a kind of symbiosis in which one symbiont (commensal) is benefited, 

while the other (host) is neither harmed nor helped by the association

a kind of symbiosis in which both symbionts are metabolically dependent 

upon each other, and both are benefited by the association

a kind of symbiosis in which the parasite is metabolically dependent on the 

host, and may be harmful to the host by depradation or damage

a parasite which is completely dependent on the host for its 

existance during all or part of its life

a parasite which is not completely dependent on the host for its 

existence.  Usually completes the life cycle as a free-living organism, but can 

complete part or all of its life cycle in or on a host

a parasite which has one type of host (lives within a single host) 

in its life cycle

a parasite which contacts its host to feed then 

leaves

a host in which the parasite is commonly found and in 

which the parasite can complete its development (or the appropriate phase of its 

development necessary for completion of its life cycle).

a host in which the parasite is not commonly found, but is suitable for 

the parasite's development.  (sometimes becomes a dead-end host)

a host in which the parasite cannot complete its development or the 

appropriate phase of its development

a host in which the parasite undergoes sexual reproduction or reaches 

the adult stage.  (if no sexual reproduction, then the stage that is most important 

to humans)

a host in which the parasite survives, but in which no 

development occurs. It accumulates and maintains stages of the parasite but is 

essential to the life cycle

a living vector which is essential for the development and life cycle of 

the parasite and in which the parasite undergoes morphologic change and/or 

multiplication.  3 classes: 

   Propagative - parasite multiplies, but doesn't change morphologically 

   Cyclopropagative - parasite multiplies, undergoes cyclic morph changes 

   Cyclodevelopmental - parasite changes, but doesn't multiply

any host in which the parasite lives and is available for transmission to 

another susceptible host

a vector which is not essential for the development or life cycle of 

the parasite. May be living or non-living

a life cycle in which there is a definitive host and one or more 

intermediate hosts involoved

a life cycle involving the alternation of free-living and parasitic 

generations

a life cycle in which all generations are parasitic or free-living.  

There is no alternation (or very little) between the two

transmission in which the host/parasite contact is more or less 

accidental; usually by accidental ingestion or mechanical vectors

reinfection by the progeny of a parasite while they are still in the body of 

the host

reinfection by the progeny of a parasite which hatch on the skin and 

reenter the body of the host

a new, superimposed infection of an individual host that already bears 

infection by the same species of parasite

the period of time from infection of a 

host  with a parasite until one can demonstrate that the host is infected by 

finding a stage of the parasite (egg, larvae, etc.) in or from the host. 

the period of time from the first demonstration of a parasite in or from a 

host until one can no longer demonstrate that the host is infected

resistance in which exposed hosts are more susceptible to 

infection by a parasite as older individuals than when they are younger

resistance of a host to superinfection which persists only as long as the 

parasites which provoke it survive and are present in the host

living in feces.  Usually applied to non-parasites or pseudoparasites which 

may be ingested and passed through the intestinal tract without having infected 

the animal.