"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift

March 26, 2010

March 26 - Trichuris trichiura

Trichuris trichiura is a parasite found in human intestines. Also known as the human whipworm, this parasite’s adult and larval forms can live in the large intestine for up to 5 years, feeding on intestinal tissue secretions. These roundworms are pinkish-white in color and resemble a whip in shape and movement. Females lay 2,000-10,000 larvae per day, which are shed in human feces. With the right amount of moisture and warmth, in 2-3 weeks these eggs become infectious. Humans may become infected by accidental ingestion of eggs from fecal contaminated soil. Infectious eggs are sometimes found in water or in dry foods such as rice, grains, vegetables, and beans. Once ingested, the eggs hatch and burrow into the wall of the small intestine where they grow. About 300-500 million people are infected worldwide, mostly located in tropical places. Diagnosis occurs when eggs are observed in patients’ feces. Although rare in the U.S., people who do not dispose of human waste properly, have poor hygiene, and children playing in dirt contaminated with animal feces are especially prone to the disease. Recent studies have also shown that people with trait characteristics in chromosomes 9 and 18 may also be susceptible. Humans with over 100 parasites may have symptoms associated with intestinal disease. Very serious cases may cause diarrhea, vomiting, loss of appetite, constipation, blood loss, anemia, rectal prolapse, inflammatory and toxic damage to intestines. Medication as well as anti-parasitics are effective to promote healing.

Contributed by Allison Gittings, Bucknell University.
Image from the CDC Public Health Image Library.


  1. so the minimum number of parasites after which one gets symptoms is 100?

  2. I don't think it's a magic number of worms or anything...the student who wrote this was likely using the info from wikipedia that says that people with lower doses (<100) are rarely symptomatic.

  3. I am considering helminthic therapy using "Trichuris trichiura". I am already hosting 35 Necator americanus hookworms and trying to figure out how many whipworm ova to ingest to be safe. The problem is that not all the ova one ingests, actually reach maturity. Would you be able to shed any light onthe subject? Is there any research on this out there?

  4. Gosh - no idea. I'm sure a lot has been published on Trichuris, though.

  5. any chance you could look this up in an official source? I am wondering if 300 TT is a large number for a healthy adult with normal nutrition or is that high enough to cause disease.

  6. Think it's best for you to consult with an M.D. or helminth therapy professional.