PROTOZOA
The protozoa are single-celled organisms which behave like
animals (ie. they do not make their own food through photosynthesis)
Pathogenic protozoa belong to four main groups :
Amoebae - “Blobs”
- no defined shape - move about
by extending parts of their
body (pseudopods)
- engulf food particles with
their bodies
eg. Entamoeba histolytica
(cause of amoebic dysentery), Acanthamoeba and Naegleria (infect
the brain to cause fatal encephalitis)
Flagellates - “Whipped” organisms
- rigid body shape with long
whiplike projections (flagella) which they beat to move
eg. Intestinal
- Giardia intestinalis
Blood - Trypanosomes
(causing sleeping sickness)
Venereal - Trichomonas vaginalis
Ciliates
- rigid body shape surrounded
by thousands of tiny beating hairs (cilia) which they use to
move about
eg. Balantidium
coli
Sporozoans - intracellular
parasites
- complex lifecycle with sexual
and asexual stages
eg. Malaria
(blood), Cryptosporidium (intestinal), Toxoplasma (can cause birth
deformities)
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© 2004 Dr Peter Darben