Parasitology Flashcards
What is obligate parasite
completely dependent on the host during a segment or all of its life cycle, e.g. Plasmodium spp.
What is facultative parasite
exhibits both parasitic and non-parasitic modes of living; hence does not absolutely depend on the parasitic way of life, but is capable of adapting to it if placed on a host. e.g. Naegleria fowleri
What is accidental parasite
when a parasite attacks an unnatural host and survives. e.g. Hymenolepis diminuta (rat tapeworm).
What is erratic parasite
is one that wanders in to an organ in which it is not usually found. e.g. Entamoeba histolytica in the liver or lung of humans.
What is a zoonotic parasite
Zoonotic parasite- primarily infects animals and is transmittable to humans, e.g. Fasciola species
What is Permanent parasite
lives in or on its host without leaving it e.g. lice.
What is opportunistic parasite
Causes illness when the immune system of organism is impaired. HIVAiIds can cause impairment
E.g. Toxoplasma gondii
What is a paratenic host
Host that serves as temporary refuge and vehicle for reaching bad obligate host eg plasmodium in mosquito
What may produce a negative host response and what are he responses
physical presence of a parasite and its metabolic waste products can stimulate a negative host response, eg production of alkaline phosphatase, corticosteroids, etc.
What are the two stages of amoeba
- Trophozoite – actively motile feeding stage.
* Cyst – quiescent, resistant, infective stage.
True/false
Parasites in the ‘wrong host’ are in general more pathogenic
True
What are the four classes of protozoans
Sporozoans(Plasmodium)
Ciliophora( Ciliates)
Mastigophora( Flagellates )
Sardonica (Amoeba)
Pathogenesis if amoeba read
Pathogenesis
•Trophozoites divide and produce extensive local necrosis in the large intestine.
•Invasion into the deeper mucosa with extension into the peritoneal cavity may occur.
•This can lead to secondary involvement of other organs, primarily the liver but also the lungs, brain, and heart.
•Extraintestinal amebiasis is associated with trophozoites.
•Amoebasmultiply rapidly in an anaerobic environment, because the trophozites are killed by ambient oxygen concentration.
What is the treatment of amoeba infection in cyst and trophozytes
Trophozoites: •metrondiazole, •tinidazole •chloroquine •Cysts: •iodoquinol, •diloxanide furoate, •paromomycin •The cysticidal agents are commonly recommended for asymptomatic carriers who handle food for public use
•it is a pear-shaped organism with a central nucleus and four anterior flagella
Trychomona
