Introduction: A real-time RT-PCR method for identification and quantification of porcine epidemic diarrhoea virus (PEDV) strains in China was developed.
Material and Methods: Based on the conserved sequence of the PEDV nucleocapsid (N) gene, a primer pair and probe were designed to establish a TaqMan-MGB real-time RT-PCR assay for quantitative detection of the virus. The sequence was cloned into the pMD18-T vector and a series of diluted recombinant plasmids were used to generate a standard curve with an R2 value of 0.999.
Results: The developed quantitative PCR assay detected viral titres as low as 0.1 TCID50 with high specificity and no cross-reaction with other porcine viruses (PoRV, TGEV, PRRSV, or CSFV). The intra-batch and inter-batch coefficients of variation were both less than 1%, which indicated good reproducibility. Thirty clinical diarrhoea samples obtained from pigs in Shanghai and Fujian were analysed using this quantitative PCR assay. Out of these samples, 93.3% were found to be PEDV positive.
Conclusion: This approach is suitable for clinical sample identification and pathogenesis studies.
Five pathogen-free miniature pigs (minipigs) were infected with the virulent strain SH08 of Streptococcus suis 2 (SS2) by intramuscular injection. The pigs died consecutively within 72 h after the challenge. An additional five non-infected pigs were euthanised and used as controls. Microstructural observations showed that degeneration, bleeding, congestion, cellular necrosis, and an increase in inflammatory cells were present in all organs and tissues except the brain. Ultrastructural observations revealed mitochondrial vacuolation and malformed or missing cristae, indicating that infection of minipigs with strain SH08 of SS2 can lead to extensive lesions in major internal organs and tissues. The findings also demonstrated that the minipig is a useful model for the study of SS2 infection.