Geographical Distribution.—Cases of the disease have been chiefly reported from British Guiana and the West Indies. It is now recognized, however, that it occurs in India, China and Northern Australia as well as in some of the islands of the Pacific. It also occurs in Northern and Central Africa.
Grindon has reported 3 cases from the United States.
Etiology
Various spirochaetes have been reported as present in the lesions. The finding by Wise of spirochaetes resembling Treponema pallidum has not been generally accepted.
Donovan has reported the presence, in scrapings from the ulcerations, of an oval bacillus (1½ × 2 microns) which was contained in large phagocytic cells. There were sometimes several such bodies in a single cell.
Flu has recently reported the presence in plasma cells as well as occasionally in other cells of a capsulated organism which he believes related to the Friedlander group. His cultural work has not been conclusive. It is probable that this capsulated organism is merely a secondary invader.
There is also a suggestion of the cellular reaction characteristic of the chlamydozoa.
The disease is rather more common in women than in men and is rarely seen before the period of puberty. It is thought that it is transmitted by sexual intercourse.
Pathology
The pathological process manifests itself as a small round cell infiltration of the superficial portion of the corium. The growth is well supplied with blood vessels. Giant cell formation and caseation have not been noted. There is an abundance of plasma cells.