Parasitology Flashcards
Define parasite
A smaller organism that lives on or in and at the expense of a larger organism (host).
What is the phylum and class of “roundworms”?
Phylum nemathelminths
Class Nematoda
What is the phylum and class of “tapeworms”?
Phylum platyhelminthes
Class Cestoda
What is the phylum and class of “flukes”?
Phylum platyhelminthes
Class trematoda
Nematodes:
- Free-living or parasitic?
- Shape/conformation?
- Ailmentary canal present?
- Separate sexes or hemaphroditic?
- Both free-living and parasitic
- Elongate/cylindrical
- Ailmentary canal present
- Separate sexes
Cestodes:
- Shape/conformation?
- Alimentary canal present?
- Separate sexes or hermatphroditic?
- Flat body
- No alimentary canal
- Hermaphroditic
What is a scolex and who has one?
Scolex is the “holdfast organ” in cestodes. It’s the head
What is a strobila and who has it?
Strobila is the body with proglottids found in cestodes
What is a proglottid and who has it?
Egg packets found in cestodes
Trematodes:
- Shape/conformation?
- Separate sexes or hermaphroditic?
- Dorso-ventrally flattened - Leaf-like
* separate sexes
Common name for diptera.
Flies
Common name for siphonaptera
Fleas
Common name for Phthiraptera
Lice
What are the physical characteristics of insects?
Adults have 3 pairs of legs
3 body segments: head, thorax and abdomen
Antenna present
What are the physical characteristics of adult arachnids (acari)?
4 pairs of legs
2 body segments: cephalo-thorax and abdomen
No antennae, but palps
How many pairs of legs are found in nymph acari? Larvae acari?
4 pairs in nymphs
3 pairs in larvae
How are protozoa classified?
Classified based on their mode of locomotion.
What are the ways in which protozoa accomplish locomotion?
Pseudopodia
Flagella
Gliding movements
Cilia
Define Definitive Host.
Harbors adult (sexual) stage of the parasite
Define Intermediate Host
Harbors larval (asexual) stage of the parasite
Define Incidental Host
An unusual host, unnecessary for the maintenance of the parasite in nature.
In what ways can parasites cause mechanical tissue damage?
Blockage of internal organs
Pressure atrophy
Migration through tissues
Give examples of toxic parasite products
Destructive enzymes Endotoxins Toxic secretions (tick paralysis)
Define premunition
A type of acquired immunity in which the host is able to prevent superinfection by keeping parasite numbers in check without eliminating the infection (i.e. marlia, toxoplasmosis)
Define concomitant immunity
A type of acquired immunity in which the parasite elicits a protection against reinfection, but the parasite itself remains in the host, unaffected by the immune response (i.e. schistosomiasis).
