Diagnostic techniques Flashcards
Fecal samples are appropriate in which parasites?
Parasites of digestive system
If you suspect a person’s animal has intestinal parasites, what steps would you instruct them to take to get a good faecal sample to a lab for testing…?
fresh faeces in sealed, marked container (if not possible - refrigerate)
describe condition of stool (colour, consistency, blood, etc)
For large animals should be collected directly from animal’s rec9/t1u5m/20
Exam for parasites in fecal sample (direct smear)…
pros: quick procedure time, minimal equipment, can observe eggs & larvae
cons: not good representative (small sample size), could be innacurate
Exam for parasites in fecal dog sample (faecal flotation)…
Add a small amount of faeces (1 g) to fecalizer
Add 1-2 ml saturated sodium nitrate
Mix well with tooth pick until smooth
Insert the green mesh, push it down until click
Fill fecalizer with sodium nitrate right up to the top until small meniscus appears Put the cover slip gently on top of the meniscus
Leave 10 minutes
Remove the cover slip by lifting up and put it on slide
Look at it with 10 times magnifications. Use the picture provided to identify the eggs.
Exam for RUMINANT AND EQUINE FAECAL EGG COUNT…
Add faeces to salt solution -> measuring cylinder to 60mL with salt solution & agitate until homogenous. Working quickly, place the sieve tube into the cylinder. Pipette around 0.5ml from the middle of the sieve tube and expel any air from the tip.hold the pipette at around 45° and touch the tip against the side of the chamber and fill by gently squeezing the bulb
Exam for parasites in fecal sample (when would you use sedimentation test)?
for fluke eggs as they are denser & larger
What kind of stool are ideal for cysts/trophozoites?
cysts: formed
trophozoites: watery
Sample collection at necropsy…?
Fish & fox pracs
An important method for diagnosing parasitism
Lesions of internal organs
Worms should be washed and placed in 70% ethanol
Flukes and tapeworms should be kept in warm water (37oC for few hours then in 70% ethanol
Allergic reaction
Labeling
How to transfer parasite materials to a lab?
Depends on the size and type of the parasite, or tissue:
Ethanol 70% vs Formalin (for most worms and big parasites)
Sticker tape (for eggs or small motile insects)
Freezing
Send the infected tissue for histopathology (e.g., intracellular parasites, worms’ cysts)
Remember:
Good labelling Providing enough info
blood samples on slides for microscopy use…?
air drying -> methanol -> giemsa stain 30 mins -> wash water
Eaxamination of the urine samples
Mix urine Put 5- 10 ml in a centrifuge tube Centrifuge 5 min (1500 rpm) Remove the supernatant Mix the remaining and examine 1 drop under the microscope
Difference between Acarina (ticks and mites) & Insects (fleas, lice, flies and mosquitoes)?
acarina - 8 legs adults & 2 body parts
insects - 6 legs adults & 3 body parts
How to measure a parasite?
Ocular micrometer
Pro’s & con’s of light microscopy?
pros: simple, fast, cost effective, final confirmation
cons: limited magnification, resolution, ID’ing internal structures
Advantages of Scanning electron microscopy (SEM) over light microscopy…?
e’s rather than light
higher resolution
higher magnification
cons: extracellular parasites only
