The Importance of Fecal Examination in the Diagnosis of Strongyloidiasis
BETWEEN 1942 and 1952 there were 35 patients seen at the Clinic in whom diagnoses of infestation with Strongyloides stercoralis were made. This was the most commonly reported nematode, occurring slightly less than once in each thousand stools examined. This report summarizes the symptoms of which the infested patients complained, and emphasizes the importance of fecal examination in the diagnosis of this disease.
The life cycle of S. stercoralis is similar to that of the hookworm but is slightly more complicated. The filariform larvae develop in soil and infest the host by penetrating the skin, and eventually reach the intestines by way of the heart and lungs where they develop into adults. The adults mate, and the females penetrate the intestinal mucosa where the eggs are laid. These hatch into rhabditiform larvae which are released into the lumen of the intestines. Detection of the parasite depends upon observation of larvae in the feces. These forms are quite easy to identify because S. stercoralis is the only common parasite in which the ova hatch within the intestines. The larval form pass into the soil and the life cycle may then follow either of two courses. The rhabditiform larvae may develop directly into adults whose eggs hatch into more rhabditiform larvae which in turn can develop into adults. The second type of life cycle is the parasitic one in which the rhabditiform larvae develop into filariform larvae which have the power of infesting man. In man, furthermore, infestation is self-perpetuating because the. . .