Brain Lesions in Pigs Affected with Postweaning Multisystemic Wasting Syndrome

Abstract

Abstract. Anti-porcine circovirus type 2 (anti-PCV2) immunostaining was associated with cerebellar lymphohistiocytic vasculitis combined with hemorrhages (50 pigs) or with lymphohistiocytic meningitis (23 pigs) in pigs naturally affected with postweaning multisystemic wasting syndrome (PMWS). The animals originated from 12 farms in Rio Grande do Sul, Brazil. In total, 456 unthrifty 3-to 5-month-old postweaning pigs confirmed as PMWS cases were necropsied. Although most findings mimicked those extensively reported in PMWS-affected pigs, there were distinctive brain lesions that included multiple hemorrhages in the cerebellar leptomeninges associated with lymphohistiocytic vasculitis and fibrinoid degeneration in vessels of the cerebellum and periventricular areas (69 pigs). These vascular lesions were also seen in conjunction with lymphohistiocytic meningitis (38 additional pigs). PCV2 antigen was immunohistochemically demonstrated in the cytoplasm and nuclei from intralesional perivascular macrophages and endothelial-like cells in brain tissues. Together these findings suggest that these lesions were caused by PCV2.

PMWS-like Lesions in Preweaned Crossbred Piglets Naturally Infected with Porcine Circovirus 2 in India

“…In the present study, a 30 day-old piglet with splay legs revealed PCV2 antigen labeling in the endothelial cells of capillaries and degenerating neurons. These findings agree with reported observations of brain lesions and PCV2 antigen distribution in PMWS affected pigs in Brazil (Correa et al, 2007). Since some conflicting observations on the direct association of PCV2 with congenital tremors and ataxia in piglets have been reported (Kennedy et al, 2003;Stevenson et al, 2001), this aspect needs more in-depth investigation.…”

Association of Porcine Circovirus Type 2 With Vascular Lesions in Porcine Pneumonia

“…4 However, no statistical analysis was performed in that study. The data from the current study support the hypothesis that blood vessels play a role in the pathogenesis of PCV2 infection of swine.…”

“…2,4,13,17,22,23 A marked increase in the incidence and severity of PCVAD was observed in eastern Canada in 2004 and was attributed to the emergence of the PCV2b virus cluster.…”

“…18 Involvement of the vasculature in PCV2 infection has been reported. 2,4,13,17,22,23 In vitro endothelial activation and diminished coagulation time in swine naturally infected with PCV2 were demonstrated. These changes and the presence of PCV2 antigen in endothelial cells of naturally infected pigs pointed to PCV2 infection as the cause of vascular lesions.…”

Vascular lesions and pneumonia in a pig fetus infected by porcine circovirus type 2

“…In this study, microscopic lesions were found only in the lungs, where multinucleated giant cells and prominent vascular lesions were detected first, with the parallel presence of nonsuppurative pneumonia. The presence of multinucleated giant cells in pig fetuses has so far been described only in the lymphoid organs (Opriessnig and Langohr, 2012) and vascular lesions have been reported only in growing and adult pigs with PMWS or PRDC (Opriessnig et al, 2006;Correa et al, 2007;Seeliger et al, 2007;Langohr et al, 2010;Szeredi et al, 2012;Resendes and Segalés, 2014). The presence of large amounts of PCV2 antigen in and around the blood vessels of different fetal organs suggests that the vascular system may be important in the pathogenesis of fetal PCV2 infection as well.…”