Week 2 Flashcards
How do parasites differ from their free living counterpart?
sensory organs, locomotive organs, digestive tract, adherence location, reproduction
ectoparasites: flea
adapted to be blood suckers, no wings, simple eyes, compressed bodies, and backward projecting spines, hairs to feel vibration
endoparasites: tapeworm
no digestive tract, simple eyes, flat bodies, suckers for attachment, hermaphrodites
major rule for parasites
don’t eat to live but eat to reproduce
why do parasites depend on the host for reproduction?
need to reproduce fast and efficiently and spread stages to other hosts
parasite reproductive organs
high complexity and volume
stage specific adaptation is required because
there are different stages in intermediate/definitive host and environment, and some parasites have migrating stages in one host
migratory stages in one host
stages are guided by chemical signals in typical hosts, resistant to hostile micro-environment
stationary ectoparasites environment
little thermal stress, little desiccation, stable habitat
what does it mean if the parasite has a stable habitat?
limited physiological challenges by host
what do micro-environments provide?
many and highly concentrated nutrients
anaerobic metabolism (may be host dependent)
high rates of glucose utilization, low amino acid catabolism, no or low beta-oxidation of fatty acids
ectoparasite physiology
immune and chemokine factors may limit host spectrum, stationary parasites with limited survival without host access, often have hidden antigens to enhance hosts tolerance
ectoparasites on atypical hosts
atypical hosts would have a more severe immune response
changes in parasitized hosts: adaptive changes
to be discriminated from adverse reactions, like damage, disease, and malfunction, to parasites
