Balantidium coli Overview
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Questions and Answers

What primary factors predispose a host to clinical disease caused by B. coli?

  • Malnourishment and antibiotic use
  • Malnourishment and concurrent infections (correct)
  • Concurrent infections and high antibiotic resistance
  • Improper sanitation and nutritional supplements
  • Which of the following clinical features is most characteristic of balantidiasis?

  • Continuous high fever with rash
  • Chronic fatigue and muscle pains
  • Weight loss and muscle wasting
  • Diarrhea alternating with constipation (correct)
  • Which method is least effective for diagnosing B. coli infection when stool examination yields negative results?

  • Biopsy of intestinal tissue
  • Stool examination for trophozoites and cysts
  • Imaging techniques like X-rays (correct)
  • Stool culture in specialized media
  • Which of the following treatments is the standard choice for B. coli infections?

    <p>Tetracycline at 500 mg, 4 times daily (C)</p> Signup and view all the answers

    What is the primary method of preventing balantidiasis in populations exposed to B. coli?

    <p>Improvement of sanitary conditions and hygiene (C)</p> Signup and view all the answers

    What is the primary habitat of Balantidium coli?

    <p>Large intestine of humans, pigs, and monkeys (D)</p> Signup and view all the answers

    What is characteristic of the trophozoite stage of Balantidium coli?

    <p>It is a large ovoid cell measuring 60–70 μm in length. (C)</p> Signup and view all the answers

    Which structure is absent in the cyst of Balantidium coli?

    <p>Cilia (D)</p> Signup and view all the answers

    What type of transmission is primarily associated with Balantidiasis?

    <p>Ingestion of cysts in contaminated food and water (B)</p> Signup and view all the answers

    What triggers the excystation process in Balantidium coli's life cycle?

    <p>Ingestion of the cyst (C)</p> Signup and view all the answers

    Which of the following describes the role of pigs in the life cycle of Balantidium coli?

    <p>They are the only natural host. (D)</p> Signup and view all the answers

    During which phase of the life cycle do trophozoites multiply by transverse binary fission?

    <p>After ingestion of cysts (D)</p> Signup and view all the answers

    What is the significance of the anal pore (cytopyge) in the trophozoite of Balantidium coli?

    <p>It allows for the expulsion of waste. (B)</p> Signup and view all the answers

    Trophozoites of B. coli do not cause inflammatory reactions when they burrow into the intestinal mucosa.

    <p>False (B)</p> Signup and view all the answers

    Balantidiasis can lead to intestinal perforation and even death in severe cases.

    <p>True (A)</p> Signup and view all the answers

    Tetracycline is used for the treatment of B. coli infections at a dosage of 250 mg three times daily.

    <p>False (B)</p> Signup and view all the answers

    B. coli can invade extraintestinal sites similar to E. histolytica.

    <p>False (B)</p> Signup and view all the answers

    Chronic balantidiasis is characterized by diarrhea alternating with constipation.

    <p>True (A)</p> Signup and view all the answers

    The trophozoite of Balantidium coli is known to be freely motile and has a broad posterior end.

    <p>True (A)</p> Signup and view all the answers

    Balantidium coli is primarily transmitted through airborne particles.

    <p>False (B)</p> Signup and view all the answers

    The cyst of Balantidium coli typically measures between 60–80 μm in diameter.

    <p>False (B)</p> Signup and view all the answers

    In the life cycle of Balantidium coli, the sexual union by conjugation occurs frequently among trophozoites.

    <p>False (B)</p> Signup and view all the answers

    The macronucleus of the trophozoite in Balantidium coli is kidney-shaped.

    <p>True (A)</p> Signup and view all the answers

    Encystation in Balantidium coli occurs as the trophozoite passes through the small intestine.

    <p>False (B)</p> Signup and view all the answers

    Humans are considered the natural hosts for Balantidium coli.

    <p>False (B)</p> Signup and view all the answers

    The cilia surrounding the mouth of the trophozoite are smaller than the rest on its surface.

