Balantidium coli

Jump to navigation Jump to search
Balantidium coli
Scientific classification
Domain: Eukaryota
(unranked) Alveolata
Phylum: Ciliophora
Class: Litostomatea
Order: Vestibuliferida
Family: Balantiididae
Genus: Balantidium
Species: B. coli
Binomial name
Balantidium coli
(Malmsten, 1857)

WikiDoc Resources for Balantidium coli


Most recent articles on Balantidium coli

Most cited articles on Balantidium coli

Review articles on Balantidium coli

Articles on Balantidium coli in N Eng J Med, Lancet, BMJ


Powerpoint slides on Balantidium coli

Images of Balantidium coli

Photos of Balantidium coli

Podcasts & MP3s on Balantidium coli

Videos on Balantidium coli

Evidence Based Medicine

Cochrane Collaboration on Balantidium coli

Bandolier on Balantidium coli

TRIP on Balantidium coli

Clinical Trials

Ongoing Trials on Balantidium coli at Clinical

Trial results on Balantidium coli

Clinical Trials on Balantidium coli at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Balantidium coli

NICE Guidance on Balantidium coli


FDA on Balantidium coli

CDC on Balantidium coli


Books on Balantidium coli


Balantidium coli in the news

Be alerted to news on Balantidium coli

News trends on Balantidium coli


Blogs on Balantidium coli


Definitions of Balantidium coli

Patient Resources / Community

Patient resources on Balantidium coli

Discussion groups on Balantidium coli

Patient Handouts on Balantidium coli

Directions to Hospitals Treating Balantidium coli

Risk calculators and risk factors for Balantidium coli

Healthcare Provider Resources

Symptoms of Balantidium coli

Causes & Risk Factors for Balantidium coli

Diagnostic studies for Balantidium coli

Treatment of Balantidium coli

Continuing Medical Education (CME)

CME Programs on Balantidium coli


Balantidium coli en Espanol

Balantidium coli en Francais


Balantidium coli in the Marketplace

Patents on Balantidium coli

Experimental / Informatics

List of terms related to Balantidium coli

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Tamar Sifri [2]


Balantidium coli is a species of ciliate protozoan. This parasite is the only member of this family known to be pathogenic to humans. Hosts include pigs, wild boars, rats, primates (including humans), horses, cattle and guinea pigs. Infection is transmitted within or between these species by fecal-oral transmission. Pigs are the most significant reservoir hosts, though they show few if any symptoms.

Cysts are the infective stage, responsible for transmission of balantidiasis. The host usually acquires cysts through ingestion of contaminated food or water. Following ingestion, excystation occurs in the small intestine, and the trophozoites colonize the large intestine. Both cysts and trophozoites are identifiable by a large, "sausage shaped" macronucleus.

Balantidium coli as seen in a wet mount of a stool specimen. The organism is surrounded by cilia

The trophozoites reside in the lumen of the large intestine, where they replicate by transverse binary fission, during which conjugation may occur. Some trophozoites invade the wall of the colon using proteolytic enzymes and multiply; some of these return to the lumen. In the lumen Trophozoites may disintegrate or undergo encystation. Encystation is trigerred by dehydration of the intestinal contents and usually occurs in the distal large intestine, but may also occur outside of the host in feces. Symptoms can be local due to involvement of the intestinal mucosa, or systemic in nature and include diarrhea. Balantidiasis can be treated with carbarsone, tetracycline, or diiodohydroxyquin.

Geographic distribution

B. coli can be found worldwide. Pigs are a reservoir. Infection of people occurs more frequently in areas where pigs comingle with people, including the Philippines, Mexico, South America, and Papua New Guinea.

Less than 1% of the human population is infected worldwide.

Life Cycle

Cysts are the parasite stage responsible for transmission of balantidiasis (1). The host most often acquires the cyst through ingestion of contaminated food or water (2). Following ingestion, excystation occurs in the small intestine, and the trophozoites colonize the large intestine (3). The trophozoites reside in the lumen of the large intestine of humans and animals, where they replicate by binary fission, during which conjugation may occur (4). Trophozoites undergo encystation to produce infective cysts (5). Some trophozoites invade the wall of the colon and multiply. Some return to the lumen and disintegrate. Mature cysts are passed with feces (1).


Antimicrobial Regimen

  • Balantidium coli treatment[1]
  • Adult dosage:
  • Pediatric dosage:
  • Preferred regimen: Metronidazole 35-50 mg/kg/day PO in three doses (maximum dosage: 2 g) for 5 days, Tetracycline 40 mg/kg/dose PO in four doses for 10 days.
  • Alternative regimen: Iodoquinol 40 mg/kg/dose PO in three doses for 20 days AND Doxycycline.
  • Note: Nitazoxanide, a broad-spectrum antiparasitic and antihelminthic drug, may be another treatment for balantidiosis.


  1. Schuster FL, Ramirez-Avila L (2008). "Current world status of Balantidium coli". Clin Microbiol Rev. 21 (4): 626–38. doi:10.1128/CMR.00021-08. PMC 2570149. PMID 18854484.

Template:WikiDoc Sources