Definitions: Exam 1 Flashcards
Direct life cycle
single definitive host, no intermediate host,
Indirect Life Cycle
one or more intermediate host in addition to definitive host
Symbiosis
living together
Commensalism
one benefited, other neutral no harm or benefit
Mutualism
both benefit, usually obligatory, cannot survive without the other
Phoresis
traveling together, no physiologic or biological dependence
Obligatory parasites
cannot complete lifecycle without host
Facultative parasites
not usually parasitic but can become so if accidentally eaten or enter a wound or other orifice
Accidental parasites
do not survive in the wrong host
Temporary or intermittent parasites
visits the host from time to time for food.
mosquitoes, bed bugs
Definitive host
parasite reaches sexual maturity, often vetebrates
Intermediate host
needed for development, sexual maturity not reached
Paratenic host
bridge ecological gap, no development but parasite stays alive
Reservoir host
a host which allows the pathogen to live, and possibly grow, and multiply.
animal harboring that can be transmitted to humans
Zoonoses
a disease which can be transmitted to humans from animals.
Apicomplexans
Have an apical complex, can bore into host cell
Trophozoites
Active, feeding, multiplying stage
In parasitic species this is the stage usually associated with pathogenesis
Cysts
are stages with a protective membrane or thickened wall
common in organisms that may encounter harsh conditions
Cysts that must survive outside the host usually have more resistant walls than cysts that form in tissues
Specific gravity
the density of that object divided by the density of water.
necessary in fecal floatations
Media
have to choose media with proper specific gravity
Sheather’s sugar
specific gravity of 1.27
enough to float any ova
Excystation
The stage in the life cycle of a parasite in which it escapes from a cyst (after being swallowed by its host)
Encystment
the formation of a cyst. The process of becoming enclosed by a cyst.
Encystment
Prepatent period
the period between infection with a parasite and the demonstration of the parasite in the body especially as determined by the recovery of an infective form (as oocysts or eggs) from the blood or feces.
before symptoms
Flagellates
a cell or organism with one or more whip-like appendages called flagella
Sporulated oocysts
The process by which immature (noninfective) coccidian oocysts develop into the mature, infective form.
resistant to adverse environmental conditions and can survive as long as one year in moist, protected environments
Percutaneous
Infection via skin penetration
Transmammary
Arrested larvae can become reactivated during parturition and as a result can be transmitted to puppies through the bitch’s milk.
Transplacental
the exchange of nutrients, waste products, drugs, infectious organisms, or other substances between the mother and the fetus.
Tissue cyst
In the human host, the parasites form tissue cysts, most commonly in skeletal muscle, myocardium, brain, and eyes; these cysts may remain throughout the life of the host.
Parthenogenic
a natural form of asexual reproduction in which growth and development of embryos occur in a gamete without combining with another gamete.
Homogonic
being or characterized by a course of development in which one generation of parasites immediately succeeds another.
Heterogonic
being or characterized by a course of development in which a generation of parasites is succeeded by a free-living generation.
Hyperinfection
repeated reinfection with larvae produced by parasitic worms already in the body due to the ability of various parasites to complete the life cycle within a single host compare autoinfection.
Hexacanth embryo
the embryo of tapeworms of the subclass Cestoda, such as Taenia saginata, characterized by three pairs of hooks used for penetration through the gut of an intermediate host.
Metacestode
the larval stage of a tapeworm, found in an intermediate host.
Proglottids
each segment in the strobila of a tapeworm, containing a complete sexually mature reproductive system.
Species specificity
the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species
Rostellum
a small beaklike process, such as the hooked projection from the top of the head in tapeworms or the outgrowth from the stigma of an orchid.
Cysticercoid
the larval stage of certain tapeworms
Cysticercoid
the larval stage of certain tapeworms
Cysticercus
a small, bladder-like cyst
Cysticercus
a small, bladder-like cyst
Wolbachia sp.
harbored in worms
sporocyst
In adult ticks, sporocysts develop within oocysts and dog becomes infected after eating a tick
sporozoite
constitutes the first form of the malaria parasite entering the human body
upon ingestion of sporocysts, sporozoites can either enter GI cells or disseminate to other tissues
Diplomonad
a group of flagellates, most of which are parasitic.
Immunodiagnostics
tests to detect antibodies and parasite antigens
Baermann
sedimentation for heavier eggs
McMaster’s
fecal floatation, dilution technique
Knott’s test
used to detect and identify microfilariae of filarid nematodes in blood.
heartworm
Merogony/schizogony
A form of asexual reproduction whereby a parasitic protozoan replicates its own nucleus inside its host’s cell and then induces cell segmentation; schizogony
Gamogony/gametogony
Gamogony/gametogony
sporogony
the asexual process of spore formation in parasitic sporozoans.
Specific features of
Nematodes
- Buccal cavity: is modified in the form of a hollow spear, adapted to penetrate and withdraw the contents of host cells.
- Bursa: a lobular modification of the male posterior end in some groups of nematodes which is highly elaborated in strongylid nematodes
- Dioecious: having individuals of separate sexes.
Specific qualities of:
Trematodes
- Monoecious: having both the male and female reproductive organs in the same individual
- Dioecious: having the male and female reproductive organs in separate individuals.
- Acetabula: sucker
Cestodes
Proglottids: segments with reproductive parts
strobila: a more developed form of a cysticercus
scolex: holdfast organs
rostellum: beak like head
Protozoans
- Flagellates
- Kinetoplasts: flagellated protozoans, which are unicellular eukaryotic organisms.
- Cyst
- Trophozoite: animal that feeds
