Parasitology Flashcards
What is hypobiosis/ALD (arrested larval development? and example
When larvae stop developing in host e.g trichostrongyle species like ostertagia.ostertagia
What factors can induce hypobiosis ?
-northern hemisphere -autumn - cold
-immune response to L3 worms
What cause larvae to come out of hypobiosis give an example ?
-overwintered eggs and larvae on pasture - due to environment changing
-peri-parturient rise - due to high prolactin immune competency low
Why is hypobiosis an immune evasion mechanism ?
larval parasites are encapsulated in tissue inaccessible to immune system
Immunosuppression mechanism
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examples immune evasion
hypobiosis
evading hosts immune response - undetected
neonatal immunological unresponsiveness
What are protozoa ?
-single-celled eukaryotic
-feed heterotrophically ( eat other things for energy )
-e.g parasites
Name important GI protozoa
coccidiosis
crytosporidiosis
toxoplasmosis
neosporosis
giardiasis
trichomoniasis
histomoniasis
balantidiasis
spironucleasis
What is a paratenic host ?
parasite doesn’t develop in it it becomes dormant
What is the baermanns technique and how do you do it ?
- technique to separate larvae from faecal material
-faeces suspended in warm water while larvae move into water and sink to the bottom and are collected for identification
-iodine staining
What is the mcmaster technique and how do you do it?
-quantitative
-count eggs based on floatation in salt solution
-weight 1g faecal sample
-add 20 ml flotation fluid whilst mix
-filter suspension through tea strainer using rest of flotation fluid ( 60 )
-fill two compartments of mcmaster slide with faecal filtrate
-leave stand - no more 5 min
number of eggs /g faeces =
volume of counted chamber x weight of faeces
Name and briefly describe other faecal analysis methods
-direct smear - on microscope slide
-faecal sedimentation - trematode eggs - will sink
-faecal flotation - floatation fluid - nematode / cestode will float
-larval culture - drug testing and identifying l3 larvae nematodes
