Monday, August 6, 2012

Alpaca Fecal Testing with Centrifuge

We recently began to test our own samples instead of running them to the lab.  It is easy to do once you are set up.  It takes a little time, but once you get it, you will save money and potentially time from the lab.  It is crucial that a sugar floatation is used because of the type of worms alpacas can carry.

What you need:
  • Fixed head centrifuge with speeds up to 2500 rpms (bought ours online for $100)
  • Microscope (varying from 10x to 40x)
  • 15 ml tubes
  • Slides and cover slips
  • Cups
  • Latex Gloves
  • Gram Scale
  • Metal Strainer
Sugar Recipe
  1000 mL (4 Cup + 3 Tbls) Tap water             
  1170 g (6 ¼ Cup) Sugar                                 .
                

 Heat the sugar and water on low until clear and all the sugar is in solution, then add the Formaldehyde.  Best to keep in refrigerator until use.
  1. Obtain a fecal sample of at least 5 grams.  If you can only get a few grams worth, that will still work.  Either pick up fresh pellets from the ground without contamination, or catch the alpaca and pull a sample from the rectum using lubricant jelly and a latex glove.  When we pull our samples, we just turn the glove inside out to store the feces until you are ready to process. Keep in the refrigerator.
  2. Using a gram scale, weigh 5 grams of feces in a specimen container
  3. Add 95 mL of tap water (note: if you do not have 5 grams, see table below)
  4. Let feces sit in specimen container for 1 – 2 hours and then smash up feces until pellet is completely disintegrated (can pre-smash in glove before put in water to help with this step then smash again). Store covered specimen container in refrigerator overnight (can leave in for up to 5 to 7 days).
  5. Swirl mixture in specimen container to re-mix the feces, avoid making bubbles.  Pour the mixture through a fine metal strainer (or tea strainer) into another container with a pouring spout.
  6. Immediately pour 10 mL of fecal solution into a tapered centrifuge tube.  Centrifuge the sample for 7 minutes at speed 4 (out of 10)
  7. Pour off the supernatant (water) and fill half the tube with sugar solution (see recipe) and mix in the fecal pellet at the bottom of the tube thoroughly – using a plastic stir stick.  Wood can absorb bacteria, so we suggest plastic.
  8.  Fill the rest of the tube with sugar solution until a small bulge forms just above the top of the tube and place a coverslip on top of the tube.
  9.  Let sit for at least 120 minutes and then carefully remove coverslip and place on slide
  10.  Count ALL the Strongyle-type eggs (count Nematodirus separate), Eimeria macusaniensis (E. mac-Large coccidia), small and medium coccidia, Tapeworms, Whip worms, Capillaria, etc, separately
  11. Multiple each count by 2,   Specific gravity 1.27

Equivalence Table
Feces (grams)
Water (mL)
Multiply
5
95
2
4
76
2
3
57
2
2
38
2
1
19
2


HINTS
1.         If you have a negative sample, and are highly suspicious of a parasite problem, let the feces sit for several days in the fridge before testing again.  The soaking stage allows the eggs to be liberated from the hay in the feces and more eggs to find on the slide.
2.         If you have a negative sample and are highly suspicious of E. mac, repeat Step 5 and 6, after you decant the supernatant look at a sample of the fecal pellet at bottom of tube as a direct smear.

Common oocycts found in alpacas.










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