Parasites come in many shapes and forms. They may be found on the skin, in the hair, in the muscles, blood, liver, lungs, bladder, and in the intestinal tract. In some third world countries, it is a leading cause of sickness and death. In the U.S., there is a misconception that intestinal parasites are rare and, therefore, parasitology tests are usually not ordered. Most intestinal infections come from contaminated food and water. In any immunocompromised patients, parasites are very common.

The specimen should be collected in special containers supplied and three specimens submitted. Most positive results are obtained from diarrhea specimens before any antidiarrheal or antiparasitic therapy. The specimens are examined for ova and parasites as well as IFA tests for Cryptosporidium and Giardia lamblia.

The principle for ova and parasites is by iodine/saline and trichrome staining. The principle for Cryptosporidium and Giardia is antigen staining with specific antibodies and IFA.

The normal results should be Negative for all tests.

Selected references:

1. Davidson, R.A. Issues in clinical parasitology: The treatment for giardiasis. Am J Gastroent. 1984; 79: 256-261.
2. Pickering, L.K., Woodward, W.E., DuPont, H.L. et al. Occurrence of Giardia lamblia in children in daycare centers. J Ped. 1984;104:522-526.
3. Orenstein, J.M., chiang, J., Steinberg, W., et al. Intestinal microsporidiosis as a cause of diarrhea in human immunodeficiency virus-infected patients-a report of 20 cases. Hum Pathol,1990; 21:475-481.
4. Editorial: Blastocystis hominis: commensal or pathogen? The Lancet. 1991; 337:521-522.