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For further information, see CMDT Part 35-11: Other Intestinal Flagellate Infections

Key Features

  • Balantidium coli is a large intestinal protozoan found worldwide but particularly in the tropics

  • Pigs are the reservoir host

  • Disease is rare in humans and results from ingestion of cysts passed in stools of humans or swine

  • Deaths have occurred from intestinal perforation and hemorrhage

Clinical Findings

  • Many infections are asymptomatic

  • Chronic infections may cause recurrent diarrhea or dysentery

  • Abscesses and ulcerations result from trophozoite invading the intestinal mucosa


  • Established by finding trophozoites or cysts in stool or ulcer scrapings of large bowel


  • Tetracycline hydrochloride

    • Treatment of choice

    • 500 mg orally four times daily for 10 days

  • Iodoquinol (diiodohydroxyquin)

    • Alternative drug

    • 650 mg orally three times daily for 21 days

  • Occasional success has also been reported with

    • Metronidazole

    • Paromomycin

    • Nitazoxanide

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