4. GENERAL CHARACTERS:
1. Minute, microscopic animals, but a few are
visible to the naked eye.
2. Body is unicellular or acellular containing one
or more nucleus.
3. The protoplasm is differentiated into organelles.
They have acellular or protoplasmic level of
organization.
4. Locomotion is effected by finger-like
pseudopodia, whip-like flagella or hair-like cilia.
5. Locomotor organelles are absent in some forms.
PROTOZOA
5. 6. Nutrition may be holozoic, holophytic,
saprophytic, mixotrophic or parasitic.
7. Digestion is intracellular and occurs
inside food vacuoles.
8. Respiration and excretion occurs
through general body surface.
9. Freshwater forms have contractile
vacuoles for osmoregulation.
GENERAL CHARACTERS:
PROTOZOA
6. 10. Reproduction asexual and sexual.
• Asexual reproduction is by:
• binary fission.
• multiple fission.
• budding.
• Sexual reproduction occurs by:
• Conjugation.
• Syngamy (fusion of gametes).
11. Encystment occurs in freshwater and many
parasitic forms. It helps in dispersal and to
resist unfavourable conditions.
E.g. Amoeba, Entamoeba, Euglena and Paramecium.
GENERAL CHARACTERS:
PROTOZOA
7. The association between two different
species may be called SYMBIOSIS
Three types of symbiotic relationships
SYMBIOSIS: two types of organisms living
together.
an association in which both are so
dependent upon other, that is
benefit to both organisms.
Good example are the flagellated protozoans in gut of termite.
8. from the Latin for “eating at the
same table” an association in
which the parasite is deriving
benefit without causing injury to
its host.
Good example might be Entamoeba gingivlis in the human
mouth.
is a relationship in which the
parasite is deriving benefit and
causing injury to its host.
Example: Entamoeba histolytica & Humans.
9. PARASITE: An organism which
derives benefit at the expense of its
host. (Ascaris & Humans)
HOST: That organism which is
necessary for the development of a
parasite. (Snail & Schistosoma)
HYPERPARASITE:
An organism which serving as a host
for another parasitic species.
(Plasmodium in female Anopheles Mosquito)
Describing of the some Terms of Parasitology:
10. TYPES OF PARASITES:
ENDOPARASITE: lives within its host.
e.g., (Ascaris in Humans)
ECTOPARASITE: lives on the surface of its host.
e.g., (Mosquitoes & Humans)
TEMPORARY PARASITE: is a free-living, but seeks
its host from time to time for food. (Mosquitoes & Humans)
PERMANENT PARASITE: remains all or most of its
life in or on its host. e.g., (Ascaris in Humans)
OBLIGATE PARASITE: stage necessary for
completion of life cycle. e.g., Entamoeba histolytica.
FACULTATIVE PARASITE : Normally free-living,
but can exist as a parasite, e.g., Strongyloides
stercoralis.
ACCIDENTAL PARASITE: A parasite found in an
abnormal host, e.g., Fasciola gigantica.
Terms Describing Parasites
11. TYPES OF HOSTS:
DEFINITIVE HOST: host in which the parasite
reaches sexual maturity and undergoes
reproduction. , e.g., Humans for Schistosomes.
INTERMEDIATE HOST: A host in which the
parasite undergoes larval development but does
not reach sexual maturity. , e.g., Bulinus snails
for Schistosoma haematobium.
RESERVOIR HOST: a host that makes the
parasite available for the transmission to
another host and is usually not affected by the
infection. e.g., Rodents & Leishmania.
VECTOR: Any agent, e.g. an arthropod, that
transmits a disease organism.
Terms Describing Hosts
14. The effect of the parasite on the host:
Nutritional effect.
Mechanical effect.
Toxic effect (toxins secreted).
Secondary infection.
The effect depends on several factors:
1. Number of parasite.
2. Size of parasite.
3. Shape of parasite.
4. Activity of parasite.
5. Site of infection (habitat).
15. Diagnosis of Parasitic Infections:
1. Clinical diagnosis.
2. Laboratory diagnosis.
Treatment of Parasitic Infections:
1. Medical and surgical treatment.
2. Chemotherapy.
3. Adequate nutrition.
Prevention and Control:
1. Reduction in sources.
2. Health education.
3. Control of reservoir hosts and vector.
16. Carolus Linnaeus (1707-1778)
• Binomial nomenclature
(Both names in Latin)
Suggested a system of classification that could be used
all over the world
• Had been confusion since some organisms had different names in different countries
• Every organism has its own
name
Ex. Homo sapiens
Classification of Parasites
Carolus Linnaeus began taxonomy in the 18th century
18. How to write the name of a parasite?
• The name of the parasite is written including the
genus and the species. (e.g Plasmodium
falciparum).
• The first letter in the genus name is written as
capital while the first letter in the species name is
written as small letter.
• (Plasmodium falciparum).
• Both names of the genus and the species are
either underlined or written in italic.
– Toxoplasma gondii = underlined.
or:
– Toxoplasma gondii = italic.
21. 21
Classification of protozoa
Sub
kingdom
Phylum Sub-phylum Genus-
examples
Species-
examples
Protozoa
Sarcomastig-
ophora
further divided into
Sarcodina
move by pseudopodia Entamoeba E. histolytica
Mastigophora
move by flagella
Giardia G. lamblia
Apicomplexa
no organelle of
locomotion
Plasmodium
P. falciparum,
P. vivax,
P. malariae,
P. ovale
Ciliophora
move by cillia
Balantidium B. coli
22. INTESTINAL PROTOZOANS
Transmission: direct fecal/oral
route.
Developmental stages:
–Trophozoite:
•motile, feeding stage.
•reproduces by binary fission.
–Cyst: -
•resistant stage, infective for humans.
