Most cases are asymptomatic.
Clinical manifestations, when present, include persistent diarrhea, occasionally dysentery, abdominal pain, and weight loss.
Symptoms can be severe in debilitated persons.
Diagnosis is based on detection
of trophozoites in stool specimens or in tissue collected during endoscopy.
Cysts are less
frequently encountered. Balantidium coli is passed intermittently and once
outside the colon is rapidly destroyed. Thus stool specimens should be collected
repeatedly, and immediately examined or preserved to enhance detection of the parasite.
The drug of choice
is tetracycline*, with metronidazole* and iodoquinol* as
alternatives. Tetracycline is contraindicated in pregnancy and in
children less than 8 years old.
* This drug is approved by the FDA, but considered investigational for this purpose.