Handout 1 Flashcards
ANIMAL PARASITE
Uni- or multicellular organism, which - constantly or temporarely - lives on or in a different species for feeding and/or reproduction, while making harm to the latter.
We can differentiate between ecto- and endoparasites according to their location outside or inside the host, respectively.
(FINAL) HOST
Higher organism, on which or in which a parasite species occurs, or finds suitable conditions to reach full (sexual) maturity. The ‘final host’ (or definitive host) term is relevant to the life cycle of those parasites, which also have intermediate host.
INTERMEDIATE HOST
An animal species, in which a (sexually) immature (infectious) stage of the parasite can develop, and which is necessary for the completion of the parasite’s life cycle.
PARATENIC HOST (RESERVOIR)
An organism, in which the infectious larvae (or developmental stages) stay alive and accumulate, therefore prolonging the lifespan of the larvae and promoting the infection of the final host, but which is not obligatory for the completion of the parasite’s life cycle.
VECTOR
An organism spreading the parasite either by carrying it (as a mechanical vector) or also making suitable conditions for its development (as a biological vector, necessary for the parasite to complete its life cycle).
SPECIFIC HOST
Host species suitable for the establishment of the parasite. a. Ordinary host: in its normal physiological conditions.
b. Occasional host: only when predisposing factors make it possible.
STENOXENOUS PARASITE
It can only establish in one (or very closely related) host species.
EURYXENOUS PARASITE
It can infect a wider range of host species.
HOMOXENOUS PARASITE
Parasite, of which the life cycle involves one host species.
HETEROXENOUS PARASITE
Parasite, of which the life cycle involves more than one host species.
HOST RANGE
The range of those species, in which the (sexually) mature stage of a given parasite can develop.
INERMEDIATE-HOST RANGE
The range of those species, in which the (sexually) immature stages can develop.
HOST SUSCEPTIBILITY
Consists of those factors, which make a host species suitable for the establishment of the given parasite.
BREED (INNATE or GENETIC) RESISTANCE
The genetic insurability of a certain species/breed/ strain/individual for the establishment of the given parasite.
AGE RESISTANCE
The host species is susceptible for its specific parasite only when young.
ACQUIRED IMMUNOLOGICAL UNRESPONSIVENESS
When the host species is unable to mount a successful immune response against the parasite (because it became tolerant to the antigenic parasite derivants at an early age, these being recognized as self).
INFECTIVE IMMUNITY (PREMONITION)
Acquired immunity, which necessitates the presence of the parasite for its sustenance.
ACQUIRED IMMUNITY
Specific defence mechanism against the parasite evoked by its antigenic substances (which frequently results only in a partial protection against homologous reinfection).
INVASION (INFESTATION)
The entering of the parasite into (onto) the host species.
a. Active: when the parasite actively invades the host by migration, contact or retroinfection (this latter from
the same individual).
b. Passive: when the parasite is taken up by the host with the forage, water, air or (sexual) contact. This also
might involve transmitters (instruments, iatrogenic intervention, etc.).
INFECTION BY VECTORS
The higher organism transmits (inoculates or carries) the parasite into or onto the host.
PRENATAL (TRANSPLACENTAL) INFECTION -
When a certain stage of the parasite can infect the foetus of the pregnant host via the placental circulation.
COLOSTRAL OR GALACTOGENIC INFECTION -
the parasites are taken up by the suckling via the colostrum or milk of its mother.
HORIZONTAL INFECTION
Spreading of the parasite between individuals within the same generation.
VERTICAL INFECTION
Spreading of the parasite between individuals of different generations.