Antimycobacterial antibodies in Dasypus novemcinctus infected with Mycobacterium leprae and their correlation with the serum levels of lactate dehydrogenase

Discovery of armadillos (Dasypus novemcinctus) as animals susceptible to infection with Mycobacterium leprae, has allowed the experimental study of leprosy to extend beyond the limits of the mouse footpad. Armadillos, however, do not all become equally infected with a given dose of M. leprae. Therefore, it would be advantageous to establish a technique for the early identification of those animals bearing the disease. Infection in armadillos originates systemic involvements which includes liver damage and the consequent release of LDH into circulation before the appearance of the clinical signs of the disease. In this study, where an enzyme-linked immunoassay for the detection of antimycobacterial antibodies was developed, those very same animals that showed an increase in their serum LDH activity showed the presence of anti-M. leprae antibodies to significant titres and eventually the presence of disease. From the results with some animals, it appears that the presence of antimycobacterial antibodies occurs before the elevation in the serum LDH activity. Periodical measurement of both antimycobacterial antibodies and LDH activity in the sera of M. leprae-inoculated armadillos may help one to detect the early infection, decide whether or not an animal is indeed infected, and decide how to proceed with the animals under investigation. The results also reveal some of the immunological and biochemical consequences of the M. leprae-infection in the armadillo.