    <p>False (B)</p> Signup and view all the answers

    What are the possible consequences of untreated balantidiasis?

    <p>Untreated balantidiasis can lead to intestinal perforation, peritonitis, and even death.</p> Signup and view all the answers

    How does the presence of concurrent infections influence the pathogenesis of Balantidium coli?

    <p>Concurrent infections can further lower the host's resistance, facilitating the establishment of B. coli and increasing the risk of clinical disease.</p> Signup and view all the answers

    Why is stool examination particularly important in diagnosing balantidiasis?

    <p>Stool examination is critical because it allows for the direct visualization of trophozoites and cysts, confirming the presence of B. coli.</p> Signup and view all the answers

    What precautions should be taken to prevent the transmission of Balantidium coli?

    <p>Precautions include avoiding contamination of food and water with feces and preventing human-pig contact.</p> Signup and view all the answers

    In terms of treatment options, what are the alternatives to tetracycline for Balantidium coli infections?

    <p>Alternatives to tetracycline include doxycycline, metronidazole, and nitroimidazole.</p> Signup and view all the answers

    What is the main function of the anal pore (cytopyge) in the trophozoite of Balantidium coli?

    <p>The anal pore (cytopyge) is responsible for the excretion of waste materials from the trophozoite.</p> Signup and view all the answers

    What key structures are present in the cyst stage of Balantidium coli?

    <p>The cyst contains a thick double-layered wall, a macronucleus, a micronucleus, and food vacuoles.</p> Signup and view all the answers

    Describe the differences in structure between the trophozoite and cyst stages of Balantidium coli.

    <p>The trophozoite is large, motile, and has cilia, while the cyst is spherical, non-motile, and surrounded by a thick wall.</p> Signup and view all the answers

    How is the transmission of Balantidium coli primarily facilitated in humans?

    <p>Transmission occurs through the ingestion of food and water contaminated with cysts from feces.</p> Signup and view all the answers

    What role do pigs play in the life cycle of Balantidium coli?

    <p>Pigs serve as the natural reservoir and source of cysts that can infect humans and other accidental hosts.</p> Signup and view all the answers

    What occurs during the process of encystation in Balantidium coli?

    <p>Encystation involves the trophozoite rounding up and secreting a tough cyst wall as it moves through the colon.</p> Signup and view all the answers

    What triggers the process of excystation in Balantidium coli?

    <p>Excystation is triggered upon the ingestion of cysts, which then occur in the small intestine.</p> Signup and view all the answers

    Explain the significance of the contractile vacuoles found in the cytoplasm of the trophozoite.

    <p>Contractile vacuoles help regulate osmotic pressure and remove excess water from the trophozoite.</p> Signup and view all the answers

    Clinical disease occurs when the resistance of the host is lowered by predisposing factors like malnourishment, alcoholism, and __________.

    <p>concurrent infection</p> Signup and view all the answers

    In symptomatic disease caused by balantidiasis, patients may experience diarrhea or frank dysentery accompanied by __________.

    <p>abdominal colic</p> Signup and view all the answers

    The drug of choice for treating B. coli infections is __________, administered for 10 days.

    <p>tetracycline</p> Signup and view all the answers

    To prevent balantidiasis, avoidance of contamination of food and water with human or animal __________ is necessary.

    <p>feces</p> Signup and view all the answers

    In chronic balantidiasis, patients may experience diarrhea that alternates with __________.

    <p>constipation</p> Signup and view all the answers

    Balantidium coli primarily resides in the large intestine of man, pigs, and ______.

    <p>monkeys</p> Signup and view all the answers

    The trophozoite of Balantidium coli is actively motile due to the presence of short delicate ______ over its entire surface.

    <p>cilia</p> Signup and view all the answers

    The cyst stage of Balantidium coli is spherical in shape and measures approximately ______ μm in diameter.

    <p>40–60</p> Signup and view all the answers

    Humans can become infected with Balantidium coli through the ingestion of contaminated food and water that contain ______.

