Pathologic and ultrastructural findings in sheep in Morocco with naturally occuring jaagsiekte (sheep pulmonary adenomatosis)

Abstract

Jaagsiekte was studied in the lungs of 85 sheep of Sardi and mixed breeds ranging from 7 months to 8 years of age. Lungs were examined grossly, histologically and, in five cases, by transmission electron microscopy. Lesions in lungs with jaagsiekte were described: they consisted of multiple focal to coalescent neoplastic nodules. Microscopic architecture of the neoplasms was similar in all cases, and lesions were seen as foci of cells arranged in glandular-like patterns (acinar and/or papillary). Intraalveolar fibrosis was prominent in many cases, specially in chronic ones, and alveolar macrophages were consistently found within alveolar spaces. In some cases (38/85), nodules or masses of myxomatous-like tissue were seen in the vicinity of adenomatous areas. Associated verminous pneumonia, hydatid cysts, and secondary bacterial bronchopneumonia were frequently encountered. Ultrastructurally, the proliferating neoplastic cells appeared to result from the transformation of Type II pneumocytes. Neither metastatic lesions nor viral inclusions were observed during this investigation. Sheep in the present study were not tested for antibodies to ovine lentivirus, maedi/visna. This descriptive study provides a morphological background necessary for routine differentiation and indicates the necessity of initiating studies on viral etiology and pathogenesis of jaagsiekte in Morocco.