Pulmonary pathology in white-eared opossums (Didelphis albiventris) with natural Heterostrongylus heterostrongylus () infections.

Carcasses of road-killed wild animals provide critical insights into animal health and environmental conditions. However, data on the presence of lung parasites and their effects on the health of white-eared opossums are limited. This study examines lung parasites and their pathological effects on white-eared opossums (Didelphis albiventris) found in northern Paraná, Brazil. We collected and processed lung samples from 21 opossums using standard histological techniques. Lung nematodes were preserved and identified by their morphological traits. Heterostrongylus heterostrongylus (Travassos, 1925) was detected in nine animals (42.8%). Key histological observations included diffuse interstitial pneumonia, lymphoid tissue hyperplasia, pulmonary hemorrhage, smooth muscle hypertrophy in the pulmonary vessels, congestion, and edema. Although the immediate cause of death was hypovolemic or neurogenic shock from vehicular collisions, the findings underscore the significance of studying road-killed wild animals to evaluate wildlife health and environmental status. This research also documents the first instance of H. heterostrongylus lung infections in D. albiventris, suggesting that these parasites significantly impact lung health.