Isolation of serotype hardjo and other leptospirae from armadillos in Argentina.

A serologic, bacteriologic, and histopathologic examination for leptospires was carried out on 89 armadillos (Chaetophractus villosus) from Argentina. Forty-seven per cent of the serum samples yielded positive results when tested by microscopic-agglutination. Predominant agglutination reactions were to the Hebdomadis and Bataviae serogroups. A total of 15 Leptospira isolations (from 16.8 per cent of the animals tested) were obtained from kidney tisse. Nine of the isolates were identified as belonging to the Bataviae group serotypes argentiniensis, paidjan, or bataviae; three other isolates proved to be the Canicola group serotype canicola; two others were Leptospira biflexa strains; and the last isolate was found to be serotype hardjo of the Hebdomadis group. The latter finding represents the first isolation of serotype hardjo from this animal species. Histopathologic examination of kidneys from 11 of the animals yielding pathogenic leptospires permitted a diagnosis of interstitial nephritis. This intersitial nephritis, presenting the characteristic picture of lymphoid infiltration, appeared intense in two animals, moderate in five others, and only slight in the remaining four. These histopathologic findings of chronic nephritis, combined with the high positive serologic and cultural isolation rates, suggest that the armadillo is an important natural reservoir-host for pathogenic leptospirae.