The use of the Kohn chlorazol black fixative-stain in an intestinal parasite survey in rural Costa Rica.

The Kohn one-solution chlorazol black (KCB) fixative-stain was used in the examination of stools from 162 children for intestinal parasites in rural, northern Costa Rica. Many more parasites were found by examining the stained smears than were seen on fresh smears. This was especially true of protozoan parasites. The advantages of the KCB technique are, as follows: (1) its simplicity; (2) the stability of the stain in solution and on slides; (3) the ability to use the stain with carbol-xylol in humid regions; and (4) the metachromatic qualities of the stain.