Protozoa 1 Flashcards
an organism (parasite) that lives completely at the expense of another organism (host)
definition of parasite
a relationship between two organisms in which one (parasite) gets benefit (food, physical support) from the other (host). Parasite can have minor or major effects on the survival of its host.
definition of parasitism
antigen masking
antigen sharing
antigenic variation
intracellular location
strategies of parasites to avoid killing by host
what are the two families under parasite?
protozoa and metazoa (helminths)
sarcodina (amebas)
sporozoa (sporozoans)
mastigophora (flagellates)
ciliata (ciliates)
protozoa
entamoeba histolytica
- with pseudopodia
sarcodina (amebas)
toxoplasma
babesia
plasmodium
sarcocytis
cryptosporidium
- undergo sexual and asexual reproduction
- intracellular parasites
sporozoa (sporozoans)
giardia
trichomonas
trypanosoma
leishmania
mastigophora (flagellates)
balantidium coli
- a giant intestinal ciliate of humans and pigs
- the only human ciliated parasite
ciliata (ciliates)
what are the protozoans that are not in any of the 4 groups?
microsporidia
- opportunistic parasites of immunocompromised patients
blastocytis
- life cycle and infectious stage remain unknown
- polymorphic shape in stool or lab culture
flagellates, amebae, and ciliates multiply by…..
sporozoans reproduce by….
binary fission
schizogony (multiple fission)
sporozoans undergo sexual recombination which leads to…
genomic and antigenic variation
some parasitic protozoa able to evade host’s immune response because…
they are intracellular and/or undergo antigenic variation
latent and relapse infections occur with….
toxoplasma gondii (tissue cysts)
plasmodium vivax
plasmodium ovale (hypnozoites in liver)
infections by intracellular protozoa are difficult to treat because….
drugs must cross plasma membrane. no vaccines are available for any human parasitic disease