    <p>cysts</p> Signup and view all the answers

    Once the cyst is ingested, excystation occurs in the small intestine, leading to the release of a single ______.

    <p>trophozoite</p> Signup and view all the answers

    The life cycle of Balantidium coli is classified as ______ because it occurs in one host only.

    <p>monoxenous</p> Signup and view all the answers

    During the life cycle, encystation occurs as the trophozoite passes down the ______ or in evacuated stool.

    <p>colon</p> Signup and view all the answers

    Balantidiasis is predominantly considered a ______ infection due to its transmission from animals to humans.

    <p>zoonotic</p> Signup and view all the answers

    Match the clinical features with their corresponding descriptions for balantidiasis:

    <p>Diarrhea = Frequent loose stools associated with inflammatory reaction Tenesmus = A feeling of incomplete bowel evacuation Vomiting = Expulsion of stomach contents, often accompanying nausea Abdominal colic = Severe cramping pain in the abdomen</p> Signup and view all the answers

    Match the treatment options with their respective details for B. coli infections:

    <p>Tetracycline = 500 mg, 4 times daily for 10 days Doxycycline = Effective alternative to tetracycline Metronidazole = Reported to be useful in some cases Nitroimidazole = Often considered in treatment as a secondary option</p> Signup and view all the answers

    Match the terms related to the lifecycle of Balantidium coli with their proper definitions:

    <p>Trophozoite = The motile, feeding stage of the parasite Cyst = The resistant stage capable of surviving outside the host Encystation = The process of forming a cyst from a trophozoite Excystation = The release of trophozoites from cysts upon entering the intestine</p> Signup and view all the answers

    Match the methods of laboratory diagnosis with their corresponding descriptions:

    <p>Stool Examination = Observation of trophozoites and cysts in feces Biopsy = Used when stool tests are negative for B. coli Culture = Growing the parasite in vitro for identification Stool Concentration = Enhances detection of cysts in formed stools</p> Signup and view all the answers

    Match the prevention strategies with their appropriate actions against balantidiasis:

    <p>Avoidance of contamination = Preventing fecal contamination of food and water Treatment of infected individuals = Targeting persons shedding B. coli cysts Prevention of human-pig contact = Minimizing exposure to animal reservoirs Hygiene practices = Encouragement of sanitary habits to reduce transmission</p> Signup and view all the answers

    Match the following stages of Balantidium coli with their descriptions:

    <p>Trophozoite = Motile, invasive stage found in dysenteric stool Cyst = Spherical, infective stage surrounded by a thick wall Excystation = Process where cysts transform into trophozoites Encystation = Formation of cysts from trophozoites</p> Signup and view all the answers

    Match the following components of the Balantidium coli life cycle with their roles:

    <p>Macronucleus = Large kidney-shaped nucleus in trophozoite Micronucleus = Smaller nucleus located within the macronucleus Contractile vacuoles = Structures that help regulate water balance Adoral cilia = Larger cilia around the mouth opening</p> Signup and view all the answers

    Match the following transmission modes with their descriptions:

    <p>Zoonosis = Transmission occurs from animals to humans Fecal-oral route = Infection through contaminated food or water Direct contact = Transmission via contact with infected carriers Airborne particles = Infection through inhalation of contaminated particles</p> Signup and view all the answers

    Match the following characteristics of the habitat with their corresponding hosts:

    <p>Natural host = Pig Accidental host = Man Reservoir = Monkey Alternative reservoir = Rat</p> Signup and view all the answers

    Match the following symptoms with their respective descriptions in balantidiasis:

    <p>Diarrhea = Frequent watery stools Dysentery = Stools containing blood and mucus Constipation = Intermittent periods of infrequent stools Abdominal pain = Discomfort and cramping in the abdominal area</p> Signup and view all the answers

    Match the following components associated with the cyst of Balantidium coli:

    <p>Thick wall = Protective layer surrounding the cyst Granular cytoplasm = Cytoplasm with a grainy appearance Viability duration = Cysts remain viable for 1 to 2 days in feces Infective stage = Cyst is the infective form of B. coli</p> Signup and view all the answers

