RAPID METHOD FOR DETECTION OF OVA OF INTESTINAL PARASITES IN HUMAN STOOLS
Authors: CHARLES A. KOFOID
Journal: JAMA (1918)

The military significance of infection by hookworm disease among recruits and troops of the United States Army might be inferred from its known clinical symp- toms.That it is characterized by anemia, edema, intes- tinal disturbances and by a disinclination to physical effort is well known.Testimony and statistics add to these charges the facts that morbidity and mor- tality tend to be higher among troops from the area of hookworm infection than among those from out- side that area.Comparisons of the records of exam- inations of new recruits from the hookworm area1 reveal the fact that white men with this infection make lower records than do the noninfected, literate and illiterate.There is also some evidence that hookworm infections tend to impede the progress of recruits in discipline and instruction.The guard house, venereal isolation camp and the hospital show higher rates of infection than does the camp as a whole.Hookworm disease appears to be one of the causes tending to increase the ratio of noninfectives among our troops and to lower the standard of their efficiency.Because of the numbers to be examined, the nature of the available equipment and the desirability of not encroaching on the duties of a medical staff already occupied with more important work, it was essential that any method used in detecting this infection should be rapid, accurate, simple, adapted to the utilization of a changing personnel in large part, and that it should not require elaborate apparatus or extensive laboratory equipment. COMPARISON OF VARIOUS METHODSThe direct microscopic examination of a small sam- ple of the fecal specimen is inaccurate because of the minuteness of the sample used, and impracticable because of the length of time required to make a fair examination.The greater efficacy of the brine flota- tion-loop method in the detection of worm ova as compared with the ordinary smear method is shown in the accompanying table, in which nine-day periods are compared.The salt flotation method is obviously inferior in the detection of Strongyloides.Only hospital cases, based on records at Camp Jackson, are included in the table.The great vari- ability in the daily hookworm precentages is probably due to the varying proportions of patients from the Northern states.The centrifuge method is at once precluded by the difficulty, if not impossibility, of securing an adequate number of instruments to accomplish a work of such magnitude, and the added difficulty of securing the requisite tubes and other glassware essential to equip 1.By Capt.P. F. Pittenger of the psychologic board at Camp Travis.and maintain facilities adequate to care for the number of examinations to be made.It also calls for extraordinary care in cleaning the glassware used, for hook- worm eggs are quite adhesive to the surface of glass.This is a difficulty of considerable importance when laboratory helpers are inexperienced, and adds much to the burden of supervision.The centrifuge is also inaccurate, probably because of the small size of the samples used.The standard fecal sample collected for this method in the Army is contained in a 2-dram vial.Negatives for hookworm by this method as used by the senior author in the Department Laboratory of the Southern Department were examined by the salt flotation method by us and found in about fifty examinations to show a 40 per cent, increase in infections.That is, the percentage was increased from 10 to 14.This was borne out