Histoplasmin skin tests were done on 1,021 persons in eight communities in western Colombia; reactor rates varied from 0 to 74%. Reported cases of histoplasmosis and other studies of histoplasmin sensitivity in Colombia are reviewed, and these suggest that the disease is endemic in the Pacific coastal plain, the Cauca and Magdalena valleys, and the eastern lowlands. The areas of high prevalence are characterized by altitudes below 5,000 feet, constant warm to hot temperatures, moderate to very heavy rainfall, and tropical or subtropical forest vegetation. It is suggested that low annual rainfall in the north coast and continual cool temperatures at altitudes above 6,000 feet are unfavorable for the growth of H. capsulatum and thus explain the low prevalence of histoplasmin sensitivity in these areas.
Formerly Fellow in Infectious Diseases, Departments of Pediatries and Epidemiology; present address, Middle America Research Unit, Box 2011, Balboa Heights, Canal Zone.
Formerly Assistant Professor of Epidemiology; present address, R.E.C.S. Unit, World Health Organization, Geneva.