    Match the following descriptions with the corresponding features of the trophozoite:

    <p>Pellicle = Delicate covering with longitudinal striations Peristome = Groove leading to the mouth Cytostome = Opening for food intake Cytopyge = Anal pore for waste elimination</p> Signup and view all the answers

    Match the following life cycle processes of Balantidium coli with their corresponding sequence:

    <p>Ingestion of cysts = Entry point of the infective form Excystation = Transformation in the small intestine Migration to large intestine = Site for trophozoite multiplication Encystation = Formation of cysts from trophozoites before exit</p> Signup and view all the answers

    Study Notes

    Balantidium coli

    • Resides in the large intestine of humans, pigs, and monkeys.
    • Trophozoite is the active, invasive stage found in dysenteric stool.
      • Large, ovoid cell measuring 60-70 µm in length and 40-50 µm in breadth.
      • Enclosed in a delicate pellicle with longitudinal striations.
      • Motility is driven by short, delicate cilia covering the entire surface.
      • Anterior end is narrow, posterior end is broad.
      • Peristome (groove) leading to the mouth (cytostome) and a short, funnel-shaped gullet (cytopharynx) at the anterior end.
      • Small anal pore (cytopyge) at the posterior end.
      • Larger cilia (adoral cilia) surround the mouth.
      • Two nuclei: a large, kidney-shaped macronucleus and a smaller micronucleus located within its concavity.
      • Cytoplasm contains one or two contractile vacuoles and several food vacuoles.
    • Cyst is the spherical infective stage measuring 40-60 µm in diameter.
      • Surrounded by a thick, transparent double-layered wall.
      • Granular cytoplasm containing macronucleus, micronucleus, and vacuoles.
      • Found in chronic cases and carriers.

    Transmission

    • Zoonosis: Humans acquire infection by ingesting food and water contaminated with feces containing B. coli cysts.
    • Infection acquired from pigs, other animal reservoirs, or human carriers.

    Life Cycle

    • Monoxenous: Completes its life cycle in a single host.
    • Natural host: Pig.
    • Accidental host: Human.
    • Reservoirs: Pig, monkey, and rat.
    • Infective form: Cyst.
    • Cyst ingested and undergoes excystation in the small intestine.
    • Single trophozoite is released from each cyst and migrates to the large intestine.
    • Trophozoites multiply by transverse binary fission in the large intestine.
    • Infrequent sexual union (conjugation) occurs with reciprocal exchange of nuclear material between two trophozoites enclosed within a single cyst wall.
    • Encystation occurs as the trophozoite passes down the colon or is evacuated in stool.
    • Cell rounds up and secretes a tough cyst wall around it.
    • Cysts remain viable in feces for one to two days and can contaminate food and water, transmitting the infection to humans or animals.

    Pathogenesis

    • Clinical disease only occurs when host resistance is lowered by predisposing factors such as malnutrition, alcoholism, achlorhydria, co-infection with Trichuris trichiura, or bacterial infections.
    • Trophozoites burrow into the intestinal mucosa, form colonies, and initiate inflammatory reactions.
    • Leads to mucosal ulcers and submucosal abscesses resembling lesions in amoebiasis.
    • B. coli does not invade the liver or other extraintestinal sites, unlike Entamoeba histolytica.

    Clinical Features

    • Balantidiasis (symptomatic disease) resembles amoebiasis, causing diarrhea or dysentery with abdominal colic, tenesmus, nausea, and vomiting.
    • Balantidium ulcers may be secondarily infected by bacteria.
    • Intestinal perforation, peritonitis, and even death may occur in rare cases.
    • Involvement of genital and urinary tracts is uncommon.
    • Chronic balantidiasis presents with alternating diarrhea and constipation.

    Laboratory Diagnosis

    • Stool Examination: Demonstration of trophozoites and cysts in feces (trophozoites in diarrheic feces, cysts in formed stools).
    • Biopsy: When stool examination is negative.
    • Culture: B. coli can be cultured in vitro using Locke’s egg albumin medium or NIH polyxenic medium, similar to Entamoeba histolytica.

