Parasites (Worms)

Parasites are any of a number of worms or microscopic organisms that can infect humans. Many are transmitted by ingestion of contaminated food or water, although other modes of transmission are also possible.

Parasites are made up of eukaryotic cells similar to their human hosts, in contrast to bacteria that have distinctly different cells. This makes treatment of parasitic infections harder than the treatment of bacterial infections, since it is harder to find chemical agents that are toxic to the infective agent without also being toxic to the human host.

Many species of parasites are uncommon in North American populations but common in third world countries where sanitary conditions are poorer. However, with increased international travel, many parasites previously associated only with third world countries are showing up in North America, requiring a higher level of suspicion of parasites than in years past.

Please see conventional, complimentary and alternative medical treatments for important background information regarding the different types of medical treatments discussed on this page. Naturopathic, Complimentary and Alternative treatments that may be considered include:

• Gastrointestinal pain
• Diarrhea
• Nausea / reduced food intake
• Pruritus ani (especially pinworm)
• Intestinal obstruction (especially roundworm)
• Appendicitis (especially roundworm)
• Intestinal bleeding and anemia
• Malabsorption of nutrients and micronutrients
• Retardation of growth and cognitive development
• Surgical complications such as obstruction, rectal prolapse and abscess

Colonoscopy and biopsy.

•  >    Enterobius vermicularis (Pinworm):

  Perianal itching, intestinal abscesses and bleeding. Nematode infestation of the large intestine. Eggs may be found in the perianal area; they can be transferred with a cellophane tape swab to a slide for microscopic inspection. Worms may also be seen in stools, and sometimes around the anus.
•        Roundworms

  •  >    Ascaris lumbricoides

    Nematode infestation of the jejunum. May cause intestinal, biliary, or pancreatic obstruction; appendicitis. Eggs may be diagnosed by a simple smear of stools.
  •  >    Strongyloides stercoralis

    Roundworm that infests intestines and lungs. Most common in southern rural USA. Symptoms may include rash, pneumonia, diarrhea. May be life-threatening. DX: stool analysis.
  •  >    Trichinella spiralis

    Nematode worm found in undercooked meat, especially pork. Infestation may result in death within six weeks. DX: muscle biopsy to determine the presence of encysted larvae (stool analysis not useful).
  •  >    Trichuris trichiura

    (Whipworm) Nematode infestation of the large intestine. Symptoms include blood-streaked stools, rectal prolapse, iron-deficiency anemia, malnutrition. DX: stool analysis.
•        Tapeworms

  May be asymptomatic, but in some cases can cause intestinal obstruction, life-threatening liver and pericardium infestations, or seizures [Tabers2013]. DX: Eggs can be swabbed from perianal areas and examined, stool analysis.

  •  >   
    Diphyllobothrium latum (Flatworm)
  •  >   
    Taenia solium (Pork Tapeworm)
  •  >   
    Hymenolepis nana (Tapeworm)
  •  >   
    Echinococcus granulosus (Dog Tapeworm)
•        Hookworms

  •  >    Necator americanus

    (New World hookworm). Symptoms include iron-deficient anemia, physical and mental retardation, cardiac complications. DX: stool analysis.
  •  >    Ancylostoma duodenale

    (Old World hookworm)
•  >    Balantidium coli

  A ciliated protozoa that commonly infests the intestines of swine. May cause diarrhea, dysentery, vomiting, weakness, and occasional ulceration of the large intestine. DX: stool analysis.
•  >    Entamoeba histolytica

  Entamoeba histolytica and other amoebas cause irregular ulcers in the rectum with red borders and gray bases. May also invade the liver. DX: stool analysis, biopsy of ulcer, detection of antibodies in the blood. CT scan or ultrasound may reveal abscess due to liver involvement.
•  >    Giardia lamblia

  A flagellated protozoa that infests the small intestine. May cause diarrhea or dysentery. DX: stool analysis, stool antigen.
•  >    Fasciola hepatica

  (Liver Fluke) Trematode worm commonly infesting herbivores (cattle, sheep, etc.). Causes enlarged and painful liver, fever. DX: stool analysis.
•  >    Paragonimus westermani

  (Lung Fluke) Trematode worm commonly infesting dogs, cats, swine, crabs, and crayfish. Presentation may resemble TB.

• Pinworm (Enterobius vermicularis): Pyrantel pamoate, albendazole, mebendazole. Clean bed linens and house daily during treatment [Tabers2013].
• Roundworm (Ascaris lumbricoides): Pyrantel pamoate is the drug of choice, mebendazole is also effective [Tabers2013].
• Hookworm (Necator americanus, Ancylostomia duodenale, Strongyloides): Mebendazole, pyrantel pamoate. Iron supplementation for anemia [Tabers2013].
• Balantidium coli: Tetracyclines, metronidazole, paromomycin [Tabers2013].
• Entamoeba histolytica: Asymptomatic patients: paromomycin (500mg PO TID for 7 days) or iodoquinol (650mg PO TID for 20 days). Dysentery and liver abscesses are treated with metronidazole (750mg PO TID for 10 days) followed by iodoquinol (650mg PO TID for 20 days) [Tabers2013].
• Giardia lamblia: Metronidazole, albendazole [Tabers2013].
• Strongyloides stercoralis: Thiabendazole or mebendazole. Repeated courses of treatment may be necessary [Tabers2013].
• Tapeworm (Taenia spp., Diphyllobothrium latum, Hymenolepis spp., Echinococcus granulosus:
• Trichinella spiralis):
• Whipworm (Trichuris trichiura): Mebendazole is drug of choice, albendazole, ivermectin also useful [Tabers2013].
• Liver Fluke (Fasciola hepatica):
• Lung Fluke (Paragonimus spp.):