Pulmonary silicosis in three North American river otters (Lutra canadensis)

Three adult female North American river otters (Lutra canadensis) demonstrated severe anesthetic complications shortly after being immobilized for dental procedures. Two of the animals died shortly after anesthesia, and the third otter died 2 mo after immobilization. All three animals were diagnosed with pulmonary silicosis on the basis of histopathology, polarized light microscopy, and mass spectrometry. One animal also had primary pulmonary bronchoalveolar carcinoma. Significant concurrent disease was not found in other organs. Analysis of the lung tissue by laser microbe mass spectrometry confirmed the presence of an aluminum silicate in the lung tissue associated with insulation material used in nest box construction.