    Treatment

    • Tetracycline: Drug of choice, 500 mg four times daily for ten days.
    • Doxycycline: Alternative treatment.
    • Metronidazole and Nitroimidazoles: Reported to be effective in some cases.

    Prophylaxis

    • Avoid contamination of food and water with human or animal feces.
    • Prevent human-pig contact.
    • Treat infected pigs.
    • Treat individuals shedding B. coli cysts.

    Balantidium coli

    • Habitat: Large intestine of humans, pigs, and monkeys.
    • Trophozoite:
      • Actively motile, invasive stage found in dysenteric stool.
      • Large ovoid cell, about 60–70 μm long and 40–50 μm wide.
      • Covered in cilia for motility.
      • Anterior end is narrow, posterior end is broad.
      • Has a groove leading to the mouth (cytostome) and a short, funnel-shaped gullet (cytopharynx).
      • Contains a large kidney-shaped macronucleus and a small micronucleus.
      • Contains 1 to 2 contractile vacuoles and several food vacuoles.
    • Cyst:
      • Spherical, 40–60 μm in diameter.
      • Surrounded by a thick, transparent double-layered wall.
      • Contains macronucleus, micronucleus, and vacuoles.
      • Infective stage, found in chronic cases and carriers.
    • Mode of Transmission:
      • Zoonosis, acquired through ingestion of food and water contaminated with feces containing cysts.
      • Transmission from pigs, other animal reservoirs, or human carriers.
    • Life Cycle:
      • Monoxenous (one host).
      • Natural host: Pig.
      • Accidental host: Human.
      • Reservoirs: Pig, monkey, and rat.
      • Infective form: Cyst.
      • Cyst ingestion leads to excystation in the small intestine, releasing a trophozoite.
      • Trophozoite migrates to the large intestine and multiplies by transverse binary fission.
      • Infrequent conjugation (sexual union) may occur, with reciprocal exchange of nuclear material.
      • Encystation occurs during passage through the colon or in evacuated stool.
      • Cysts remain viable for 1-2 days and can contaminate food and water, allowing transmission to other humans and animals.
    • Pathogenesis:
      • Clinical disease occurs when host resistance is lowered by factors like malnourishment, alcoholism, achlorhydria, concurrent infections, or bacterial infections.
      • Trophozoites invade the intestinal mucosa, forming colonies and initiating inflammation.
      • This leads to mucosal ulcers and submucosal abscesses, similar to amoebiasis.
      • Unlike E. histolytica, B. coli does not invade the liver or other extraintestinal sites.
    • Clinical Features:
      • Balantidiasis resembles amoebiasis, causing diarrhea or dysentery with abdominal colic, tenesmus, nausea, and vomiting.
      • Balantidium ulcers can be secondarily infected by bacteria.
      • Intestinal perforation, peritonitis, and death can occur in rare cases.
      • Genital and urinary tract involvement is uncommon.
      • Chronic balantidiasis features alternating diarrhea and constipation.
    • Laboratory Diagnosis:
      • Stool examination: Demonstration of trophozoites (diarrheic stool) and cysts (formed stool).
      • Biopsy: When stool examination is negative.
      • Culture: B. coli can be cultured in vitro in Locke's egg albumin medium or NIH polyxenic medium.
    • Treatment:
      • Tetracycline (500 mg, 4 times daily for 10 days) is the drug of choice.
      • Doxycycline is an alternative.
      • Metronidazole and nitroimidazoles have also been reported as effective in some cases.
    • Prophylaxis:
      • Avoid contamination of food and water with human or animal feces.
      • Prevent human-pig contact.
      • Treat infected pigs.
      • Treat individuals shedding B. coli cysts.

