2017-2019年我国部分规模场副鸡禽杆菌的感染状况分析

Investigation and Analysis of Infectious Coryza in Some Large Scale Farms in China from 2017 to 2019

本试验在2017-2019年间从全国17个省市地区240个规模化养殖场鸡群采集1 403份临床样本,进行了副鸡禽杆菌(Apg)的分离鉴定、PCR检测和测序分析。结果显示,3年间临床疑似鸡传染性鼻炎(IC)发病鸡样品中Apg阳性率分别为38.1%、45.7%和36.4%,场阳性率分别为45.9%、41.7%和56.1%。对119株分离菌株进行HMTp210基因测序,得到A型菌株56株,占比47.1%;B型菌株14株,占比11.8%;C型菌株49株,占比41.2%,表明IC在我国广泛流行,且A、B、C三种血清型Apg菌株同时存在。选择HMTp210基因测序分型得到的A、B型和C型菌株各10株,进一步通过血凝和血凝抑制试验对分型结果进行验证,显示HI血清型鉴定结果与HMTp210基因测序分型结果一致。本试验通过对发病鸡群不同类别、不同地区、不同日龄和不同月份的Apg检出率的调查,揭示了2017-2019年我国鸡群IC发病特点及不同血清型分布情况,为我国IC的防控提供数据支撑。同时本试验证明HMTp210基因测序分型与血清型分型有较高的一致性,可为确定Apg血清型分型提供一个简便快速经济的手段。

In this study, 1 403 clinical samples collected from 240 large-scale farms in 17 provinces and cities in China from 2017 to 2019 were subjected to Avibacterium paragallinarum(Apg) isolation and identification, PCR detection and sequence typing. Results showed that the Apg positive sample rates were 38.1%, 45.7% and 36.4%, respectively, while the positive farm rates were 45.9%, 41.7% and 56.1%, respectively, from 2017 to 2019. HMTp210 gene sequence typing of 119 isolates showed that 56(47.1%) were clustered into type A, 14(11.8%) into type B, and 49(41.2%) into type C, indicating that infectious coryza appeared widespread and types A, B and C strains coexisted in Chinese chicken. Then, 10 strains each of HMTp210 gene sequence types A, B and C were selected for serotyping by hemagglutination and hemagglutination inhibition test. The results showed that the serotyping results were consistent with the HMTp210 gene sequence typing results. Epidemiological data analysis revealed the infectious characteristics of infectious coryza and the serotype distribution of Apg in different regions, seasons, breeds and age groups of chickens in China from 2017 to 2019, providing valuable data support for the prevention and control of infectious coryza in chicken industry in China. As the HMTp210 gene sequence typing demonstrates high consistency with serological typing, it offers a simple, rapid and economic alternative for determining Apg serotypes.