Table of Contents
Definition / general | Epidemiology | Pathophysiology | Diagrams / tables | Clinical features | Diagnosis | Case reports | Treatment | Microscopic (histologic) description | Microscopic (histologic) images | Electron microscopy description | Differential diagnosis | Additional referencesCite this page: Weisenberg E. Balantidiasis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colonbalantidiasis.html. Accessed October 2nd, 2023.
Definition / general
- Disease caused by the ciliate protozoan Balantidium coli
Epidemiology
- B. coli is found worldwide, but disease occurs most commonly in parts of the developing world including Latin America, Southeast Asia, Papua New Guinea and parts of the Middle East
- Estimated prevalence is 1% in Aymara children in northern Bolivia (Am J Trop Med Hyg 1998;59:922);and 0.4% in rural northeast Thailand (Korean J Parasitol 2013;51:727)
- Very low prevalence in industrialized countries
- Humans are usually resistant to infection; disease generally occurs in debilitated or poorly nourished patients
- Pigs are the primary reservoir for human infection and most cases occur in people in close proximity to pigs, although rats and other mammals may also transmit disease
- Human to human transmission is also described
- Infection by ingesting fecally contaminated food or water or from ingesting cysts due to other direct contact with pig or rat excrement
Pathophysiology
- Excystation occurs in the small intestine and trophozoites migrate to the colon
- Invasion into the intestinal wall occurs, where they multiply and cyst formation occurs
Clinical features
- Most infections are asymptomatic
- Symptomatic patients generally suffer disease similar to amebiasis, with diarrhea, dysentery, abdominal pain and weight loss
- Chronic disease is most common, although fulminant colitis may occur, including perforation leading to peritonitis
- Disease in the lung, urinary bladder and bone has been described (see case reports)
- Similarly to E. histolytica, B. coli causes flask shaped ulcers in the large intestine, most commonly in the cecum and rectosigmoid
- Neobalantidium coli is the largest protozoan parasite and only pathogenic ciliate to infect humans (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 532 [Accessed 23 August 2019])
Diagnosis
- Diagnosis is usually made by identification of mobile trophozoites in fresh stool or scraped from an ulcer seen during endoscopy
- Rarely the diagnosis is made by examination of urine or bronchioalveolar lavage fluid, or by identification in biopsy or resection specimens
Case reports
- 20 year old man with pulmonary hemorrhage (S Afr Med J 2010;100:534)
- 28 year old man with dysentery (New Microbiol 2013;36:203)
- 47 year old woman with dysentery and non-Hodgkin lymphoma (World J Gastroenterol 2004;10:458)
- 60 year old man with vertebral osteomyelitis and myelopathy (J Neurosurg Spine 2013;18:310)
- 68 year old man with urinary balantidiasis (Trop Parasitol 2014;4:47)
- 72 year old woman with Balantidium coli in urine sediment (J Parasit Dis 2013;37:283)
- Causing severe peritonitis (Eur J Clin Microbiol Infect Dis 2004;23:393)
Treatment
- Tetracycline is the drug of choice
- Alternative treatments include metronidazole, ampicillin, iodoquinol and nitazoxanide
- Longer treatment is necessary if immunosuppressed
Microscopic (histologic) description
- The trophozoite is oval and large, sometimes large enough to be seen without magnification (generally 30-150 μm in length x 20-120 μm in width, rarely up to 200 μm in length), contains circumferential cilia (B. coli is the only ciliated parasite that infects humans)
- It is rapidly mobile
- In tissue sections, the trophozoites are large with kidney-bean shaped nuclei and visible cilia
- Cytostome (oral groove) can be seen on trophozoite (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 532 [Accessed 23 August 2019])
- N. coli cysts may be mistaken for helminth eggs (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 532 [Accessed 23 August 2019])
Microscopic (histologic) images
Electron microscopy description
- Flattened oval organism covered with cilia with gullet at anterior end
Differential diagnosis