BALANTIDIUM COLI

HANIF HAFIZ HANAFI 08-3-37

MORPHOLOGY

The parasite exists in two form, trophozoite and cyst. Trophozoites are oblong, spheroid, or slender. They are 30-50 microns long and 20-120 microns wide. They have two nucleus which are the macronucleus and a micronucleus. The macronucleus is sausage shaped while the micronucleus is smaller and hidden behind the macronucleus. The whole body is covered with fine cilia arrange in rows.

Two contractile vacuoles are located in the middle and posterior regions of the body. It has at anterior end and obliquely arranged depression, the peristome which may appear wide open or slit like, in the bottom of which is the cytostome. Food vacuoles contain erythrocytes, cell fragments, feces, and starch granules.

Cysts are smaller than trophozoites, they are found in faeces measuring 40-60 mm in diameter. Cysts are round and have a tough, heavy cyst wall made of one or two layers. Usually only the macronucleus and perhaps cilia and contractile vacuoles are visible in the cyst

MODE OF INFECTION

Infection occurs when the cyst, which is the infective stage is ingested in contaminated food or water.

PATHOGENESIS

Under ordinary conditions, the trophozoite feeds on the food debris in caecum, ingesting particles with cytosome. But sometimes, Balantidium coli produces proteolytic enzymes that break down and digest the intestinal epithelium leading to ulcer which may be variable in shape, flask shape, like amoebic ulcer.

BALANTIDIUM COLI

HANIF HAFIZ HANAFI 08-3-37

Colon ulceration develops which allows for infiltration by lymphocytes and polymorphonuclear leukocytes. Haemorrhaging and secondary bacterial infections will develop next. Perforation of the large intestine and appendix will occur followed by death. The liver or lung can be infected. Vaginal, uterine, and bladder infections have been associated with this parasite.

CLINICAL PICTURE Most people who are infected with Balantidium coli remain asymptomatic. An infected individual may have cysts or trophozoites in their faeces, but be free of any other symptoms or complaints. 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. 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

BALANTIDIUM COLI

HANIF HAFIZ HANAFI 08-3-37

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. 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.

DIAGNOSIS

Balantidiasis should be considered if the patient works closely with pigs or other livestock, lives in or has recently traveled to a region with poor water sanitation, or has had contact with infected persons.

Balantidiasis is diagnosed by microscopic examination of a patient’s feces. A stool sample is collected and a wet mount is prepared. Cysts or trophozoites can be detected in the feces. Balantidium coli is passed periodically, therefore stool samples should be collected frequently and examined immediately in order to make a definitive diagnosis.

Trophozoites can also be detected in tissue. In order to collect a tissue specimen from the large intestine, a sigmoidoscopy procedure is used. A sigmoidoscope is used to visually inspect the rectum and the sigmoid colon to look for bleeding, ulcers, and inflammation in order to diagnose the cause of diarrhoea and other GI complaints, and taking tissue biopsy for inspection.

BALANTIDIUM COLI

HANIF HAFIZ HANAFI 08-3-37

Since the symptoms of Balantidiasis are similar to those of amebiasis, it is important to identify the correct protozoan responsible for the disease. Microscopic examination of the stool or tissue sample and characterization of the organism according to morphology are needed to make the correct diagnosis. Balantidium coli is the largest protozoan and the only ciliate to parasitize humans. These traits can be of help when identifying organisms in samples from patients. Living trophozoites are yellow or green in color.

TABLE OF DIFFERENCE BETWEEN TROPHOZOITE & CYST OF BALANTIDIUM COLI

Trophozoite CystShape Oval, pointed at anterior end SphericalSize 50-130 mm long by 20-70 mm wide 40-60 mm acrossSurface Covered in cilia Covered with thick, hard cyst

wall with cilia sometimes visible underneath

Motility Rotary or boring motility, “like a thrown football”

Non-motile

Infectious Not infective InfectiveReproduction

By binary fission or conjugation Non-reproductive

Nuclei Macronucleus (kidney-shaped) and micronucleus (spherical, next to macronucleus) visible

Only macronucleus (kidney-shaped) visible; contractile vacuole visible in young cysts; in older cysts, organelle structures look granular

Important cell structures

Funnel-shaped cytostome (cell mouth) near anterior end; 2 contractile vacuoles

Cyst wall made of one or two layers

Diagnosis Occasionally found in feces, often found in tissue biopsies of infected individuals

Diagnostically found in feces of infected individuals