Characteristics of Protists
•mostly unicellular, some are multicellular
(algae)
•can be heterotrophic or autotrophic
most live in water (though some live in moist
soil or even the human body)
•ALL are eukaryotic (have a nucleus)
•A protist is any organism that is not a plant,
animal or fungus
Means- the very first
 Four
Phyla of Animallike Protists
Classified by how they move
1. Zooflagellates - flagella
2. Sarcodines - extensions of
cytoplasm (pseudopodia)
3. Ciliates - cilia
4. Sporozoans - do not move

Leishmania
 Protist:
Giardia
Transmission: Drinking
contaminated water (usually
outdoor streams and other
untreated water)
Symptoms: Severe diarrhea and
vomitting, the protist takes up
residence in the digestive tract.
Giardia lamblia
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Trichomonas vaginalis, an anaerobic,
parasitic flagellated protozoan
It is the causative agent of trichomoniasis,
and is the most common pathogenic
protozoan infection of humans in
industrialized countries.
The WHO has estimated that 180 million
cases of infection are acquired annually
worldwide. The estimates for North America
alone are between 5 and 8 million new
infections each year, with an estimated rate
of asymptomatic cases as high as 50%.
Treatment with antibiotics.
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Ameba
moves using pseudopodia ( "false feet" ), which
are like extensions of the cytoplasm --ameboid
movement
ingests food by surrounding and engulfing food
(endocytosis), creating a food vacuole
**reproducing by binary fission (mitosis)
**contractile vacuole - removes excess water
**Can cause amebic dysentery in humans diarrhea and stomach upset from drinking
contaminated water
**Other sarcodines: Foraminferans, Heliozoans
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Example- Paramecium
move using cilia
-has two nuclei: macronucleus, micronucleus
-food is gathered through the :mouth pore,
moved into a gullet, forms a food vacuole
-anal pore is used for removing waste
-contractile vacuole removes excess water
-exhibits avoidance behavior
-reproduces asexually (binary fission) or sexually
(conjugation)
-outer membrane -pellicle- is rigid and
-paramecia are always the same shape, like a
shoe
 Sporozoans
 do
not move on their own
parasitic
=Malaria is a sporozoan,
infects the liver and blood

Vector - an organism that can carry a
parasite, and is responsible for infecting
other organisms (host) with that parasite.
Vectors themselves are not harmful, but in
the battle against human disease, controlling
the vector can control the transmission of
parasites. The anopheles mosquito is the
vector for malaria.
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Protist: Plasmodium
Vector: Anopholes Mosquito
Statistics:
According to the World Health Organization,
300-500 million cases of malaria occur each year
Malaria results in 1.5-2.7 million deaths per year
(much more than AIDS)
Most cases occur in Africa and South America
Symptoms include fever, headache, vomiting and
other flu-like symptoms
The protist lives inside the bloodstream,
eventually clogging capillaries and destroying
blood cells, which will lead to death if not treated
Infected RBCs
1.
2.
Sporozoite- stage inside the
mosquito. Spores are injected
when the mosquito bites. The
spores then travel to the liver.
Merozoite- the Plasmodium
lives in the liver and multiplies.
It leaves the liver and enters the
blood.
3. Gametocyte- sexual
reproductive stage in the
mosquito only.
Trypanosoma
Questions for Thought
1. Does the United States have a
responsibility toward treating and
containing parasitic infections
found in other parts of the world?
2. Why is controlling the vector
important to control the disease?
3. One of the best ways to prevent
many parasitic infections is to have
a source of clean water. Why do you
think many third world countries
have more incidence of parasitic
infection that other countries?