Parasites Flashcards
May be exposed to a zoonotic organism by:
Inhalation Contact with broken skin Ingestion Contact with eyes and mucous membranes Accidental inoculation with a needle
Parasite
lives in or on another organism and benefits by deriving nutrients at the organism’s expense
Host
an animal or plant on or in which a parasite or commensal organism lives
Primary/ definitive host
A host in which the parasite reaches maturity and reproduces sexually
Secondary host/intermediate host
A host that harbors the parasite only a short transition period
Where some developmental stages are completed
Mosquitos with heartworm
Ectoparasite
A parasite that lives on the exterior of its host
Fleas, lice, ticks, mites
Endoparasite
A parasite that lives within the body of its host
Nematodes, roundworms, heartworms
Obligatory Parasite
Only survives with a host
Periodic Parasite
A parasite that visits the host for short periods
Mosquito
Incidental Parasite
Invades a host that it normally does not
Heartworms and humans
Facultative Parasite
Free-living organisms that can become parasitic if given the opportunity
Maggots
Aberrant Parasite
A parasite that migrates from its usual site of infection
Ocular larva migrans
Pseudoparasite
Creatures or objects that are mistaken for parasites
Grain mites
Paratenic host
A special intermediate host in which a parasite does not undergo any development
Remains arrested in the hosts’ tissue
Toxoplasma gondii
Reservoir host
Can harbor a pathogen indefinitely with no ill effects
May be reinfected several times
Dead-end hosts
A type of intermediate host that does not allow the transmission to the definitive host
Prevents completion of the life cycle
Host of predilection
preferred host
Protozoans
Kingdom Protista
Unicellular organisms
Single-celled
Most are free-living
Parasitic Protozoans
Flagellates
Amoebe
Ciliophora
Apicomplexa
Flagellates
Flagellum-long whip-like appendage
Trophozoite-moving form
Pear or bullet-shaped
Reside in blood, lymphatic fluid or cerebrospinal fluid
Amoebae
Motility: Pseudopodia
A temporary protrusion of the surface for movement and feeding
Ciliophora
Motility: Means of tiny beating hairs
The trophozoite is the moving form of protozoa
Kidney-bean shaped
reside in intestinal tracts
Apicomplexans
Motility: internal organelles that cause locomotion via undulations
Banana, comma and boomerang-shaped
Causes anemia
Babesia, toxoplasina gondii, toxomplasma gondii
