Proliferative vasculopathy and cutaneous hemorrhages in porcine neonates infected with the porcine reproductive and respiratory syndrome virus

Severe cutaneous hemorrhages with dermal and subcutaneous capillary angiopl asia were seen in aborted and stillborn piglets, concurrently with an acute outbreak of porcine reproductive and respiratory syn drome virus (PRRSV) a bortions. Histologically, the lesions consisted of angioblastic endothelial cells and immature capillary vascular structures coursing through the edem atous myxomatous dermis and subcutis. Proliferating capillaries often were surrounded by large and foamy macrophages that stained positively for PRRSV by immunohistochemistry. The sudden appearance of these vascular lesions d uring the PRRSV outbreak and their abrupt disappearance after the abortion storm, along with the immunohistochemical localization of PRRSV-positive ma crophages adjacent to the proliferating capillaries, suggest that PRRSV lik ely played a role in the development of these unusual lesions.