Microscopic evaluation of tissue lesions following infection of 8-week-old piglets with the highly virulent porcine reproductive and respiratory syndrome virus 1 (PRRSV-1) Lleida 029_22 strain

(A) Representative images of histopathological examination of lungs, lymph nodes, tonsil, and spleen from negative control and infected pigs, stained with hematoxylin and eosin (10× magnification). (B) Representative images of lung, lymph node, tonsil, and spleen sections from negative control and infected animals, stained with a PRRSV N protein antibody by immunohistochemistry (IHC) (40× magnification). Arrows indicate positive signals.