    Balantidium coli

    • Balantidium coli is a protozoan parasite that resides in the large intestine of humans, pigs and monkeys.
    • The trophozoite is the actively motile and invasive stage of the parasite, found in dysenteric stool.
    • It is a large cell (60-70 µm in length, 40-50 µm in breadth) enclosed in a delicate pellicle with longitudinal striations.
    • Motility is due to cilia covering the entire surface of the cell.
    • The anterior end is narrow, the posterior end broad.
    • The anterior end features a groove called the peristome, leading to the mouth (cytostome), and a short funnelshaped gullet (cytopharynx).
    • The posterior end houses a small anal pore (cytopyge).
    • The cilia situated around the mouth are larger and are referred to as adorai cilia.
    • The cell is characterized by two nuclei: a large kidney-shaped macronucleus and a small micronucleus positioned within its concavity.
    • The cytoplasm contains one or two contractile vacuoles and several food vacuoles.

    Cyst

    • The cyst is spherical (40-60 µm in diameter).
    • It has a thick, transparent, double-layered wall.
    • The cyst is the infective stage of B. coli and is found in chronic cases and carriers.

    Mode of Transmission

    • Balantidiasis is a zoonotic infection.
    • Humans acquire infection through ingestion of contaminated food and water containing cysts.
    • Infection can be acquired from pigs and other animal reservoirs or from human carriers.

    Life Cycle

    • B. coli completes its life cycle in a single host (monoxenous).
    • Natural host: Pig.
    • Accidental host: Man.
    • Reservoirs: Pig, monkey, and rat.
    • Infective form: Cyst.
    • After ingestion, excystation occurs in the small intestine, releasing a single trophozoite.
    • The trophozoite then migrates to the large intestine.
    • Liberated trophozoites multiply in the large intestine by transverse binary fission.
    • Sexual union (conjugation) occurs infrequently, with reciprocal exchange of nuclear material between two trophozoites within a single cyst wall.
    • Encystation occurs as the trophozoite traverses the colon or is evacuated in the stool.
    • The cell rounds up, secreting a tough cyst wall around it.
    • Cysts remain viable in feces for one to two days and can contaminate food and water, leading to transmission to other humans or animals.

    Pathogenesis

    • Clinical disease develops when the host's resistance is lowered by predisposing factors such as malnourishment, alcoholism, achlorhydria, concurrent infection with Trichuris trichiura, or bacterial infection.
    • Trophozoites burrow into the intestinal mucosa, forming colonies and triggering inflammatory reactions.
    • This leads to mucosal ulcers and submucosal abscesses, resembling the lesions seen in amoebiasis.
    • Unlike Entamoeba histolytica, B. coli does not invade the liver or other extraintestinal sites.

    Clinical Features

    • Symptomatic disease or balantidiasis resembles amoebiasis, characterized by diarrhea or dysentery, abdominal colic, tenesmus, nausea, and vomiting.
    • Balantidium ulcers may be secondarily infected by bacteria.
    • Intestinal perforation, peritonitis, and even death can occur, although these complications are relatively rare.
    • Involvement of the genital and urinary tracts may occur, though this is uncommon.
    • In chronic balantidiasis, patients experience diarrhea alternating with constipation.

    Laboratory Diagnosis

    • Stool examination: Demonstration of trophozoites and cysts in feces (trophozoites in diarrheic feces, cysts in formed stools).
    • Biopsy: When stool examination is negative.
    • Culture: Similar to Entamoeba histolytica, B. coli can be cultured in vitro in Locke's egg albumin medium or NIH polyxenic medium.

    Treatment

    • Tetracycline is the drug of choice, administered at 500 mg four times daily for 10 days.
    • Alternatively, Doxycycline can be used.
    • Metronidazole and nitroimidazoles have also been found to be helpful in some cases.

    Prophylaxis

    • Avoid contamination of food and water with human or animal feces.
    • Prevent human-pig contact.
    • Treat infected pigs.
    • Treat individuals shedding B. coli cysts.

