Ocular pathology of caprine beta-mannosidosis.

Abstract

acute and chronic infections. Initially, leptospires are localized in the tubular lumen. At this stage, the organisms are numerous, intact, and well visualized by both the immunohistochemical and silver-staining methods; the perifocal inflammatory response is scanty or a b ~ e n t . ~ Inflammatory cells then surround the infected tubules; leptospires are lysed, clumped and then taken up by tubular cells. Electron microscopic studies' demonstrate the presence of degenerating leptospires within vesicles in tubular cells. This suggests that the black bodies detectable in tubular epithelia by silver staining are phagosomes containing remnants of leptospires. Our results confirm this hypothesis. In fact, these silverstained bodies react positively for leptospiral antigen. In more advanced cases, leptospiral antigen is contained in macrophages that seem to acquire it from destroyed tubular cells. The stage during which leptospiral antigen is present within the cells probably does persist for a long period of time, as suggested by Morter et a1.6 Those authors explained the continuance of an active inflammatory process in the kidneys as a result of the presence of some leptospiral antigenic components. These persisted long after the leptospires themselves were no longer detectable. In the final stage, leptospiral components are eliminated from the kidney, which at that stage has extensive fibrosis as a result of the inflammatory process.