204 An Introduction to Medical Mycology 



(a) Historical survey.— The first case of this disorder was described 

 in 1906 by Darling, who was searching for cases of leishmaniasis in the 

 Panama Canal Zone. He considered the causative micro-organism to be a 

 protozoan parasite and named it Histoplasma capsulatum. Rocha-Lima is 

 given credit for first proving the causative micro-organism to be a fungus. 

 DeMonbreun and later Conant as well as others verified this fact and 

 worked out the life cycle of the fungus. Meleney reviewed the subject in a 

 comprehensive monograph. In a later short discussion ( 1942 ) he stated 

 that 47 human cases have so far been described. 



(b) Etiology.— The causative micro-organism, H. capsulatum, may be 

 discovered by direct examination or culture of the circulating blood, sputum 

 or feces, by spleen, liver or lymph node puncture, or may be recognized 

 in a biopsy section. According to Meleney, the fungus probably exists sapro- 

 phytically in nature. Cases have been reported from widely separated 

 geographic sites. No age is exempt and infants and children seem particu- 

 larly susceptible. A dog and a ferret have been found suffering from the 

 disease. Human subjects with the disease have all come from small towns or 

 farms. The portal of entry may be the lungs, the gastrointestinal tract or 

 an abrasion of the skin ( Meleney ) . 



(c) Symptoms.— The classic manifestations are hepatosplenomegaly, sep- 

 tic temperature, anemia, leukopenia and progressive loss of weight. Lymph 

 node enlargement may be the predominant feature affecting these struc- 

 tures in the palpable regions, mesentery, intestines and lungs. The bone 

 marrow may be involved early in the course of the disease. In children the 

 first evidence of the disorder may be related to the gastrointestinal tract 

 with nausea and diarrhea. The other symptoms then gradually appear. In 

 general, the disease runs a more rapid course in children than in adults. The 

 chief lesion may be ulcerative enteritis, as in the case reported by Hender- 

 son, Pinkerton and Moore. Pulmonary tuberculosis is frequently found as a 

 concomitant infection. The lungs may be either primarily or secondarily 

 affected and very occasionally are the only site of the disease. When the 

 infection becomes generalized the lungs are almost always involved. Bone 

 lesions and adrenal invasion have been reported. There may be ulcerative 

 lesions of the skin, tongue, nasopharynx or larynx. Purpura has been de- 

 scribed, as have papules, plaques, abscesses and patches of dermatitis. Pal- 

 mer, Amolsch and Shaffer reported an unusual case in which there was 

 mucocutaneous involvement resembling leishmaniasis. Palmer believes that 

 a mild subclinical infection with H. capsulatum is prevalent in certain 

 parts of the country. This explains the finding of pulmonary calcification 

 in patients showing negative reactions to tuberculin and coccidioidin, par- 

 ticularly since many of these patients react to histoplasmin. Christie and 



