Tropical Ulcer 



533 



tiple, as many as twenty sometimes occurring simultaneously. It 

 is thought that recovery is followed by immunity. 



Organism. — In 1885 Cunningham* described a protozoan organ- 

 ism found in the tropical ulcer, the observation being confirmed 

 by Firth, t who called the bodies Sporozoa furunculosa. Later, 

 J. H. WrightJ studied a case of tropical ulcer and found bodies pre- 

 cisely like the Leishmania donovani. He gave it the name Hel- 

 cosoma tropicum. The great similarity to the other organisms has 

 led more recent writers to identify it with Leishmania, but as it 

 induces a local and not a general infection like kala-azar, it is now 

 known as Leishmania furunculosa. 



Cultivation. — The organism has been cultivated. by Nicolle and 



Fig. 221. — Oriental sore (Wellcome Research Laboratory) . 



Manceaux§ upon the same media and in the same manner as 

 Leishmania donovani and Leishmania infantum with which these 

 investigators believe it to be identical. Cultivation was also success- 

 fully achieved by Row. 



Pathogenesis. — The virus is pathogenic for man, monkeys such 

 as Macacus simius, M. cynomolgus, M. rhesus and M. inuus, and for 

 dogs. The same effects are produced whether fresh virus from a 

 human ulcer, or from an artificial culture be employed. In dogs 

 the inoculations produce only nodular formations; in monkeys, 

 nodules like those in human beings that go on to ulceration. Intra- 

 peritoneal inoculations usually fail. The most successful inocula- 



* "Scientific Memoirs by Medical Officers of the Army in India," 1884, i. 

 t "British Med. Journal," Jan. 10, 1891, p. 60. 

 I Jour, of Med. Research," 1904, x, 472. 

 § Ann. de I'Inst. Pasteur," 1910, xxrv, 683. 



