactivated vaccine laboratory products of DHAV, 6 strains were screened from 201 DHAV-1 strains and 38 DHAV-3 strains by using serotype epidemiological analysis in most of the duck factory. Vaccine candidate strains were selected by ELD50 and LD50 tests in the 6 strains. Continuously passaged, the 5th passaged duck embryos bodies grinding fluid was selected as vaccine virus seeds. The virus seeds were treated with formaldehyde and water in oil in water (W/O/W) emulsions, making into three batches of two bivalent inactivated vaccine laboratory products. The safety test, antibody neutralization test, challenged protection and cross immune protection experiment suggested that the vaccines possessed good safety, and neutralizing antibodies were detected at 7th day and the challenged protection rate reached 90% to 100% at the 14th and 21st day. Moreover, immune duration of ducklings lasted more than five weeks. However, cross-immunity protection experiments with DHAV-SH and DHAV-FS only had 20%?30%. The two bivalent inactivated vaccine laboratory products of duck viral hepatitis were effective and reliable, providing a new method as well as a new product for DHAV prevention and control.