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Concurrent highly pathogenic porcine reproductive and respiratory syndrome virus infection accelerates Haemophilus parasuis infection in conventional pigs
- Yu, Jiang, Wu, Jiaqiang, Zhang, Yuyu, Guo, Lihui, Cong, Xiaoyan, Du, Yijun, Li, Jun, Sun, Wenbo, Shi, Jianli, Peng, Jun, Yin, Feifei, Wang, Dapeng, Zhao, Pengwei, Wang, Jinbao
- Veterinary microbiology 2012 v.158 no.3-4 pp. 316-321
- Haemophilus parasuis, Porcine reproductive and respiratory syndrome virus, gene targeting, heart, histopathology, lungs, polymerase chain reaction, serotypes, swine
- This study was aimed at determining the effect of highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) on Haemophilus parasuis (HPS) in co-infection. A quantitative real-time PCR targeting infB gene, which is conserved among different HPS serotypes, was developed to improve the accuracy and speed of the detection of HPS. A total of 32 four-week-old conventional pigs were distributed randomly into four groups: pigs in group I were intranasally infected with HP-PRRSV first, and were then intraperitoneally inoculated with HPS on 5 days after HP-PRRSV infection; pigs in group II were intranasally inoculated with HP-PRRSV alone; pigs in group III were intraperitoneally inoculated with HPS alone; pigs in group IV were intraperitoneally inoculated with physiological saline. The amount of HPS in serum on 0, 3, 6, 9 and 12 days post-inoculation (dpi) with HPS were detected using the established quantitative real-time PCR. Clinical signs, pathological changes and histopathological lesions were observed. The amount of HPS in serum reached 10⁶copies/μl at 3dpi with HPS in pigs of group I, while it arrived 10⁵.⁷copies/μl at 9dpi with HPS in pigs of group III. The HPS loads in hearts and lungs were much higher than in other tissues. The study showed that HP-PRRSV was able to accelerate HPS infection and loads.