Terms Used in Relation to Ciliates

Cilia InfraciliatureContractile vacuoleCytostomeMacronucleusMicronucleusConjugationKinetosomeKinety

Pathogenic intestinal ciliate

Balantidium coli 大腸纖毛蟲

Geographical distribution

The only ciliate infects man

Sporadic infections in many place

Endemic area is New Guinea

Close association between man and pigs

Morphology

Trophozoite stage: reniform large macronucleus Smaller micronucleus in the concavity of macronucleus 30-300 μm in size, 2 contractile vacuoles Cytostome locate at anterior end as funnel-shape Locomotion with cilia, embedded in pellicle in longitudinal rows these rows (kineties) can be seen under phase contrast or interference contrast microscopy or by silver staining

Cystic stage: spherical or ovoid, 40-60 μm in diameter Thick and transparent cyst wall The cilia get absorbed Contractile, macro- and micro- nucleus, other structures are similar to trophozoites

Balantidium coli

Sliver stain

Balantidium coli

Trophozoite

Cyct

Balantidium coli

Trophozoite

Conjugation

Binary fission

Life cycle

Infection occurs from close association with pigs

Human to human transmission may also occur

Cyst is the infective stage of this parasite

Excystation occurs in small intestine

Multiple in large intestine by binary fission

Conjugation at the anterior end for a few minutes

Balantidium coli

Clinical Aspects

Balantidiasis: 大腸纖毛蟲症

Similar to amoebiasis in pathology and clinical symptoms

No extraintestinal pathogenesis

Trophozoites are often located in the submucosa of infected intestine

Balantidium coli

Diagnosis

Faeces examination Trophozoites or cysts

Actively motile trophoozites in acute dysentery( 痢疾 )

Easy to recognised by their characteristic macronucleus

Balantidium coli

Treatment

Drgus: Oxytetracycline: 30 mg/kg body weight/day in divided doses 6-hour for 10 days

Metronidazole: same as amoebiasis

Balantidium coli