ABSTRACT
Diverse pathological conditions causing the strandings and/or deaths of several species of sea lions and seals on the northern coast of the province of Buenos Aires are being studied. Tuberculosis was diagnosed in six cases of strandings, involving two otariid seal species (one Otaria flavescens and five Arctocephalus australis), between March 1989 and December 1992. Necropsies were performed on all six cases. Granulomatous lesions were observed in the prescapular and hepatic lymph nodes. Lesions were also seen in the lungs, pleura, liver, spleen and peritoneum. Bacteriological isolation was attempted from all the samples. The isolates were identified as belonging to the Mycobacterium tuberculosis complex. Some showed characteristics consistent with M. bovis, whereas others demonstrated properties of M. tuberculosis. Genomic deoxyribonucleic acid (DNA) from these strains was analysed by restriction fragment length polymorphism (RFLP), using IS6110, a genetic marker found only in the Mycobacterium tuberculosis complex. Using the IS6110 probe, similar fingerprints were obtained, suggesting a common source of infection. However, the pattern of DNA differed from DNA patterns of M. bovis isolated from humans and cattle in Argentina, which generally contain a unique 1.9 kbp band. These results suggest that mycobacteria isolated from wild seals form a different grouping inside the M. tuberculosis complex. This is the first time that tuberculosis has been detected in wild seals from the south-western Atlantic coast.
Subject(s)
Fur Seals , Sea Lions , Tuberculosis/veterinary , Animals , Argentina/epidemiology , Atlantic Ocean , DNA, Bacterial/analysis , DNA, Bacterial/chemistry , Female , Liver/pathology , Lung/pathology , Lymph Nodes/pathology , Male , Mycobacterium tuberculosis/classification , Mycobacterium tuberculosis/genetics , Mycobacterium tuberculosis/isolation & purification , Polymorphism, Restriction Fragment Length , Tuberculosis/epidemiology , Tuberculosis/pathologyABSTRACT
Different diagnostic techniques for mycobacteria were studied in sea lions, sea elephants, fur seals, dolphins, killer whales and penguins from a sea aquarium. Three strains were isolated from fur seals. Two were classified as Mycobacterium chelonae and one as Mycobacterium fortuitum complex. There was good correlation between the results given by the intradermal tuberculin test and ELISA, but the former is recommended as a screening test on the basis of its practicality. Results and methodology of the different techniques are described.
