Parasitology - Exam 3 Flashcards
definition of parasitism
non-mutual symbiotic relationship between species where only one benefits
key concepts of parasites
live in/on host, smaller than host, reduce host biological fitness, don’t kill their host normally, reproduce faster than host, use host for food/H2O/heat/habitat/transmission
8 different types of host include:
host specific, broad host spectrum, definitive/final host (DH or FH), intermediate host (IH), biological vector, paratenic host (PH), transport host, aberrant/dead end host
DH/FH
main host, sexual reproduction occurs within
IH
other immature stages of a parasite
PH
not required for life cycle, survival, transmission
transport host
PH & IH can be these, help move parasite from A to B
aberrant/dead end host
not the host the parasite belongs to, weird behavior, unable to properly develop/reproduce
modes of infection
oral, skin penetration, injection, transplacental
direct life cycle example
1 host; worms present in animal, eggs shed in feces, goes into environment, animal eats feces & gets infected
indirect life cycle example
2+ hosts; worms in cat, eggs in feces, mouse eats feces, cat eats mouse
sexual reproduction advantage
genetic diversity
sexual reproduction disadvantage
longer life cycle, M & F parasites required
asexual reproduction advantage
one (amplification), short life cycle
asexual reproduction disadvantage
no genetic diversity
benefits from the host: survival
heat, food, H2O, habitat,
arrested development/hypobiotic stage
dormant, stop developing until parameters (temperatures) are right
predilection site
preferred site in/on the host, each stage can have 1 food source, able to avoid immune system
aberrant site
site in/on host which isn’t normal i.e.: eyeball
parasite factors
number, location, migration, transmission (how it’s entering the animal), activity, production of toxic products,
host response
previous exposure, type of host response (inflammatory, immune), nutritional status (malnourished = more likely to become ill), age of the host (size = baby vs adult)
environmental factors
increase parasite, increase hypobiosis, decrease immunity, management, geographical location, weather
-iasis
presence of parasite; healthy, no clinical signs
-osis
disease caused by parasite
helminth
worm, parasitic and nonparasitic, live extracellularly in GI tract & organs, passive/active ingestion of nutrients, stored as glycogen
helminth sexual reproduction
male or female, hermaphrodite, oviparous (egg laying), viviparous (lay live young), don’t multiply within host (offspring must leave host), only way to get one is to eat one
