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Giardia Testing Globulins 1347

Giardia Testing
VetBooks.ir Definition Drug Effects

(RT-PCR) detects Giardia-specific amplified
Giardiasis is a diarrheal disease caused by the • Real-time polymerase chain reaction Administration of antiprotozoal drugs may
protozoan Giardia in animals and humans. DNA sequences on feces. decrease Giardia shedding.
Giardia duodenalis is the most common species
that affects dogs; however, there are numerous Reference Interval Lab Artifacts
assemblages with various infectivity for animals • Direct fecal smear: positive or no trophozoites On fecal flotation and direct fecal smear, yeast
and humans. Fecal-oral exposures via food, or cysts seen can appear similar in morphology and size to
water, or fomite transmission are common • Fecal flotation with centrifugation: positive Giardia cysts, but yeast lacks internal structures
routes of infection. or no cysts seen (i.e., median bodies and two to four nuclei)
• Giardia fecal ELISA: positive or negative and is often seen budding.
Synonym • Direct IFA: positive or no cysts seen
Beaver fever • RT-PCR: positive or below detectable limit Specimen Collection and Handling
Fresh unrefrigerated feces collected within 30
Physiology Causes of Abnormally High Levels minutes for direct smear. Fresh feces (within
Giardia cysts are ingested by the animal. Evidence of intestinal infection 24 hours) and stored between 2°C-8°C for all
Bile acids degrade the cyst wall in the small other Giardia testing.
intestine, resulting in the release of trophozoites Next Diagnostic Steps to Consider
that attach to the apices of small intestinal if Levels Are High Relative Cost: $ to $$
villi. Attachment leads to villus blunting and In symptomatic animals, initiation of antipro-
ultimately malabsorption and diarrhea. As tozoal therapy is recommended. See p. 386. Pearls
trophozoites move toward the colon, they • Giardia testing should be performed only
become encysted and pass in feces. Causes of Abnormally Low Levels on symptomatic animals.
• Direct fecal smears use a drop of saline with Intermittent shedding of the organism; concur- • Zinc sulfate is the preferred solution for fecal
a minuscule amount of diarrheic stool to rent or previous antiprotozoal administration; flotation. Sugar solutions tend to distort and
identify motile trophozoites using microscopy not infected collapse Giardia cysts.
visualization. Lugol’s iodine can be added to • Tritrichomonas sp. trophozoites in cats can
enhance visualization. Next Diagnostic Steps to Consider appear morphologically similar to Giardia sp.
• Zinc sulfate (ZnSO 4) fecal flotation relies if Levels Are Low trophozoites. Giardia sp. trophozoites have a
on accurate identification of cysts that have Repeat testing in symptomatic animals, possibly “falling leaf” motion versus the erratic move-
floated to the surface when feces have been using an alternative testing method. ments of Tritrichomonas. Trophozoites die
mixed with ZnSO 4 via simple or centrifugal within 30 minutes of defecation or collection.
methods. Important Interspecies Differences • Giardia sp. cysts are similar in size to a canine
• Giardia fecal ELISA detects the Giardia Dog strains are not known to infect cats. Cat RBC and easiest to visualize at 40x objective.
antigen in feces. strains are not known to infect dogs. Human
• Fecal direct immunofluorescence assay infection as the result of exposure to canine AUTHOR: Erin N. Burton, DVM, MS, DACVP Laboratory Tests
EDITOR: Lois Roth-Johnson, DVM, PhD, DACVP
uses Giardia-specific fluorescently labeled giardiasis is considered a rare occurrence.
antibodies to detect Giardia cysts in feces.

Globulins

Definition Causes of Abnormally High Levels hydration status adequate, interpret with
Globulins are all of the non-albumin proteins • Polyclonal gammopathy: any cause of chronic other lab work (e.g., CBC, chemistry panel)
found in blood. They can be further classi- inflammation, hepatic disease, feline infec- and physical exam to prioritize differentials.
fied as alpha, beta, or gamma via protein tious peritonitis, occult heartworm disease, • Protein electrophoresis and/or immunoelec-
electrophoresis. immune-mediated disease trophoresis to differentiate monoclonal from
• Monoclonal gammopathy: usually lymphoid polyclonal gammopathy
Physiology malignancy such as multiple myeloma,
Globulins are a heterogeneous group of serum lymphoma, or lymphoid leukemia. Rarely Causes of Abnormally Low Levels
proteins that include immunoglobulins, coagu- reported with non-neoplastic conditions • Primary/inherited and acquired immuno-
lation factors, complement, many acute-phase including canine ehrlichiosis, leishmaniasis, deficiencies, including failure of passive
proteins, and lipoproteins, with a wide variety lymphoplasmacytic enteritis and dermatitis transfer
of physiologic functions. • If concurrent hyperalbuminemia: dehydration • If concurrent hypoalbuminemia (panhypo-
proteinemia): consider hemorrhage, protein-
Reference Interval Next Diagnostic Steps to Consider losing enteropathy, exudative dermatopathy/
Dogs: 2-4 g/dL (20-40 g/L). Cats: 2.5-5 g/dL if Levels Are High burns, and severe malnutrition/starvation.
(25-50 g/L) • If hyperalbuminemia and supportive physical Albumin and globulin values are variable
exam findings, consider dehydration. If with liver disease.

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