Leprosy in wild armadillos (Dasypus novemcinctus) on the Texas Gulf Coast: anatomic pathology.

Recent studies of the "naturally occurring leprosy-like disease of wild armadillos" establish that the causative bacillus is genetically identical to M. leprae from human sources, and thus the disease is a zoonosis, sylvatic leprosy. A recent survey of 451 wild armadillos from the Texas Gulf Coast demonstrated sylvatic leprosy in 4.66%. This companion study reports the anatomic pathologic changes seen in the 17 leprous and 17 nonleprous armadillos necropsied in that survey. Findings support previous studies on the histopathology and pathogenesis of sylvatic leprosy, but a broader spectrum of histologic changes are noted.

Leprosy in wild armadillos (Dasypus novemcinctus) on the Texas Gulf Coast. Ultrastructure of the liver and spleen.

Recent studies have established that the "naturally-occurring leprosy-like disease of wild armadillos" is, indeed, caused by Mycobacterium leprae indistinguishable from M. leprae from human lepromatous leprosy. The present study reports the ultrastructure of the mycobacteria and host response in deep viscera, liver and spleen, in Texas armadillos with sylvatic leprosy. Evidence for acid-fast bacillary proliferation in these organs and penetration of hepatocytes is given. Acid-fast bacilli concentrated in activated macrophages in Billroth cords and sheaths of Schweigger-Seidel of the spleen and in Kupffer cells of the liver. Both mycobacteria and host response seen in lepromata of sylvatic leprosy, lepromatous lesions produced by injection of inocula from human lepromata and human lepromata, are compared.

Leprosy in wild armadillos (Dasypus novemcinctus) of the Texas Gulf Coast: epidemiology and mycobacteriology.

A significant prevalence of leprosy has been demonstrated in wild Louisiana armadillos. The Texas Gulf Coast still has endemic human leprosy, and recent mores in Texas have markedly increased armadillo-human contact. Armadillos were screened by physical examination, and by ear-snip and slit-scrape technique. Animals that screened "positive" were sacrificed and necropsied under aseptic conditions. Liver, spleen, gross lesions, and four groups of lymph nodes were cultured for mycobacteria and were studied histologically. Base ratios and DNA homology with Mycobacterium leprae were determined on mycobacteria from two armadillos (and two tissues from one of these); these studies indicate that the organism found in Texas armadillos is M leprae. Twenty-one of the armadillos were leprous--4.66%. The local prevalence varied from 1.0% to 15.4%. Epidemiologic implications of these findings and the occurrence of other concomitant mycobacterial infections are discussed.