Figure 2

Histological lesions found in the PCV2-challenged pigs. Severely thicker alveolus walls were examined in the lung of pigs in the challenge-control group (A). Severe infiltration with epithelium-like macrophages (↑) was examined in the lymph nodes of pigs in the challenge-control group (C). There were no clear histological lesions in the lungs (B) or lymph nodes (D) in four out of the five vaccinated pigs.