鸭源鸡杆菌对SPF雏鸡的感染特性研究

Infection and transmission characteristic of Gallibacterium anatis in experimentally infected SPF chicks

为研究鸭源鸡杆菌的流行病学特性,本研究采用从自然病例分离得到的鸭源鸡杆菌人工感染4日龄SPF雏鸡,通过形态学、PCR、荧光定量PCR和组织学等方法分别对感染后SPF雏鸡的组织脏器进行了细菌分离、检测和鉴定,用ELISA对其血清抗体水平进行检测。结果表明,人工感染鸡无临床症状,组织学检查感染鸡的肝脏、气管和肺脏组织均有损伤。人工感染后第3 d和同居感染第2 d鸡体内可分离出鸭源鸡杆菌,人工感染后第96 d仍能够分离到鸡杆菌。ELISA方法证实人工感染后47 d和同居后32 d出现抗体高峰,持续2～3周,人工感染组和同居组抗体水平均高于对照组(p<0.05);荧光定量PCR检测病料结果显示人工感染组和同居组的气管组织中细菌含量最高。本研究表明雏鸡在4日龄即可感染鸭源鸡杆菌,并能通过同居传播,长期带菌、排菌;感染后抗体产生缓慢、持续期短。本研究为鸭源鸡杆菌的流行病学、致病机理研究及防治措施的制定等提供了参考依据。

To investigate the epidemiological characteristics of Gallibacterium anatis, four day-old SPF chicks were infected with the G. anat/s isolated from naatral cases. Bacteria in organs of the SPF chicks were detected and identified post infection by the morphology, PCR, fluorescence quantitative PCR and histology, respectively, and serum antibody tiers were detected by ELISA. The results showed that no clinical signs were observed in experimentally infected birds, however, histopathologic examinations of liver, lung and trachea revealed lesions in all infected chickens. G. anaits was isolated and identified from SPF chicks 3 days post infection （p.i.） and 2 days post cohabiting infection, and it still was able to detect at 96 days p.i. ELISA detection results showed that the peak titers of antibodies in infected birds and cohabiting birds appeared at 47 and 32 days, respectively, which lasted for 2 to 3 weeks. Results of G. anaits detection in organs by fluorescence quantitative PCR showed that bacteria in tracheal from infected birds and cohabiting birds were the highest. This study showed that chicks could be infected withG. anatis as early as 4 day-old and the bacteria spread via slowly and the duration of peak was short after infection. research and prevention of G. anatis. cohabiting, long-term carrying and shedding. Antibody was produced This study provided a reference basis on epidemiology, pathogenesis.