Experimental Inoculation of Porcine Circovirus 3 (PCV-3) in Pregnant Gilts Causes PCV-3-Associated Lesions in Newborn Piglets that Persist until Weaning

Figure 4

(a) Mesenteric arteries from a piglet at weaning from the T1 group showing multifocal lymphohistiocytic periarteritis, with occasional and segmental involvement of the tunica media (arteritis), score 3 (H&E). (b) PCV-3 ISH labelling of the mesenteric arteries, score 3 (hematoxylin counterstain). (c) Mesenteric artery from a piglet at weaning from T2, showing focal lymphohistiocytic periarteritis and arteritis, score 1 (H&E). (d) PCV-3 ISH labelling from the same animal showing low amount of viral genome in the tunica media, score 1 (hematoxylin counterstain). (e) Mean periarteritis (PA, left columns) and ISH (right columns) scores at the mesenteric arteries in piglets from the T1 group at farrowing (with low and high viral load), and T1 and T2 groups at weaning (high viral load). (f) Heart section revealing focal loss of cardiomyocytes and replacement with loose fibrous tissue with lymphohistiocytic inflammation, score 3 (H&E). (g) PCV-3 ISH labelling of the myocardial section revealing abundant PCV-3 genome, especially in the inflamed area, score 3 (hematoxylin counterstain).