Dangerous Parasites: How a Nasty Job Keeps us Healthy

In this week’s episode of Taboo, the show explores the world of people who do jobs that most of us would never want to do, no matter the pay. Some of these jobs are so disgusting that they fall under the realm of taboo. However, some of these nasty jobs are incredibly important to society. Dwight Bowman, a parasitologist, works at a water treatment plant where he examines human waste looking for dangerous parasites that might be harmful to people. Without keeping these parasites in check, many of us could easily become sick. Here are a few parasites that parasitologists like Bowman monitor.


Remember all those warnings about never eating raw pork? There is a good reason for that, a nasty worm. Once a person consumes infected meat, the roundworm that causes Trichinosis hatches in the stomach and lodge in the intestine where the larvae mature into adult worms. The adults then produce larvae that migrate through various tissues, including muscle. Trichinosis can cause diarrhea, cramps, vomiting, muscle cramps, and high fever as well as other symptoms.

Trichinosis most often occurs when people eat undercooked pork or wild game. Infections occur primarily in rural areas and place where hog farming is common, but anyone can get the infection by eating contaminated meat. In the wild, animals pick up trichinosis when they feed on other infected animals. Omnivores in farm situations, like pigs, can become infected with trichinosis when they eat infected meat scraps. The increased regulation of pork feed in the United States has made infection in pigs less common source of infection, but parasitologists still watch closely for signs trichinosis contamination in our food supplies.


Ascariasis is the most common intestinal worm infection and is caused by consuming food or drink that contains eggs of this roundworm. Infections of ascariasis are most common places with poor sanitation or anywhere people are directly exposed to human waste, which carries the worm’s eggs.

Ascariasis worms have a particularly awful life-cycle. Once consumed, the eggs hatch and release larvae within the small intestine. The larvae then travels through the bloodstream to the lungs, exit up through the large airways of the lungs, and are swallowed back into the stomach and reach the small intestine. Sometimes people can suffer from a form of pneumonia during the worm’s travel through the lungs. Once in the small the intestine , the adult worms live for 10-24 months laying eggs which are present in the feces. Individuals who are infected may have many symptoms including coughing up blood, expelling worms from the nose and mouth and running a fever.


Live with dog and cats? Take care around their feces. Infected dogs and cats shed Toxocara eggs in their feces and the eggs may get into the soil. Accidental ingestion of Toxocara eggs may occur when children eat the infected dirt, when vegetables that grew in the soil are not cleaned or just incidentally. Once ingested the Toxocara eggs hatch, allowing roundworm larvae can travel in the bloodstream throughout body to places like the liver, heart, lungs, brain, muscles, and eyes. Heavy infections can cause damage to these tissues and organs. The symptoms of toxocariasis include fever, coughing, inflammation of the liver, and blindness.

All of these parasitic infections are still fairly common. If it wasn’t for parasitologist checking our waste material and our living environments to make sure that the parasites do not run rampant, we would have many more infections. You may not want to do this nasty job, but you should be glad that someone is willing to do it.

Tune in this Sunday July 29 at 10 et/pt and watch Taboo: Nasty jobs.


  1. Mitch Rohlman
    Celina, Ohio
    August 8, 2012, 5:46 am

    I have a few questions I would like to direct to Prof. Bowman. Can you return his email address? Thank You mr

  2. N.Jaankiramu
    Chhatisghar India
    January 11, 2013, 2:39 am

    I like many programes in National Geographic

  3. […] The coprolites also revealed that the Neanderthals apparently had parasites, such as hookworms and pinworms, similar to the ones afflicting modern and other ancient people. (Related: “Dangerous Parasites.”) […]

  4. Ned Boudreaux
    June 26, 2014, 11:29 am

    This article has a grammatical error in about every other paragraph. If you want to be taken seriously writing technical articles, be more careful.