A Clinical, Parasitologic, and Immunologic Study of Schistosomiasis in 103 Puerto Rican Males Residing in the United States

Abstract

In a study of 103 Puerto Rican prison inmates, using a variety of clinical and laboratory methods including serologic and skin tests, 29 (28%) were found to harbor Schistosoma mansoni. Skin tests revealed 45 (44%) positive. Evalua-tion of these individuals led to the following conclusions: (1) Chronic schistosomiasis, the form of the disease usually seen in the United States, is relatively asymptomatic, with few physical findings. (2) Schistosomiasis should be considered in any individual born or residing in Puerto Rico, since approximately one-third of the group was infected. (3) The skin test is a valuable screening test for active, and perhaps for light and terminated schistosomiasis. (4) Serologic procedures were evaluated, and a good correlation between serologic tests and parasitologic findings was found in the group positive for S. mansoni and in the negative group. Serologic tests in a group of 17 individuals, positive by skin tests and negative on parasitologic examination, revealed the presence of schistosomal antibodies. (5) In a group of 27 infected individuals, 42% demonstrated abnormal bromsul-falein retention, a greater number of positive cephalin flocculation reactions, elevated gamma globulin, and decreased albumin levels, by electrophoresis. Routine laboratory findings were of little aid in establishing a diagnosis. (6) A diagnosis of schistosomiasis should not be excluded unless a negative skin test, 2 or 3 negative stool examinations using concentration techniques, and a negative rectal biopsy have been obtained. (7) If the skin test is positive and eggs cannot be demonstrated by repeated stool examinations or by rectal biopsy, infection is probably light or has terminated, and treatment is probably not warranted. (8) If eggs are demonstrated, treatment should be initiated to minimize the hepatic-pulmonary complications of the infection.