Are parasites eukaryotes, prokaryotes, or both?
Eukaryotes
3 main protozoa?
ameba, flagellates, sporozoa
3 main parasite categories?
single celled protozoa, multicellular helminths, macroscopic ectoparasites
3 main helminths?
nematodes/roundworms, cestodes/tapeworms, trematodes
Why are antiparasitic agents potentially toxic?
targeting eukaryotic processes
Main ectoparasite subcategory?
arthropods (i.e. ticks, fleas, lice)
What category of parasite can act as vectors or disease agents?
ectoparasites
How are protozoa categorized?
by mode of movement
What do all sporozoa have in common?
organisms whose adult stage is not motile
What kind of parasite is plasmodium?
sporozoa
What kinds of parasites are giardia and trichomonas?
flagellates
What are the life cycle stages of protozoa?
trophozoite and cyst, some may have additional sexual stages
What do trophozoites do?
they’re motile, feeding, and reproducing
What do cysts do?
they’re thick walled and surviving in the environment
What life cycle stage of protozoa is associated with pathogenicity?
trophozoite
Definitive vs intermediate host?
Definitive = where parasite completes sexual phase; intermediate = parasite lives asexually
Define reservoir
host that serves as a source of parasite transmission to the population of interest
In what stages of life are flukes infectious?
egg, larva, and adult
In what stages of life are tapeworms infectious?
larva and adult
In what stages of life are nematodes infectious?
larva and adult
2 kinds of larvae?
rhabditiform and filariform
Which larvae is “early stage”
rhabditiform
Which larvae is “later stage”
filariform
Which larvae is infectious?
filariform
What is the innate human immune response to parasites?
high eosinophil count/Eosinophilia
Are eosinophils effective at combating parasitic infections?
No - eukaryotic parasites have evolved to supress, avoid, and deflect
What is meant by the “hygiene hypothesis?”
As we decrease the incidence of parasites with modern, more sterile environments, we increase the risk of inappropriate immune response to self-antigens and environmental allergens (immune disease and allergies increase)
Helminths vs protozoa - which is considered a more cosmopolitan infection and which is associated with poor countries?
Cosmopolitan = protozoans (i.e. Giardia) Poor = helminths (i.e. tapeworms)
Geographic distribution of vector borne parasites?
Corresponds to geographic distribution and seasonal activities of their arthropods
Explain how local intestinal disease works. What kind of organism involved?
trophozoites attach at brush border and injure/irritate, villous atrophy/damage of microvilli or tight junctions may occur, symptoms range from asymptomatic to diarrhea, may even be chronic syndrome