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Ciliophora
They are group of protozoa characterized by head like structure called cilium which is important in A – movement B - nutrition .
This parasite have two species :-
Balantidium suis infect the pigs .
Balantidium coli infect the human .This disease is regarded as a zoonotic disease .Disease : BalantidiosisB.coli :- is the largest intestinal protozoa that effect human and can be seen macroscopically .
Morphology :- the parasite is observed in two stages only which are-: A – trophozoite-:
1 -Large size (40 µm to more than 70 µm). 2 -called the invasive stage.
3 -ovoidal in shape. 4 -covered by cilia & the anterior end are longer
than the posterior end.
5 -in the anterior end there is mouth called cytosome .
6 -the internal structures-: A- have two nuclei , the macronucleus
(the largest one) & micronucleus (the smallest
one ) . B- the macronucleus is kidney or bean in
shape . C- the micronucleus is small spherical
shape located in the concavity of
macronucleus . D- have two secretory contractile
vacuoles. E- numerous food vacuoles .
B- Cyst-:
1 -typically spherical in shape. 2 -surrounded by thick wall (one or two
layers ) by encystation in small intestine to protect the
parasite from the host.
3 -contain the macronucleus and contractile vacuoles are
visible in the cyst.
4 -the cilia are undetectable , only the roots may present.
Multiplication :- occur by two method 1 -Asexual type by binary fission.
2 -Sexual type by conjugation.
Life cycle :- direct life cycle or simple life cycle that mean the parasite not need for intermediate host. Mature cysts are passed with feces.
Transmission :- by ingestion of contaminated food or water (NOT in undercooked meat) with feces contain the
mature cyst. Excystation occurs in the small intestine, and the
trophozoites colonize in the large intestine . Trophozoites undergo encystation to produce infective cysts.
Cysts are the infective stage of this parasite .