• 33 minutes
• Podcast in Episodes
• Prof. Greg Stevenson

“Peak titres can show 1,000 times more virus in blood serum with higher virulence strains”

• 20 m
• Expertise article
• Joan K Lunney, Ying Fang, Andrea Ladinig, Nanhua Chen, Yanhua Li, Bob Rowland, Gourapura J Renukaradhya

This review addresses important issues of porcine reproductive and respiratory syndrome virus (PRRSV) infection, immunity, pathogenesis, and control.

• 3 minutes
• Expertise article

Three-week-old cesarean-derived colostrum-deprived (CD/CD) pigs were inoculated with porcine circovirus type 2 (PCV2, n 19), porcine reproductive and respiratory syndrome virus (PRRSV, n 13), concurrent PCV2 and PRRSV (PCV2/PRRSV, n 17), or a sham inoculum (n 12) to compare the independent and combined effects of these agents. Necropsies were performed at 7, 10, 14, 21, 35, and 49 days postinoculation (dpi) or when pigs became moribund. By 10 dpi, PCV2/PRRSV-inoculated pigs had severe dyspnea, lethargy, and occasional icterus; after 10 dpi, mortality in this group was 10/11 (91%), and all PCV2/ PRRSV-inoculated pigs were dead by 20 dpi. PCV2-inoculated pigs developed lethargy and sporadic icterus, and 8/19 (42%) developed exudative epidermitis; mortality was 5/19 (26%). PRRSV-inoculated pigs developed dyspnea and mild lethargy that resolved by 28 dpi. Microscopic lesions consistent with postweaning multisystemic wasting syndrome (PMWS) were present in both PCV2- and PCV2/PRRSV-inoculated pigs and included lymphoid depletion, necrotizing hepatitis, mild necrotizing bronchiolitis, and infiltrates of macrophages that occasionally contained basophilic intracytoplasmic inclusion bodies in lymphoid and other tissues. PCV2/ PRRSV-inoculated pigs also had severe proliferative interstitial pneumonia and more consistent hepatic lesions. The most severe lesions contained the greatest number of PCV2 antigen–containing cells. PRRSV-inoculated pigs had moderate proliferative interstitial pneumonia but did not develop bronchiolar or hepatic lesions or lymphoid depletion. All groups remained seronegative to porcine parvovirus. The results indicate that 1) PCV2 coinfection increases the severity of PRRSV-induced interstitial pneumonia in CD/CD pigs and 2) PCV2 but not PRRSV induces the lymphoid depletion, granulomatous inflammation, and necrotizing hepatitis characteristic of PMWS.

• Top publications | July 2023 | Expertise article
• Carlos Neila-Ibáñez et al.

Streptococcus suis can cause meningitis, polyarthritis and acute death in piglets. However, the risk factors associated with S. suis infection remain incompletely understood.