    Balantidium coli

    • Habitat: Large intestine of humans, pigs, and monkeys.
    • Trophozoite: Actively motile and invasive stage found in dysenteric stool.
      • Large ovoid cell (60–70 μm length, 40–50 μm breadth).
      • Enclosed in a delicate pellicle with longitudinal striations.
      • Moves using cilia on its surface.
      • Anterior end is narrow, posterior end is broad.
      • Peristome: Groove leading to the mouth (cytostome).
      • Cytopharynx: Short funnel-shaped gullet.
      • Cytopyge: Small anal pore.
      • Adoral cilia: Larger cilia around the mouth.
      • Nuclei: One large kidney-shaped macronucleus and one small micronucleus.
      • Cytoplasm: Contains one or two contractile vacuoles and several food vacuoles.
    • Cyst: Spherical shape, 40–60 μm in diameter.
      • Surrounded by a thick double-layered wall.
      • Contains a granular cytoplasm, macronucleus, micronucleus, and vacuoles.
      • Infective stage of B.coli.
      • Found in chronic cases and carriers.

    Transmission and Life Cycle

    • Zoonosis: Humans acquire infection through ingestion of food and water contaminated with feces containing cysts.
    • Reservoirs: Pigs, monkeys, and rats.
    • Infective Form: Cyst.
    • Monoxenous: The parasite completes its life cycle in a single host.
      • Natural host: Pig.
      • Accidental host: Human.
    • Life Cycle:
      • Cyst ingestion leads to excystation in the small intestine.
      • One trophozoite emerges from each cyst and migrates to the large intestine.
      • Trophozoites multiply in the large intestine by transverse binary fission.
      • Conjugation: Sexual union occurs infrequently where two trophozoites exchange nuclear material within a single cyst wall.
      • Encystation: Occurs as the trophozoite moves through the colon or in evacuated stool.
      • Cell rounds up and secretes a tough cyst wall.
      • Cysts can remain viable in feces for 1-2 days, contaminating food and water, and transmitting the infection.

    Pathogenesis

    • Clinical disease: Occurs when host resistance is lowered (malnourishment, alcoholism, achlorhydria, concurrent infections).
    • Trophozoites: Burrow into the intestinal mucosa, form colonies, and cause inflammatory response.
    • Ulcers and abscesses: Resulting lesions resemble those in amoebiasis.
    • Extraintestinal Invasion: Unlike E. histolytica, B.coli does not invade the liver or other organs.

    Clinical Features

    • Balantidiasis: Resembles amoebiasis.
    • Symptoms: Diarrhea or dysentery, abdominal colic, tenesmus, nausea, vomiting.
    • Bacterial Infections: Balantidium ulcers can be secondarily infected by bacteria.
    • Complications: Intestinal perforation, peritonitis, death.
    • Genital and Urinary Tracts: Involvement is rare.
    • Chronic Balantidiasis: Diarrhea alternating with constipation.

    Laboratory Diagnosis

    • Stool Examination: Demonstration of trophozoites and cysts in feces (trophozoites in diarrheic feces, cysts in formed stools ).
    • Biopsy: When stool examination is negative.
    • Culture: B.coli can be cultured in vitro using media similar to that for Entamoeba histolytica.

    Treatment

    • Drug of Choice: Tetracycline (500 mg, 4 times daily for 10 days).
    • Alternatives: Doxycycline, metronidazole, nitroimidazoles.

    Prophylaxis

    • Prevention of Contamination: Avoid contamination of food and water with human or animal feces.
    • Human-Pig Contact: Prevent human-pig contact.
    • Treatment of Infected Pigs and Carriers: Treat infected pigs and individuals shedding B.coli cysts.

