Clinical Presentation of Balantidiasis


Most people who are infected with Balantidium coli remain asymptomatic.  An infected individual may have cysts or trophozoites in their feces, but be free of any other symptoms or complaints (See Diagnosis).


Note: consult a physician if you suspect you have Balantidiasis.



Although Balantidium coli usually resides in the lumen of its host, trophozoites can invade the mucosa of the large intestine (cecum and colon) and cause ulcerations.  The parasite secretes a substance called hyaluronidase enzyme, which helps degrade intestinal tissue and facilitates penetration of the mucosa.  Other bacteria in the intestine may enter the ulcer along with Balantidium coli, leading to secondary infections.  Ulcerations of the large intestine can be viewed using sigmoidoscopy (See Glossary).




Common symptoms of Balantidiasis include chronic diarrhea, occasional dysentery (diarrhea with passage of blood or mucus), nausea, foul breath, colitis (inflammation of the colon), abdominal pain, weight loss, deep intestinal ulcerations, and possibly perforation of the intestine.






Since these symptoms are non-specific and common to other conditions such as amebic dysentery or amebiasis, a diagnosis of Balantidiasis must be made by microscopic examination of stool or tissue sample (See Diagnosis).


Fulminating acute Balantidiasis is when the disease comes on suddenly and with great intensity.  Left untreated, it is reported to have a case fatality rate of 30%.  Dysentery due to hemorrhaging (bleeding) can lead to shock and death.  It is important to consider what other health conditions a patient might have that render them more vulnerable to severe Balantidiasis: for example, other intestinal infections or parasites, malnutrition, alcoholism, compromised immunity, or a history of chronic disabling diseases.  Infection may be more likely and symptoms are certainly more severe in debilitated individuals.  Unfortunately, poor overall health is a common trait of the populations most affected by Balantidium coli (See Epidemiology).


The symptoms described are for the acute cases that appear when Balantidium coli is invasive.  Most infections are asymptomatic.  Still, asymptomatic individuals can transmit the disease, which highlights the importance of Public Health Interventions.



Incubation period


After ingestion of an infective Balantidium coli cyst, days to weeks may pass before infection occurs.





The Parasite


Life Cycle


Animal Reservoirs

Clinical Presentation





Public Health Interventions


Glossary of terms

References and links