Skin Sensitivity to Histoplasmin and Coccidioidin in Israel

Abstract

Summary Skin testing of 900 members of the Israeli Defense Forces and of workers at an archeologic dig at Massada was done using histoplasmin and coccidiodin, both in dilutions of 1–1000. No skin reactions were obtained in the archeologic workers. Three of the members of the Israeli Defense Forces had reactions to histoplasmin of 5 mm diameter or more and one reacted to coccidiodin in similar magnitude. However, 12 others had reactions to histoplasmin of 2 to 5 mm and 21 others had reactions to coccidioidin of 2 to 5 mm. Since the exposure to soil at Massada was intense, the negative skin tests seem to rule out this area as one contaminated with Histoplasma capsulatum or Coccidioides immitis. The paucity of strongly positive skin tests among the Army personnel indicates that Israeli soil does not contain H. capsulatum or C. immitis. The minimal skin reactions suggest the possibility, however, that the antigens may have been too weak (1–1000 dilution) and Israel may be an area of low but definite endemicity of infection with these two fungi.