You are in: eMedicine Specialties > Infectious Diseases > MEDICAL TOPICS BalantidiasisArticle Last Updated: Feb 5, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Valda M Chijide, MD, Clinical Professor, Department of Medicine, University of Saskatchewan, Consultant in Infectious Diseases, Regina, Saskatchewan, Canada Valda M Chijide is a member of the following medical societies: American College of Chest Physicians and Infectious Diseases Society of America Editors: Jeffrey D Band, MD, Clinical Professor of Medicine, Wayne State University School of Medicine; Director, Division of Infectious Diseases and International Medicine, William Beaumont Hospital Corporation; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Ronald A Greenfield, MD, Professor, Chief, Department of Internal Medicine, Section of Infectious Diseases, University of Oklahoma College of Medicine; Eleftherios Mylonakis, MD, Clinical and Research Fellow, Department of Internal Medicine, Division of Infectious Diseases, Massachusetts General Hospital; Burke A Cunha, MD, Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital Author and Editor Disclosure Synonyms and related keywords: balantidiasis, balantidiosis, Balantidium coli, B coli, hyaluronidase, colon cyst, diarrhea, gastrointestinal infection, GI infection, infection associated with pig contact INTRODUCTIONSection 2 of 11
  BackgroundBalantidium coli is a ciliated protozoan, and it is also the largest human protozoan. It is known to parasitize the colon, and pigs may be its primary reservoir. PathophysiologyB coli occurs as a trophozoite and a cyst in the colon. The trophozoites replicate by binary fission and conjugation, and they subsist on bacteria. Humans ingest infective cysts, which then migrate to the large intestine, cecum, and terminal ileum. The organisms primarily dwell in the lumen, but they also can penetrate the mucosa and cause ulcers. Hyaluronidase is produced by this organism, which may enhance its ability to invade the mucosa. FrequencyUnited StatesB coli has a worldwide distribution with an estimated prevalence of 1%. Epidemics have occurred in psychiatric hospitals in the United States. InternationalInfection tends to be more common among humans who handle pigs. It is reported most commonly in Latin America; Southeast Asia; and Papua, New Guinea. In 1971, an outbreak involving 100 people occurred in Truk following a typhoon. Mortality/MorbidityMost infections in immunocompetent individuals are asymptomatic. The mortality rate for the acute and fulminating types was reportedly as high as 30% in untreated patients prior to the introduction of antibiotics. Pneumonia has been described in patients with cancer-related immunosuppression and has not always been associated with direct contact with pigs. CLINICALSection 3 of 11
HistorySome patients may develop the following symptoms:
PhysicalPatients may present with abdominal tenderness and, in cases with prolonged diarrhea, signs of dehydration. CausesThe risk of balantidiasis increases when the patient has contact with pigs, handles fertilizer contaminated with pig excrement, or lives in areas where the water supply may be contaminated by the excrement of infected animals. Poor nutrition, achlorhydria, and immunosuppression can be contributing factors. DIFFERENTIALSSection 4 of 11
Pneumonia, Fungal
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| Drug Name | Tetracycline (Sumycin) |
|---|---|
| Description | Isolated from a strain of Streptomyces aureofaciens. Exerts a bacteriostatic effect by reversibly binding to 30S and 50S ribosomal subunits of susceptible organisms, thereby inhibiting protein synthesis. |
| Adult Dose | 500 mg PO qid for 10 d |
| Pediatric Dose | <8 years: Not recommended >8 years: 40 mg/kg/d PO divided qid for 10 d; not to exceed 2 g/d PO |
| Contraindications | Documented hypersensitivity; breastfeeding; children <8 y; renal or hepatic impairment |
| Interactions | Decreases effect of penicillin; colestipol, divalent/trivalent cation–containing antacids, food, dairy products, and supplements decrease absorption; increases anticoagulant effect of warfarin; decreases efficacy of oral contraceptives; increases serum levels of digoxin and lithium; concurrent use of retinoids can increase risk of pseudotumor cerebri; tetracyclines may reduce insulin requirements |
| Pregnancy | D - Unsafe in pregnancy |
| Precautions | Photosensitivity may occur with prolonged exposure to sunlight or tanning equipment; reduce dose in renal impairment; consider drug serum level determinations in prolonged therapy; tetracycline use during tooth development (last half of pregnancy through age 8 y) can cause permanent discoloration of teeth; Fanconi-like syndrome may occur with outdated tetracycline; some patients experience headache, light-headedness, dizziness, or vertigo |
| Drug Name | Metronidazole (Flagyl) |
|---|---|
| Description | Synthetic drug with antiprotozoal and antibacterial action used to treat symptomatic patients with diarrhea. |
| Adult Dose | 500 mg PO tid for 5 d |
| Pediatric Dose | 35-50 mg/kg/d PO divided tid for 5 d |
| Contraindications | Documented hypersensitivity to metronidazole or other nitroimidazole derivatives; first trimester of pregnancy; history of blood dyscrasias |
| Interactions | Alcohol intake during and for 3 d after therapy induces disulfiramlike reaction; microsomal enzyme inducers (eg, phenytoin, phenobarbital) decrease serum levels; microsomal enzyme inhibitors (eg, cimetidine) prolong half-life; increases serum lithium levels and/or lithium toxicity |
| Pregnancy | B - Usually safe but benefits must outweigh the risks. |
| Precautions | Adjust dose in hepatic disease; monitor for seizures and development of peripheral neuropathy |
| Drug Name | Iodoquinol (Yodoxin) |
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| Description | Contact amebicide works in the lumen of intestine. |
| Adult Dose | 650 mg PO tid for 20 d |
| Pediatric Dose | 40 mg/kg/d PO divided tid for 20 d |
| Contraindications | Documented sensitivity; hepatic insufficiency; iodine intolerance |
| Interactions | Increases protein-bound serum iodine concentration |
| Pregnancy | C - Safety for use during pregnancy has not been established. |
| Precautions | GI distress, acneform and bullous eruptions, optic neuritis, optic atrophy, peripheral neuropathy, and thyroid dysfunction may occur; avoid long-term therapy |
| Media file 1: Trophozoite of Balantidium coli in colon. This photograph shows the large macronucleus and the thin cell membrane covered with cilia (X820). Courtesy of Armed Forces Institute of Pathology (AFIP 75-9300). | |
 | View Full Size Image | Media type: Photo |
| Media file 2: Cyst of Balantidium coli in feces. This photograph demonstrates a thick cyst wall and a large macronucleus (X820). Courtesy Armed Forces Institute of Pathology (AFIP 75-9301). | |
 | View Full Size Image | Media type: Photo |
Article Last Updated: Feb 5, 2007
