Diagnostic Laboratory Procedures

Agriculture, Food, and Natural Resource Standards Addressed AS.07.01. Design programs to prevent animal diseases, parasites and other disorders and ensure animal welfare. AS.07.01.01.b. Describe and demonstrate the proper use and function of specific tools and technology related to animal health management.

Microscope Use Objective lenses 4x, 10x, and 40x Oil-immersion is used occasionally A mechanical stage is necessary to view slides thoroughly

Microscope Use Viewing area = field

Microscope Use To scan a slide use 4x to focus, then move to 10x Scan back and forth overlapping each field

Microscope Use Scanning pattern

Microscope Use Debris can be closely examined under high power

Sample Collection The animal owner will most often collect the stool sample.

Sample Collection The sample should be fresh since some parasite eggs become unrecognizable as the feces ages.

Sample Collection If a fresh sample cannot be obtained, one can be refrigerated, but for no longer than 24 hours.

Methods Gross exam - used to observe outward characteristics of the sample.

Methods Gross exam - Several abnormalities can be seen with the naked eye.

Methods Gross exam - observe and record • color and consistency • blood and mucus • age of sample • presence of adult parasites

Methods - the fastest and simplest method of diagnosing parasitism. 2. Direct smear - the fastest and simplest method of diagnosing parasitism.

Methods 2. Direct smear - A small amount of feces is mixed with water and applied directly to a slide.

Methods 2. Direct smear - The main disadvantage of this technique is that a small sample may not contain any parasite eggs.

Methods 2. Direct smear - This method also leaves debris on the slide.

Methods 3. Floatation - the most commonly used procedure for diagnosing parasitism.

Methods 3. Floatation - techniques using this method: - simple floatation - use of a centrifuge - Fecalyzer

Methods 3. Floatation Fecalyzer - uses a solution (zinc sulfate or sodium nitrate) that has a specific gravity greater than the specific gravity of most parasite eggs

Methods - is commonly used for eggs that have a high specific gravity 4. Sedimentation - is commonly used for eggs that have a high specific gravity

Methods 4. Sedimentation - The high specific gravity of these eggs makes it difficult to use floatation techniques without distorting them.

Methods - Sedimentation allows eggs to sink to the bottom.

Debris may be easily confused with parasite eggs.

Common Debris: hair plant material air bubbles fat epithelial cells pollen grains