Authors : Zuo Zhicai, Hongbo Dai, Lei Chen, Yuancheng Zhou, Wanzhu Guo and Zhiwen Xu
Abstract: Haemophilus parasuis mainly affect piglets during suckling period and the infected pigs showed clinical symptoms at 5-6 weeks old after weaning. To develop a specific PCR for early detection of Haemophilus parasuis, early treatment would effectively prevent phenotypic expression of the disease. A pair of specific primers were designed to amplify a 414 bp specific DNA fragment based on H. parasuis Outer Membrane Protein (OMP) gene published in GenBank also the PCR conditions were optimized. The established PCR test could detect a minimum of 425 cfu mL-1 (0.425 cfu/PCR reaction) pure cultures of H. parasuis and only H. parasuis could amplify a 414 bp specific DNA fragment. No amplification was observed while tested with the closely affiliated species and the mainly contaminating flora. From 2 days post infection (dpi) to 5 dpi, all of the piglets challenged with H. parasuis showed a fever above 41°C and all blood samples from those feverish piglets were positive for H. parasuis. Through blood PCR detection, 37 positive samples were picked out in 84 sucking pigs which were natural infected with H. parasuis, the result was verified by dissecting five positive piglets and isolating bacteria from lung tissue. The developed PCR was successfully applied for early diagnosis of H. parasuis infection, early treatment will reduce the incidence and mortality of disease.
Zuo Zhicai, Hongbo Dai, Lei Chen, Yuancheng Zhou, Wanzhu Guo and Zhiwen Xu, 2013. Development and Application of a Polymerase Chain Reaction to Early Detect Haemophilus parasuis. Journal of Animal and Veterinary Advances, 12: 140-145.