A clinical case of pulmonary nocardiosis in a dolphin (pacific bottlenose dolphin Tursiops aduncus)

Abstract

The article presents the results of a pathoanatomical autopsy of a calf of a Pacific bottlenose dolphin (Tursiops aduncus) and the results of histological and histochemical examination of selected organ samples. We have been diagnosed with pulmonary nocardiosis. Nocardiosis is an infectious disease caused by various aerobic soil saprophytes, gram-positive rods of the genus Nocardia. The disease can manifest itself as an acute, subacute, or chronic infection, often in a cutaneous, pulmonary, or disseminated form. Nocardia spp. They cause pyogranulomatous lesions of various organs in mammals, most often the lungs. Macroscopically, nodular, abscessing, erosive, ulcerative, fungous (fungal) and diffuse forms of actinomycosis are distinguished. Cattle are susceptible to actinomycosis and nocardiosis, less often pigs, sheep, goats and horses, and marine mammals. Infection occurs when dust containing bacteria is inhaled, or when bacteria enter the body directly through cuts or scratches, when contaminated soil or water enters them. Studies of seawater and the seabed have revealed the presence of actinobacteria of different genera and species. In both pinnipeds and cetaceans, young animals are more likely to become ill than adults. During histological examination with hematoxylin and eosin, as well as by the method of acid-resistant staining, it is impossible to reliably identify bacteria of the Actinobacteria class. However, modified acid-resistant staining and the Grokott method using silver methenamine not only reveals the characteristic features of actinobacteria, but also makes it possible to differentiate Nocardia from Actinomycetes. There is only one report in the literature about pulmonary nocardiosis in the Pacific bottlenose dolphin (Tursiops aduncus), and therefore we believe that our clinical case deserves attention.