Parasitology Lab

1
Parasitology Lab

• AnS 224, Spring 2009

2
Bloody Feces

• What tests should be run?
• Fecal float
• Fecal cytology (Fix and Stain, dead
• Direct fecal smear (Fresh, alive)
• Fecal antigen tests (more sensitive, more
  expensive than float)

3
Antigens

• Any molecule that sometimes stimulates an immune
  response
• Usually proteins or polysaccharides
• Test for by using antibodies (in blood)

http//www.poultry-health.com/library/serodiss/eli
sa13.jpg
4
Blood

• Composed of plasma and cellular components
• Plasma - liquid portion of blood
• Serum - blood plasma with clotting factors
  removed
• Serology

5
Cytology

• Make thin layer of feces on glass slide with
  saline
• Want bacteria to be completely separate
• Heat fixation
• Can use lighter
• Aid in fixing sample to slide
• Aid in uptake of stain

6
Cytology - Diff Quick

• Alcohol
• Basophilic stain (high pH - blue portion)
• Eosinophilic stain
• Use high magnification - oil for 100x

7
Clostridial Enteritis

• Diarrhea
• Stains at one end

8
Spore Forming Bacteria
http//srs.dl.ac.uk/Annual_Reports/AnRep01_02/anth
rax-bacteria.jpg

• Anthrax
• Botulism

Anthrax
http//www.foodhaccp.com/memberonly/0829.jpg
9
Sporulation

• Happy dog diarrhea (unlike parvo)
• Treat with antibiotics

10
Campylobacter

• 1-2 in microscope is normal
• 5-10 indicates disease

11
Direct Fecal Smear

• Thicker than cytology
• Smear on slide, add water or saline, and use
  coverslip
• Giardia
• Coccidia

http//www.infectiousdiseasenews.com/200709/eistor
ies2.jpg
12
Fecal Float

• Feces in tube and mixed with solution
• Place coverslip on top
• Solution needs to be more dense than eggs
• Saline - isotonic, not dense enough
• Zinc sulfate - good, dense salt solution
• Will effectively float organisms
• Take coverslip off and put on slide

13
Centrifuged Float

• Similar to fecal float but centrifuged
• More accurate
• Can be used efficiently with a lower number of
  eggs

http//www.windyhollowvet.com/images/roundworm.gif
http//pethealth.petwellbeing.com/w/images/3/3e/Do
g_Whipworm_egg.JPG
14
Antibody

• Most look like Y
• Binds to antigen on one of two arms that are
  specific to antigen
• Can have protein conjugate
• Enzymes bind substrates
• Horseradish peroxidase
• Colorometric technique

15
Antigen Tests

• Antigens detected by antibody based technique
• Use commercial antibody
• ELISA test
• Possible organisms to identify
• Giardia
• Parvovirus

16
Parasites

• Lab today will be examining fecal slides and
  identifying which parasites are present
• See handout for pictures you can use to help you.
• Complete worksheet and give to TA before leaving