EPA listed Balantidium as a Primary Pathogen in sludge Biosolids in 1989
21. Balantidium -------------------------------------- Balantidiasis
Balantidium: A genus of protozoa with cilia that includes Balantidium coli (B. coli). B. coli is the largest protozoan and the
only ciliate parasite to infect humans. The disease that B. coli causes is called balantidiasis. Clinical features, when
present, include persistent diarrhea, occasionally dysentery, abdominal pain, and weight loss. Symptoms can be severe
in debilitated persons.
B. coli is found worldwide. Because pigs are an animal reservoir for B. coli, human infections occur more frequently in
areas where pigs are raised. Other potential animal reservoirs include rodents and nonhuman primates. Humans most
often acquire the disease through ingestion of contaminated food or water
Diagnosis is based on detection of the parasite in stool specimens or in tissue collected during endoscopy. B. 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 iodoquinol and metronidazole as alternatives. Tetracyclines are contraindicated
in pregnancy and in children less than 8 years old.
From the Greek balantidion, meaning little bag.
SYNONYM OR CROSS REFERENCE: Balantidiosis, balantidiasis, balantidial dysentery
CHARACTERISTICS: Ciliated protozoa with a large, ovoid trophozoite 40-70 µm long, covered with cilia; contains both
macronucleus and micronucleus; cysts are usually 50-55 µm in diameter
SECTION II - HEALTH HAZARD
PATHOGENICITY: Infection of colon characterized by diarrhea or dysentery; accompanied by abdominal colic,
tenesmus, nausea, and vomiting with bloody and mucoid stools
EPIDEMIOLOGY: Worldwide; human infection rate is low; waterborne epidemics common in areas with poor sanitation or
environmental contamination with swine feces
HOST RANGE: Humans, other nonhuman primates and pigs
INFECTIOUS DOSE: Not known
MODE OF TRANSMISSION: Fecal-oral route; fecally contaminated water is a major mechanism of transmission
INCUBATION PERIOD: Usually 4-5 days
COMMUNICABILITY: As long as the illness persists