Incidence of histoplasmin hypersensitivity in the Philippines

Long-term residents of the Philippines were skin tested with histoplasmin s kin test material. This study was conducted with 143 electric company (MERA LCO) employees from Manila, Philippines. We found that 37 (26 %) of the sub jects were skin test positive. Characteristics of the positive group were: average age of 37 years; all except one were lifelong inhabitants of Metro Manila; 25 were male and 12 were female; one-half of the subjects reported extended contact with chickens. Despite these findings, histoplasmosis is c onsidered to be a very rare disease in the Philippines. This survey indicat es that Histoplasma capsulatum is sufficiently present in the Philippines t o come in contact with one-fourth of the test population. This reinforces t he hypothesis that histoplasmosis is present in the Philippines and is prob ably being misdiagnosed as granulomatous-inducing diseases such as tubercul osis, e.g., so-called "drug resistant'' tuberculosis. We recommend larger s urveys of this type and attempts to culture the etiologic agent from natura l sources such as chicken and bat droppings.