Parasitology Flashcards
What is the definition of parasitism?
An intimate relationship between 2 organism in which one (parasite) lives on, at the expense of the other (host).
Name the common names for the following endoparasites:
1) Helminths
2) Nematodes
3) Cestodes
4) Trematodes
1) Worms
2) Roundworms
3) Tapeworms
4) Flukes
What is the difference between a direct and an indirect lifestyle of parasites?
A direct lifestyle is when a parasite is transmitted from one host to the next
An indirect lifestyle is where a parasite requires more than one type of host species to complete their lifestyle.
What is an intermediate host?
A host where the parasite remains for the immature stages of its life to grow and develop
What is a definitive host?
A host where parasites reach sexual maturity
What is a vector?
An organism that plays an active role in transmitting a pathogen from one species to another
What is a transport host?
A transport host mechanically transfers a parasite to another host
What is a reservoir host?
A host that harbors parasites that infect other animals.
What is the 80%/20% rule?
Most of the parasite population is present in only a few hosts. 80% of parasite burden is found in 20% of hosts.
What are 5 advantages of the parasitic lifestyle?
1) Once a host is found, no further looking required
2) Food is permanently available
3) Protection from outside environment
4) No need fr dispersal - more energy and time for reproduction
5) Many can survive weeks, months or years even if no host is present.
What are 2 disadvantages of the parasitic lifestyle?
1) Parasites need to overcome the immune system and host physiology
2) Not easy and most parasites become host specific.
What are 3 routes to invade hosts?
1) Skin penetration
2) Ingestion
3) Inoculation
What are the 3 types of helminth?
Cestode (tapeworm)
Nematode (round worm)
Trematode (fluke)
What is the general morphology of a cestode?
No mouth or gut
Limited metabolism
Relies on energy from host - absorbs glucose.
Describe the function and size of the scolex in cestodes.
The scolex (head region) is less than 1mm in length. Point of direct contact of adult cestodes to host tissues. Attaches via suckers and some scoleces also have a ring of hooks. Often left behind after treatment.
