Histopathological findings in pigs of various ages suffering from spontaneous infection with the porcine reproductive and respiratory syndrome virus (PRRSV).
A retrospective study was carried out to investigate the morphology of 29 routinely necropsied German Landrace pigs of various ages, namely five fetuses, eight neonates, five suckling piglets and 11 weaners, being either serologically PRRSV-positive or born or aborted from PRRSV positive sows. Virus antigen was immunohistochemically demonstrated in 12 out of 27 (44%) lungs tested. The distinguishing histopathological features of PRRSV-induced spontaneous disease are interstitial pneumonia accompanied by secondary inflammatory alterations that become more and more pronounced with increasing age, and vascular alterations hitherto not described in animals of these age groups. The latter consist of vasculitis of the medium-sized arteries and occasionally of the veins, mainly in the lungs but also in other organs, and of perivascular lymphoplasmacytic infiltrates of various degrees of frequency and organ distribution, but present above all in the CNS-including the meninges and in the lungs. These findings, which suggest vasculotropism on the part of the PRRSV, may facilitate the histopathological diagnosis of PRRSV infections in routinely examined material.
Darbès
J
J
Institute of Veterinary Pathology, University of Munich, Germany.
Hafner
A
A
Breuer
W
W
Hänichen
T
T
Banholzer
E
E
Hermanns
W
W
D000818:Animals; D000831:Animals, Newborn; D000833:Animals, Suckling; D005315:Fetal Diseases / Q000473:pathology / Q000662:veterinary*; D019318:Porcine Reproductive and Respiratory Syndrome / Q000473:pathology*; D012189:Retrospective Studies; D013552:Swine; D014886:Weaning