Parasitology Flashcards
what is a parasite
an organism which exploits another organism to stay alive
how does an organism become a parasite?3
bring nothing to relationship
neutral or harmful never positive
depend on host for food , energy and incubation
what are the two types of parasites
ecto- outside
endo-inside
4 advantages of being parasitic
protected from outside world
provided with nutrients
can travel great distances in comparison to size
devote lots of time to reproduction
7 disadvantages of being parasitic
must go where host goes diet is detemined by host difficult to enter host migrate through lots of tisue to reach ideal location difficult to exit host if host dies you die encounter formidable defense mechanisms
what are protozoans
unicellular eukaryotes
two features of protozoans
lack a cell wall and have at least one motile stage in life cycle
what is trophozite
the active growing stage of a protozoan parasite distinct from the dormant encysted stage
what is a sporozoite
motile, enfective stage that results from sporogony of dormant oocysts
what are the two methods od parasite entry
route- ingestion
direct penetration- bites , transplacental , organism directed
what are the 6 key factors of parasite pathogenicity
infective dose and exposure penetration of anatomic barriers attachment replication damage disruption and inactivation of host defences
what does DALY stand for
disability adjusted life year
what is DALY
sum of years of life lost due to premature mortality and years lost due to disability = one daly is one year of healthy life lost
what are 5 common parastites for human disease
amoeba flagellates coccidia nematodes trematodes
what do aemobas cause
amoebic dystentery- occurs by ingestion through food or water
excystation in small intestine causing tissue necrosis
