Principles of parasitism

Question 1

commensalism

Answer 1

reproduce in the host but not a true parasite

Question 2

parasitism

Answer 2

interferes with host
metabolic dependency of one organism upon a second

Question 3

fitness characterized by parasite’s ability to:

Answer 3

become established in host
resist environmental stresses
survive host defenses
reproduce and disseminate its progeny

Question 4

obligatory parasite

Answer 4

cannot complete its lifecycle without spending part or all of its time on or within a host
may use successive series of different hosts
may have free-living stages

Question 5

facultative parasite

Answer 5

become parasitic when eaten or opportunistically enter host

Question 6

endoparasite

Answer 6

organism living within host environment

Question 7

ectoparasite

Answer 7

organism living on host

Question 8

aberrant parasite

Answer 8

organisms found in locations where they do not normally occur
-do not mature/ facilitate transmission, result in disease state

Question 9

accidental/ incidental parasite

Answer 9

enter or attach to host species different from ones which normally associated
repeated successful colonization can develop new host association
may not survive on host

Question 10

pseudoparasite

Answer 10

diagnostic parasite stages that resemble protozoan cysts in feces, blood or urine

Question 11

hyperparasite

Answer 11

when parasitic organism is host to another parasite species

Question 12

definitive host

Answer 12

parasite attains reproductive maturity
circulation or passage of progeny capable of colonizing additional host species

Question 13

intermediate host

Answer 13

larval or intermediate stage parasite must undergo development to become infective for final host
often required developmental stage for completion of life cycle

Question 14

paratenic host

Answer 14

host used by larvae/ intermediate stage to facilitate transmission to final host
do not undergo development!!
bridges ecological gap between passage of infective stages and successful transmission

Question 15

reservoir host

Answer 15

maintain a parasite in population at sufficient levels to facilitate its transmission between hosts
may be definitive, intermediate, or paratenic
emphasis on population rather than individual!!

Question 16

vectors

Answer 16

organisms that facilitate transmission of infective parasite stages between individuals

Question 17

direct lifecycle

Answer 17

parasites infect host indirectly
stages passed from host in feces/ other tissues
infective to another definitive host
may require period of development to infective stage

Question 18

indirect lifecycle-obligate

Answer 18

require intervention of intermediate host
stages passed from host in feces/other tissues
infective to intermediate host
requirement for development to infective stage
indirect transmission to definitive host
may involve paratenic host

Question 19

indirect lifecycle-facultative

Answer 19

indirect transmission to definitive host
optional intervention of intermediate/ paratenic host
stages passed from host in feces/ other tissues
infective to definitive host or optional host

Question 20

horizontal transmission

Answer 20

parasites colonize susceptible individuals by usual routes
infection across different generations of host population not required

Question 21

vertical transmission

Answer 21

transmission of parasites from mother to offspring by transplacental or lactogenic routes
trans-generational requirement

Question 22

high specificity for host

Answer 22

limited number of hosts capable of completing lifecycle

Question 23

low specificity for host

Answer 23

wide variety of species capable of hosting parasite
typical of intermediate and paratenic host

Question 24

endemic

Answer 24

normal or usual distribution of parasites in host population or geographical area

Question 25

epidemic

Answer 25

excess number of parasite cases, far exceeding normal distribution

Question 26

prevalence

Answer 26

occurrence of parasite in a population defined by time and space

Question 27

incidence

Answer 27

rate at which new cases are added to new host population defined by time and space

Question 28

roundworm characteristics

Answer 28

bilaterally symmetrical, cylindrical and elongate body size ranges worm-like bodies covered w cuticle longitudinal muscles only females larger and males w/ elaborate apparatus pseudo-coelomate

Question 29

cuticle fxn

Answer 29

collagenous tissue that resist fluid loss and dehydration support as flexible exoskeleton

Question 30

pseudo-coelomate

Answer 30

cross-sectional view "tube w/in tube" fluid filled body cavity under hydrostatic pressure complete digestive tract w defined oral opening female repro tract has varying ovary morphology