Utility of semithin sections in the diagnosis of donovanosis.

The relative merits of tissue smears, paraffin sections and semithin plastic embedded sections in the diagnosis of donovanosis were assessed. In three cases reported negative or doubtful for the organisms by the former two methods, semithin plastic sections provided definite diagnosis. The latter method revealed in addition the organisms in epidermis and perivascular locations. From amongst the three stains: toluidine blue, Leishman's and thionine azure II basic fuchsin, the last mentioned was found to be the method of choice for demonstrating the organisms differently from the host cells.

An ultrastructural study of donovanosis.

In an ultrastructural study undertaken on donovanosis, the inflammatory response was studied along with the fine structure of causative organisms, Calymmatobacterium granulomatis. Macrophages were seen to be activated and showed presence of numerous filopodia and increase in the number of lysosomes and rough endoplasmic reticulum. Many cells showed vacuoles of varying size in the cytoplasm some of which contained the organisms. Other cells seen included plasma cells, polymorphonuclear cells and sparse lymphocytes. In one case few multinucleated giant cells and dendritic cells with long cytoplasmic processes making cell-cell contact with other inflammatory cells were seen. Such cells have not been described in donovanosis so far. The organisms showed surface structures like pili and vesicles, the role of which is yet to be clearly understood.