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70 terms

parasitology

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Symbiosis
interaction between two organisms of different species, living together in intimate association. Implies no mutual or unilateral benefit or metabolic dependency
Commensalism
a kind of sybiosis in which on symbiont (the commensal) is benefited, while the other (host) is neither helped nor harmed by the association. The host provides food and or shelter to the commensal, which lives without benefit or harm to the host
Mutualism
a kind of symbiosis in which both sybionts are metabolically dependant upon each other, and both are benefited by the association
Parasitism
a kind of sybiosis in which one symbiont (the parasite) is metabolically dependant on the other (host) and at the same time, may be harmful to it by deprivation or damage
Phoresis
a kind of symbiosis in which one symbiont (phoront) is mechanically carried about by its host. No metabolic interaction or dependancy occurs
Parasite
an organism which lives at least part of its life cycle on or with in another organism (host) upon which it is metabolically dependant and to which it may cause harm. In parasitology or from medical point of veiw, it is restricted to animal agents, i.e, protozoa, helminths, and arthropods
Ectoparasite
a parasite which lives on the body surface of the host
Endoparasite
a parasite which lives within the body of host
Obligate parasite
a parasite which is completely dependent on the host for its exsistance during part or all its life cycle
Facultative parasite
parasite which is not completely dependent on the host for its exsistence. It can and usually does complete its life cycle as a free-living organism, but, alternatively, can complete part or all its life cycle in or on the host
Monoxenous (homoxenous) parasite
a parasite which has one type of host (lives within single host) in its life cycle
Heteroxenous (euryxenous) parasite
a parasite with two or more types of hosts (lives in more than one host) in its life cycle
Temporary (intermittent) parasite
a parasite which contacts its host only to feed then leaves
Hyperparasite
a parasite which is parasitic on or ith in another parasite
Host
a living plant or animal which harborsand or gives sustenance to a symbiont
Natural host (typical host)
a host which the parasite is commonly found and which the parasite can complete its development (or appropriate phase of its development neccessary for subsequent completion of its life cycle
Accidental host
a host in which the parasite is not commonly found. neverless, it is one suitable for the parasite's development. In some instances, the accidental host beomes the dead end host
Aberrant host
a host in which the parasite cannot complete its development or the appropriate phase of its development
Definitive host
a host in which the parasite undergoes sexual reproducion or reaches the adult stage. If there is no sexual reproduction in the life of the parasite, the host most important to humans is the definitive host
Intermediate host
a host which harbors the asexual or immature stages of a parasite and which in some stage of its development of the parasite takes place
Paratenic host (transport host)
a host in which a parasite survives, but in which no further development of the parasite takes place. It accumulates and maintains stages of the parasite butis not essential to the life cycle
Dead end host
a host in which the parasite reaches an end point and is unable to continue its life cycle
Reservoir host
any host in which the parasite lives and is available for transmission to another susceptible host. In parasitology, the term usually refers to a host which harbors a stage of the parasite similar to that found in the natural host. It is not the most important host
vector
any agent, either animate or inanimate (such as wind,water,or arthropod) that transmits an infectious organism
Biological vector
a living vector which is essential for the development and life cycle of the parasite and in which the parasit undergoes morphologic change and/or multiplication
Mechanical vector
a vector which is not essential for the development or life cycle of the parasite: may be living or non living
Direct life cycle
a life cycle in which there is only a definitive host, with no intermediate hosts involved
Indirect life cycle
a life cycle which there is a definitive host and one or more intermediate hosts involved.
Heterogonic life style
a life cycle involving alternation of parasitic and free living generations
Homogonic life style
a life cyclein which all generations are parasitic or all are free living. there is no (or little) alteration of the two
Active transmission
transmission in which either an active, aggresive parasite itself seeks out the host and enters it or a biological vector actively seeks out the host and brings the parasite to it
Passive transmission
transmission in which the host/parasite contact is more or less accidental; usually accidental ingestion of the parasite or due y mechanical vectorsspread b
Stage
any particular form in the life cycle of a parasite which can be distinguished from all of its other forms
Infective stage
that stage in the life cycle of a parasite which is capable of producing infection of a host
Larva
any pre-adult stage in the life cycleof an organism, other than the egg, that is morphologically distant from the adult
Autoinfection
reinfection by the progeny of a parasite while they are still with in the body of the host
Retroinfection
reinfection by the progeny of a parasite which hatch on the skin and reenter the body of the host
Superinfection
a new, superimposed infection of an individual host that already bears infection by the same species of parasite
Prepatent period (biological incubation period)
the period of a time from infection of a host with a parasite until one can demonstrate that the host is infected by finding a stage of a parasite (eggs, larva, ect) in or from the host
Patent period
a period of time from first demonstration of a parasite in or from the host until one can no longer demonstrate that the host is infected (parasite dies from natural causes)
Clinical incubation period
a period of time from infection of a host with a parasite until clinical signs are apparent
Natural resistance
inherit resistance of a species against infection with a certian strain or species of parasite
Age resistance
resistance in which unexposed hosts are more susceptibe to infection by a parasite as young animals than they are when they are older
Reverse age resistene
resistance in which unexposed hosts are more susceptible to infection by a parasite as older animals than they are when they are younger
Premunition
resistance of a host to superinfection which persists only as long as the parasites which provoke it survive and are present in the host. It is resistance conferred by a still exsisting infection, the organism of which are not destroyed by the resistance. It may be complete or partial resistance
Host specificity
the restriction of a parasite to one or more kinds of hosts; the degree to which a parasite is able to mature in more than one host species
Parasitemia
a presence of parasite stages in the circulating blood
Coprozoic
living in feces. Usually applied to non parasites or pseudo-parasites which may be ingested and passed through the intestinal tract without having infected the animal
Copraphagy
the eating of feces
Parasitiasis
the parasite is resent on or with in the host and is potentually pathogenic; however the animal does not exhibit outward clinical signs of disease
Parasitosis
the parasite is present on or within the host and does produce obvious injury or harm to the host. The host exhibits obvious outward clinical signs of clinical paratism
Ectoparasite
parasites wich live on the body of the host
Endoparasite
parasites that live within the host
Erratic or aberrant parasites
parasites that wander away from their usual sites of infection
Incidental parasite
a parasite can occur in a host in which it usually does not live
Facultative parasite
organisms that are free-living in nature and become parasitic in certain hosts
Obligatory parasite
parasites that must lead a parasitic existence. Most of the parasites that affect domestic animals are obligatory parasites
Periodic parasite
parasites that mke short frequent visits to the host to feed.
Predator-prey
short term relationshipin which one symbiont benefits at the expense of the other ( cat and mouse)
Phoresis
the smaller member of the relationship is mechanically carried about by the larger member (flea on a dog)
Mutualism
association in which both organism in relationship benefits
Commensalism
association in which one symbiont benefits and the other niether benefits nor is harmed
Parasitism
association that exists between two organisms of a different species in which one member (parasite) lives on or within the other member (host) and may cause harm. Parasite is metablically dependent on host
Homoxenous or monoxenous parasite
parasite that will infect only one type of host
Stenoxenous parasite
parasite with very narrow host ranges
Euryxenous parasite
parasites with very broad host ranges
Qualitative method
reveals whether parasites are present or not
types of qualitative method
fecal floatation, centrifuge, direct smear
Quantitive method
indicates the number of eggs or cysts present in each gram 0f feces. Indicates the number of adult parasites with in the host
types of quantitive methods
stolls-egg counting technique, modified Wisconsin sugar flotation method,McMaster technique