China Animal Husbandry and Veterinary Medicine ›› 2020, Vol. 47 ›› Issue (10): 3401-3409.doi: 10.16431/j.cnki.1671-7236.2020.10.040

• Clinical Veterinary Medicine • Previous Articles     Next Articles

Diagnosis and Pathogen Analysis of Mixed Infection of Porcine Reproductive and Respiratory Syndrome Virus,Porcine Circovirus Type 2 and Haemophilus parasuis

DENG Tongwei1,2, XUE Yanan2, LU Jianzhou1,2, XIA Yanxun1,2, CHEN Lulu1, GUO Yiwen1, PENG Liming1, JIANG Zenghai1,2, QIAO Hongxing1,2, XU Yaohui1,2, ZHANG Xiaozhan1,2   

  1. 1. College of Veterinary Medicine, Henan University of Animal Husbandry of Economy, Zhengzhou 450046, China;
    2. Henan Engineering and Technology Research Center of Veterinary Biotechnology, Zhengzhou 450046, China;
    3. Mianchi Agricultural and Rural Burea in Henan Province, Sanmenxia 472400, China
  • Received:2020-04-02 Online:2020-10-20 Published:2020-10-17

Abstract: To identify the causative agent of porcine respiratory disease complex (PRDC) occurred at a pig farm in Kaifeng city,Henan province,we identified the potential causative bacteria of the morbid nursing piglets by bacterial test and drug sensitivity test of the clinical samples (lung,liver and spleen),and detected the common potential pathogens causing PRDC diseases by PCR and RT-PCR assays,including porcine reproductive and respiratory syndrome virus (PRRSV),porcine circovirus type 2 (PCV2),swine influenza virus (SIV),pseudorabies virus (PRV),classical swine fever virus (CSFV) and Mycoplasma hyopneumoniae (Mhp),and then sequcing and phylogenetic analysis of the structural gene of positive causative pathogens were carried out.The results showed that a Haemophilus parasuis (Hps) strain were isolated and identified by the observation of bacterial morphology and satellite phenomenon,and the sequence analysis of 16S rRNA gene.The drug sensitivity test showed that the Hps strain was sensitive to ampicillin,amoxicillin-clavulanic acid,ceftiofur and tetracycline.Meanwhile,PCR and RT-PCR assays indicated that all the samples were positive for PRRSV and PCV2,and named the involved strain as PRRSV/HN-2019 and PCV2/HN11-2019,respectively.Sequencing and phylogenetic analysis of the ORF5 gene of the newly identified PRRSV revealed that the PRRSV/HN-2019 strain was closely related to the NADC30-like strains and grouped into NADC30-like genotype clade.And cap gene of the newly identified PCV2 strain the PCV2/HN11-2019 strain was closely related to the PCV-2d strains and grouped into PCV-2d genotype clade.In conclusion,this study demonstrated that the morbid piglets were co-infected with PRRSV,PCV2 and Hps,which provided a basis for the development of effective control strategies in the pig farm.

Key words: porcine respiratory disease complex (PRDC); Haemophilus parasuis (Hps); porcine reproductive and respiratory syndrome virus (PRRSV); porcine circovirus type 2 (PCV2); co-infection; etiology analysis

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