Host parasite associations Flashcards
Key parasitic characteristics
- metabolically reliant on host
- lives in or on another species
- may not necessarily harm host
- usually smaller than host
Distinguish between micro and macro parasites
MICRO - do not reproduce in their definitive hosts
- short generation time
- host is the unit of study
- often lasting immunity
MACRO- reproduce in definitive hosts
- long generation time
- no lasting immunity
- parasite unit of study
Product of disease/ parasite interaction
- elevated temperature (fever)
- reduced food intake
- immune response
- decreased activity
- pain sensitivity
3 ways to classify parasites
1) MACRO vs MICRO
2) Taxonomically
3) transmission strategy
Protozoa are single celled (a) consisting of 4 classes, what are those classes? b)
EDDIE AND EVE DUCKED
a) eukaryotes
b) euglenozoa (extracellular)
apicomplexa (intracellular)
Entamoeba (amoeba like growth form)
Diplomonad (no mitochondiria)
Helminth characterisitcs
- metazoan parasitic worms
- non- monophyletic group
- have complex lifestyles
4 forms of Helminth
- nematoda (roundworms)
- trematoda (blood flukes)
- cestoda (tapewormds)
- acanthocephalans (thorny headed)
DEFINE EACH
a) Direct/ simple/ monoxenic lifecycles
b) Indirect/ complex/ heteroxenic lifecycles
a) can complete development and reproduction using one host
b) requires 2 or more hosts to complete development and reproduction known as the intermediate stages
Nematode worms lack (a) mechanisms and enter hosts through skin (b).
a) holdfast
b) penetration
Distinguish between monogenean and digenean trematodes
mono- are fish ectoparasites with 2 suckers
dio- require multiple hosts
Cestodes inhabit vertebrate (a) and attach to hosts with head like (b).
c) How do adults absorb nutrients as they lack a gut?
a) guts
b) scolex
c) through their body surface
Acanthocephalans have thorny a (a) which is exerted into (b) walls.
a) proboscis
b) gut
Why are non-parasitic arthropods crucial in the life cycles of many parasites?
- BLOOD FEEDING
- vectors or intermediate hosts
Why be parasitic?
- constant source of processed food
- shelter from elements
- host movements help parasite dispersal
- presence of same species make finding mates easier
Using examples, distinguish between facultative and obligate parasites.
FACULTATIVE - not always parasitic, doesn’t NEED host to complete life cycle
eg. fungi
OBLIGATE - need a host to complete life cycle, primarily for reproductive purposes
Describe the life cycle of the obligate parasite: Entamoeba histolytica
- trophozoites multiply in mucosa crypts of large intestine
- amoebae from cysts which exit via faeces
- these are ingested and form associations with gut wall and cause ulcers
Pros and Cons of being ECTOparasitic
PRO: - dispersal/ less attached to host immune system
CON: - can be dislodged and exposed
Pros and Cons of being ENDOparasitic
PRO: - ease of feeding
- protection from predators
CON: - dispersal difficult/ vulnerable to immune system
What is a parasitoid?
Super vs Hyper
- animal that feeds in or on a living host, consuming all of most of tissues and eventually killing it
eg. wasps
Hyper: lays eggs in primary parasitoid larvae
Super: lays eggs in hyper parasitoid larvae
What is brood parasitism?
- social parasitism among birds
- egg laying in other species nests
