Introduction: Pathomorphological changes in the lungs, stomach, and small intestines of wild boars infected with Metastrongylus spp., Ascarops strongylina, and Macracanthorhynchus hirudinaceus were investigated. Material and Methods: Dissection of 11 wild boars was performed, and parasitised organs were histologically investigated by common techniques. Results: Macroscopic lesions in the lungs infected with Metastrongyus spp. were seen within the apical parts of the large lobes, irregular in form, pale greyish in colour, and compact in consistency. The main pathohistological findings were: the presence of parasite forms, and lymphocytes and neutrophils in the lumen of bronchi and bronchioles, desquamation of the bronchial and bronchiolar epithelium, emphysema, thickening of alveolar septa, hyperaemia, alveolitis, infiltration of the interstitial tissue with giant cell, monocytes and eosinophils, and peribronchial and disseminated lymphoid hyperplasia. The principal observations accompanying infection with A. strongylina were inflammation and focal mucosal damage in the stomach, the latter clearly demarcated from the surrounding tissues. Severe injuries in the place of attachment of M. hirudinaceus to the wall of the small intestine were seen. Intestinal villi, underlying mucosa, and submucosa were destroyed, and an intense inflammatory reaction was present. Conclusion: The histopathological lesions showed wide diversity, varying from mild to severe; but none of them were lethal.
