Chronic Pulmonary Lesions in the Experimental Infestation with Ascaris Suum in Domestic Pig

The aim of the study was to investigate the histopathologic lesions caused by the migration of Ascaris suum larvae through lung. Fragments of the lung were collected from a number of 10 swine (four months old), and histologically processed. Animals in this study were divided into 2 groups of 5 individuals: a group artificially infested with 1000 eggs of Ascaris suum, and another control group. Lesions present in the lungs collected from the artificially infested group varied in intensity from one area to another following the larval migration. Lungs from the control group were apparently normal. Lungs presented lesions in the bronchioli and lung interstitium. Bronchiolar epithelium showed zonal necrosis, with cellular debris in the lumen of bronchioli, whose intensity differed from one area to another of the lung parenchyma. Chronic inflammation represented by lympho-eosinophilic infiltrate (consecutive to active migration of Ascaris spp. larvae through the lung parenchyma) evolved into a chronic fibrous peri-brochiolitis that led to a local bronchiolar fibrostenosis. The chronic morphological changes lead to the transformation of the bronchiolus in a rigid tube that no longer has the ability to adapt its lumen diameter and has an altered aspect. Lesions were chronic and had an irreversible nature.