Microscopic Examination for Intestinal Parasites of 73 Boys

In March, 1929, a letter was received by the Director of the Hygienic Laboratory of the U.S. Public Health Service from the physician in charge of the National Training School for Boys, Washington, D.C., requesting that the southern boys in the latter institution be examined for hookworms. This Institution is a school for boys who have been apprehended for violation of Federal Laws, and the boys from the southern states constitute about 20% of the inmates, The request was referred to Dr. C.W. Stiles, Chief of the Division of Zoology of the Hygienic Laboratory, and the study was started under his direction in October, 1929.The request by the physician of the Institution was obviously based on the practical clinical point of view. He wished to obtain definite data which might be of value in interpreting the condition of these boys, many of whom came from the hookworm belt of the country, and who would consequently be likely to harbor this parasite, His inference in regard to hookworm infection proved correct, as the examinations disclosed that 34.2% of the boys were infected with hookworms. This figure compares favorably with one obtained by the Rockefeller Foundation, in an examination of 1,413,000 people of the southern states for the years 1910-1921, when a hookworm Infection of 36.7% was found. The findings in the present report supported the clinical appearance in at least some of the hookworm cases.The present survey, however, was not confined to hookworms alone, but a complete examination for all intestinal parasites was made. With few exceptions, this laboratory rarely makes examinations for one specific parasite, for complications may arise if a mixed infection is present. For example, if both hookworms and ascarids are present in the same patient, certain precautions are necessary in drug administration. If Strongyloides and hookworms are present a treatment for hookworms alone might be confusing as all of the symptoms would not disappear with the elimination of the hookworms. Further, academic and practical points arise in all examinations of this kind which make a general examination for all parasites desirable.With this purpose in view an examination for all intestinal parasites was started and has continued up to the present time. A complete single microscopic examination, for protozoa and for ova and larvae of worms, was made of one fecal specimen from each boy. Since only one specimen was examined from each boy, undoubtedly many infections (especially of protozoa) remained undetected. Statistics indicate that with certain parasites, such as Endamoeba histolytica, examination of one fecal specimen uncovers only about one-third of the infections, and that to uncover from 90% to 100% of the infections at least six specimens must be examined.