Du Shuailong, Xu Fan, Lin Yidan, Wang Yawen, Zhang Yanan, Su Kai, Li Tanqing, Li Huanrong, Song Qinye
Hebei Veterinary Biotechnology Innovation Center, College of Veterinary Medicine, Hebei Agricultural University, Baoding 071000, China.
College of Animal Science and Technology, Beijing University of Agriculture, Beijing 102206, China.
Vet Sci. 2022 Sep 27;9(10):528. doi: 10.3390/vetsci9100528.
In order to diagnose a respiratory disease in a pig farm, the lungs, spleen, and lymph nodes of three dead pigs were collected for pathogen detection by PCR and isolation on the basis of preliminary clinical diagnosis. The virus isolate was identified by gene sequence analysis and Immunoperoxidase monolayer assay (IPMA). The bacterial isolate was identified by biochemical tests, 16S rDNA sequence analysis, and species- and serotype-specific PCR, and the pathogenicity was analyzed. Porcine circovirus type 2a (PCV2a) genotype from the lungs, spleen, and lymph nodes and Pasteurella (P.) multocida capsular serotypes D from the lungs were found. The PCV2a isolates could specifically bound the anti-PCV2-Cap polyclonal antibody. The 16S rDNA sequence of P. multocida isolates had 99.9% identity with that of the strain from cattle, and the isolate was highly pathogenic to mice. The results showed that the co-infection of PCV2a and P. Multocida capsular serotypes D should be responsible for the disease. The uncommon PCV2a is still prevalent in some pig farms besides the dominant PCV2d genotype. This study could provide important etiological information for effective control and treatment of the disease in pig farms.
为诊断某猪场的呼吸道疾病，在初步临床诊断的基础上，采集了3头死亡猪的肺、脾脏和淋巴结，用于通过聚合酶链反应（PCR）进行病原体检测及分离。通过基因序列分析和免疫过氧化物酶单层试验（IPMA）对病毒分离株进行鉴定。通过生化试验、16S核糖体DNA（rDNA）序列分析以及种属和血清型特异性PCR对细菌分离株进行鉴定，并分析其致病性。在肺、脾脏和淋巴结中发现了2型猪圆环病毒a型（PCV2a）基因型，在肺中发现了多杀性巴氏杆菌（P. multocida）荚膜血清型D。PCV2a分离株可特异性结合抗PCV2-衣壳多克隆抗体。多杀性巴氏杆菌分离株的16S rDNA序列与牛源菌株的序列一致性为99.9%，该分离株对小鼠具有高致病性。结果表明，PCV2a与多杀性巴氏杆菌荚膜血清型D的共同感染应为该疾病的病因。除了占主导地位的PCV2d基因型外，不常见的PCV2a在一些猪场中仍然流行。本研究可为猪场疾病的有效防控和治疗提供重要的病原学信息。
