Histoplasmin Skin Test

In a histoplasmin skin test survey of elementary school children in Frederick County, Md., the percentage of positive reactors was found to be 26.5% and 42.4% among 917 second graders and 1,007 sixth graders, respectively. These percentages were comparable to those obtained in studies of similar age groups in some areas of the Ohio and Mississippi River Valleys where histoplasmosis has long been known to be highly endemic. The present study and other accumulated data indicate that histoplasmosis is probably as prevalent in some of the Middle Atlantic states as in any other part of the country. Additional skin test surveys in other "nonendemic" areas might further modify the tenaciously held concept that histoplasmosis in the United States is limited to its Middle Western region.