ciliophora they are group of protozoa characterized by head like structure called cilium which is...

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 .