This document summarizes information about Balantidium coli, the largest protozoan parasite that infects humans. It is classified within the kingdom Protista, phylum Ciliophora. B. coli has two life stages, a trophozoite stage that is motile and pear-shaped, containing two nuclei and contractile vacuoles, and a cyst stage that forms under conditions like constipation. B. coli typically infects pigs and is transmitted to humans via ingestion of cysts. In humans, it can cause diarrhea and dysentery through ulceration in the large intestine. Diagnosis involves finding cysts in feces and treatment involves antibiotics like tetracycline or metronidazole.
4. MORPHOLOGY
2 stages - Trophozoite & Cyst
Trophozoites – ovoid, egg – shaped, pear – shaped;
occasionally subcylindrical
Body surface – covered with cilia
Cytostome – permanent mouth
Cytopyge - excretory organelle
Trophozoite – 2 nuclei
Occasionally, vegetative forms are seen without
macronucleus
2 contractile vacuoles – one terminal; other near centre
Food vacuoles – many; containing starch grains, cell
fragments, bacteria, erythrocytes
Organism – actively motile and moves quickly when
examined under microscope
5. Contd..
Under conditions like constipation & bowel
dehydration – organisms undergo encystment
inside the host
May also undergo encystment outside
Cysts are ovoid to spherical
Light yellowish or greenish with hyaline cytoplasm
Cyst wall has 2 membranes
Reproduction – by transverse
binary fission (homothetogenic)
conjugation may also take
place
6. LIFECYCLE
• Transmission is by cyst
• Commonly seen in lumen of
large intestine of pigs
• Pig is the usual source of
infection for man
7. PATHOGENESIS
Opportunistic commensals
Act as secondary invaders
Produce hyaluronidase – enlarges already existing lesions
May cause superficial to deep ulcerations – associated with
mild enteritis
In man: pathogenic; diarrhoea and dysentery; produces
similar lesions to Entamoeba histolytica
Ulcers – coagulative necrosis and haemorrhages
8.
9. DIAGNOSIS AND
TREATMENT
Detection of cyst in faeces or histological examination
Clinical signs and post mortem – ulcerative condition of large
intestine and large numbers of Balantidium coli
Treatment not necessary in pigs
If acute, treated with tetracycline antibiotics
Carbarsone, diiodohydroxyquinine, tetracyclines, paramycin,
metronidazole and imidazole can be used for human
balantidiosis
10. PREVENTION
Purification of drinking water
Proper handling of food
Careful disposal of human feces and
pig faeces
Monitoring the contacts of
balantidiasis patients