Highly pathogenic Porcine Reproductive and Respiratory Syndrome virus (HP-PRRSV) was firstly characterised in 2006 in China, according to Deping Han and co-authors in a paper in the journal, Veterinary Microbiology. The virus has caused great economic loss to the Chinese swine production in recent years.

In their experiment, the researchers experimentally infected SPF pigs using two strains of PRRSV with different pathogenicity and observed the lung pathological changes looking for new sights on the possible pathogenesis associated with the virulence of HP-PRRSV.

The HP-PRRSV-infected pigs died and exhibited severe pathological changes of lungs featuring increased neutrophils, mast cells and mononuclear macrophages, compared with the pigs inoculated with low pathogenic (LP-) PRRSV.

Furthermore, the pigs infected with HP-PRRSV showed the higher levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, interleukin (IL)-8 and histamine, leukotriene B4 (LTB4), platelet activation factor (PAF) in sera than those inoculated with LP-PRRSV.

Fibrosis of the lung was also observed in the HP-PRRSV-infected pigs.

The researchers report that the aberrant immune responses triggered by HP-PRRSV infection are closely related to acute lung injury (ALI), and especially the pathological changes in lung vascular system are of particular significance. These associated pathological changes of lung are in part responsible for the additional morbidity and mortality observed in HP-PRRSV infection, added Han and co-authors.

Reference

Han D., Y. Hu, L. Li, H. Tian, Z. Chen, L. Wang, H. Ma, H. Yang and K. Teng. 2014. Highly pathogenic porcine reproductive and respiratory syndrome virus infection results in acute lung injury of the infected pigs. Veterinary Microbiology. 169(3-4):135–146.

March 2014