为确定重庆市某患病猪场的致病原并探究其生物学特性及分子进化特性，首先利用PCR方法对组织病料进行检测，结果发现副猪嗜血杆菌（Hps）和圆环病毒3型（PCV3）两种病原场为阳性。然后进行细菌分离，通过形态、培养特征和16S rDNA测序对分离菌株进行鉴定，并分析其血清型、药物敏感性、耐药基因以及生长曲线等主要生物学特性。经鉴定确定致病菌株为Hps血清5型，分离菌株对头孢他啶、苯唑西林、新霉素、卡那霉素、氯霉素、米诺环素、多黏菌素B和四环素表现为耐药，共检测到9种耐药基因；对PCV3通过分段扩增、拼接获得完整的基因组序列，通过生物学软件分析其基因结构以及基因型，经测序分析发现PCV3基因组全长2 000 bp，GC含量为50.45%，基因型为PCV3a，与广西MH823221株和美国最早报道的KT869077株具有较高的亲缘关系。本研究确定了患病猪的致病原及其主要生物学特性及分子进化特性，为临床有效防控Hps和PCV3混合感染提供了依据。
In order to identify the pathogenic agents prevalent in a farm with diseased pigs in Chongqing City and to determine their characteristics of biology and molecular evolution，the tissue samples were detected by PCR，and it was found that two kinds of pathogens including Haemophilus parasuis（Hps）and circovirus type 3（PCV3）were positive. Followed by bacteria isolation as well as identification by morphology，culture characteristics and 16S rDNA sequencing，then their serotype，drug sensitivity，drug-resistance genes，growth curve and other major biological characteristics were analyzed. It was determined that the pathogenic strain was Hps serotype 5，the isolate was resistant to ceftazidime，oxacillin，neomycin，kanamycin，chloramphenicol，minocycline，polymyxin B and tetracycline，and a total of nine drug-resistance genes were detected；PCV3 complete genome sequence was obtained by segmental amplification and splicing，then its gene structure and genotype were analyzed by the biological software. It was found that the total length of PCV3 genome was 2 000 bp，the GC content was 50.45%，and the genotype was PCV3a，which was highly close to Guangxi MH823221 strain and KT869077 strain firstly reported in the United States. In conclusion，the pathogens in the diseased pigs and its major characteristics of biology and molecular evolution were determined，which provided a basis for future effective prevention and control of mixed infection with Hps and PCV3 in practice.