In diagnosing intestinal parasites, we may use various methods, but the best method is undoubtedly that of a microscopic examination of the feces.
DIAGNOSIS BY SYMPTOMS.
The practitioner who relies on symptoms alone for his diagnosis will undoubtedly often successfully recognize the true nature of the trouble, especially in severe infections. For instance, when we are in the infected area of hookworm disease and meet a typical clay-eater we note a complex of symptoms which is quite characteristic, and in most cases of this kind a microscopic examination seems unnecessary. In numerous medium cases and in practically all light cases of this disease however, a diagnosis on symptoms alone is uncertain unless we find severe cases, such as clay-eaters, in th same family. Outside of the infected area, probably few physicians would care to risk a definite diagnosis of this disease on symptoms alone even in the severe cases, while
STILES CW. CLINICAL DIAGNOSIS OF INTESTINAL PARASITES.. JAMA. 1903;XLI(3):172–173. doi:10.1001/jama.1903.04500010028008