    Balantidium Coli

    • Habitat: Large intestine of humans, pigs, and monkeys.
    • Trophozoite:
      • Actively motile, invasive stage of the parasite.
      • Found in dysenteric stool.
      • Large ovoid cell (60–70 μm long, 40–50 μm wide).
      • Encased in a delicate pellicle with longitudinal striations.
      • Motility due to short, delicate cilia covering the cell surface.
      • Narrow anterior end, broad posterior end.
      • Anterior End:
        • Peristome: Groove leading to the mouth (cytostome).
        • Cytopharynx: Short, funnel-shaped gullet.
      • Posterior End: Small anal pore (cytopyge).
      • Cilia: Larger around the mouth (adoral cilia).
      • Nuclei:
        • Large, kidney-shaped macronucleus.
        • Small micronucleus within the macronucleus' concavity.
      • Cytoplasm:
        • 1-2 contractile vacuoles.
        • Multiple food vacuoles.
    • Cyst:
      • Spherical shape (40–60 μm in diameter).
      • Thick, transparent, double-layered wall.
      • Granular cytoplasm.
      • Contains macronucleus, micronucleus, and vacuoles.
      • Infective stage of B. coli, found in chronic cases and carriers.
    • Transmission:
      • Zoonosis (transmitted from animals to humans).
      • Humans acquire infection by ingesting food and water contaminated with feces containing B. coli cysts.
      • Infection sources include pigs, other animal reservoirs, or human carriers.
    • Life Cycle:
      • Monoxenous (passes its life cycle in one host).
        • Natural host: Pig.
        • Accidental host: Human.
        • Reservoirs: Pigs, monkeys, and rats.
      • Infective form: Cyst.
      • Cyst Ingestion:
        • Excystation occurs in the small intestine releasing a single trophozoite.
      • Trophozoite Migration:
        • Trophozoite migrates to the large intestine.
      • Multiplication:
        • Trophozoites multiply in the large intestine via transverse binary fission.
      • Conjugation:
        • Infrequent sexual union with reciprocal exchange of nuclear material between two trophozoites enclosed within a single cyst wall.
      • Encystation:
        • Occurs as the trophozoite passes down the colon or in evacuated stool.
        • Trophozoite rounds up and secretes a tough cyst wall.
        • Cysts remain viable in feces for 1-2 days, contaminating food and water, and transmitting to other humans or animals.
    • Pathogenesis:
      • Clinical disease occurs when host resistance is lowered by factors like:
        • Malnourishment.
        • Alcoholism.
        • Achlorhydria.
        • Concurrent infection with Trichuris trichiura.
        • Bacterial infections.
      • Trophozoites burrow into the intestinal mucosa, establishing colonies and triggering an inflammatory reaction.
      • This leads to mucosal ulcers and submucosal abscesses, similar to lesions seen in amoebiasis.
      • Unlike E. histolytica, B. coli doesn't invade the liver or other extraintestinal sites.
    • Clinical Features:
      • Symptomatic disease (balantidiasis) resembles amoebiasis.
      • Causes diarrhea or dysentery with:
        • Abdominal colic.
        • Tenesmus.
        • Nausea.
        • Vomiting.
      • Balantidium ulcers may be secondarily infected by bacteria.
      • Occasionally, intestinal perforation, peritonitis, and even death can occur.
      • In rare cases, the genital and urinary tracts may be involved.
      • Chronic balantidiasis presents with alternating diarrhea and constipation.
    • Laboratory Diagnosis:
      • Stool Examination:
        • Demonstration of trophozoites and cysts in feces.
          • Trophozoites found in diarrheic feces.
          • Cysts found in formed stools.
      • Biopsy: When stool examination is negative.
      • Culture:
        • Similar to Entamoeba histolytica, B. coli can be cultured in vitro using Locke's egg albumin medium or NIH polyxenic medium.
    • Treatment:
      • Drug of Choice: Tetracycline (500 mg, 4 times daily for 10 days).
      • Alternative: Doxycycline.
      • Other Effective Treatments: Metronidazole and nitroimidazole.
    • Prophylaxis:
      • Avoid contamination of food and water with human or animal feces.
      • Prevent human-pig contact.
      • Treat infected pigs.
      • Treat individuals shedding B. coli cysts.

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    Balantidium Coli PDF

    Description

    Explore the fascinating organism Balantidium coli, which resides in the intestines of humans and various animals. This quiz covers its structure, life cycle, and distinguishing characteristics, including motility, nuclei, and reproductive stages. Ideal for students of microbiology or parasitology.

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