Balantidiasis: what are the causes and symptoms of this intestinal disease?

Balantidiasis: what are the causes and symptoms of this intestinal disease?
Photo source: Getty images

Balantidiasis is a rare infectious disease of the human colon and digestive tract. What causes balantidiasis, what are its first symptoms and treatment options?


Balantidiosis is the name of the disease that originates from the causative agent of the disease, the parasite Balantidium coli. It is a rare disease with a worldwide distribution, which mainly affects the human large intestine.

The characteristics of the disease, symptoms, diagnosis, current treatment options and many other interesting information can be found in this article.

A rare infectious disease caused by a parasite, a special protozoan called the intestinal fluke - Balantidium coli. It is an intestinal infection that affects the large intestine, causing an inflammatory process and the formation of specific deep ulcers.

If balantidiasis is left untreated, there is a risk of gastrointestinal bleeding, rupture (perforation) of the intestine and peritonitis.

Balantidium coli has two basic forms - a non-infectious motile form and a highly infectious non-mobile form affecting the colon.

The non-infectious form, called the trophozoite, is the motile, oval to ovoid-shaped stage of the protozoan. In contrast, the more dangerous infectious form of the funnel cyst is the non-mobile, characteristically round-shaped form, also called the cyst form.

When the intestinal pox enters the human body, it establishes itself in the large intestine in the digestive tract. It produces toxic substances for the body, which affects the development of health problems - especially those of digestion and excretion.

The protozoan invades the human colon and the resulting cysts cause an inflammatory process in the colon, bleeding and, at a later stage, the gradual formation of deep ulcers in the area.

Important substances are removed from the individual's digestive tract, such as sugars, fats, proteins and important vitamins and minerals.

Balantidium coli can cause the secretion of toxins that irritate the intestinal tract and the inner intestinal wall. The consequence is a reduced absorptive (absorption) capacity of the digestive tract - and therefore a reduced function of absorbing the necessary nutrients into the body.

Typical symptoms are diarrhea and stools with a mixture of blood and mucus.

The course of balantidiasis is particularly severe in people with weakened immune systems (for example, individuals affected by HIV or AIDS).

Common symptoms include nausea, lack of appetite, abdominal pain or diarrhoea and bloody stools. However, there are also cases where the disease is mostly asymptomatic with no obvious outward manifestations.


As mentioned above, the causative agent of infection is the protozoan funnel cyst Balantidium coli. This parasite mainly affects pigs, but can also infect humans through sick animals or contamination of meat or water.

The source of infection is therefore mainly the domestic pig. The parasite was first discovered in 1857.

Balantidium coli is a common parasite of wild and domestic pigs, cattle and monkeys in tropical countries. Balantidium coli lives in the animal's large intestine as a commensal (a harmless parasite that feeds on its host's leftover food).

The disease is more common in subtropical to tropical areas. Outside these areas, people working with pigs, cattle and food are the most at risk.

The disease is transmitted to humans through direct or indirect contact with pig faeces.

Humans become infected with the parasite mainly through contaminated hands, water or food.

The disease is therefore also transmitted through poor hygiene and failure to observe occupational hygiene precautions.

Balantidium coli - a parasite infecting the large intestine of the human digestive tract
Balantidium coli - a parasite infecting the large intestine of the human digestive tract. Source: Getty Images


Bloody stools and diarrhoea (watery/sparse stools) are characteristic of the more severe stage of the disease. However, diarrhoea, abdominal pain, nausea, lack of appetite and vomiting are common symptoms.

In healthy people, the course of the disease is often mild to asymptomatic.

Associated symptoms include headache, increased fatigue, general exhaustion, malaise, increased temperature and weight loss.

The risk is dehydration of the body due to diarrhoea and vomiting.

Possible symptoms and manifestations of balantidiasis:

  • Diarrhoea (loose/watery stools)
  • Indigestion
  • Blood in stool
  • Mucus in stool
  • Nausea and vomiting
  • Nausea
  • Increased fatigue and general weakness
  • Malaise and exhaustion
  • Abdominal pain
  • Headache
  • Decrease in body weight
  • Dehydration (water loss)
  • Increased body temperature
  • Insomnia


The diagnostic procedure consists of taking a comprehensive history of the patient and identifying both subjective and objective clinical symptoms. Occupational history is also important, as is the identification of potential contact with contaminated products or animals.

A fresh stool sample is taken from the patient, which is examined and evaluated in the laboratory with the aim of identifying the specific causative agent and clinical signs.

In some cases, a biopsy is indicated where a small tissue sample is taken locally directly from the colon from the intestinal mucosa (special scraping).

Additional examinations by a gastrointestinologist (palpation, colonoscopy or other physical imaging) are possible.

Interdisciplinary collaboration between the examining physician (gastrointestinologist) and the microbiologist and infectologist is appropriate.

The aim of the examination is to demonstrate the presence of the parasite Balantidium coli in the stool or intestinal mucosa, and by differential diagnosis it is possible to confirm or exclude the disease of balantidiasis.

After cure and improvement of clinical symptoms, it is advisable to recheck and exclude the presence of residual balantidiasis infection in the patient's organism by biological examination of the stool.

How it is treated: Balantidiosis

Treatment options for balantidiasis: drugs, antibiotics, diet and drinking regime

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Interesting resources

  • MARTÍNEK, Jan and Pavel TRUNEČKA. Gastroenterology and hepatology in algorithms. Prague: Maxdorf, [2021]. Jessenius. ISBN 978-80-7345-684-9
  • - What is Balantidiasis? News Medical Life Sciences. Emily Henderson B.Sc.
  • - Balantidiasis. Sciencedirect online
  • - Balantidiasis. Emedicine - Medscape online