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Diarrhea In Dogs And Cats |
D405
- Giardia spp. |
| Description:
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Giardia
is a protozoan parasite found in the intestinal tract
of human beings and most domestic animals throughout
the world. It has two morphologic forms; the trophozoite
form, which is motile and dwells in the intestinal lumen;
the cyst form, which contains two incompletely separated
but formed trophozoites, and is responsible for transmission
and environmental survival. The life cycle of Giardia
is direct. After ingestion, cysts (trophozoites are
noninfective) excyst in the duodenum, following exposure
to gastric acids and pancreatic enzymes, and the two
released trophozoites separate, mature, and attach to
the brush border of the villous epithelium. In dogs,
the organism seems to prefer the duodenum and jejunum
but has been isolated from the ileum to the duodenum.
In cats, trophozoites have been found throughout the
intestinal tract. Trophozoites may be passed in diarrheic
stools, but cysts are more routinely shed. The cysts
can survive for days or weeks in cool, moist conditions
while trophozoites cannot survive long outside the host.
The prepatent period of Giardia infection ranges from
5 to 12 days in dogs and from 5 to 16 days in cats.
The onset of disease, when it occurs, may precede cyst
shedding by 1 to 2 days. Putative differences in virulence
of Giardia strains, as well as host genetics and immune
status, usually determine the outcome of an infection.
Most infections (where cysts are being passed in the
feces) are nonsymptomatic. Acute diarrhea tends to occur
in very young puppies and kittens shortly after infection.
In older cats and dogs, diarrhea may be acute and short
lived, intermittent, or chronic. Feces are often malodorous,
pale, and steatorrheic. Affected animals may experience
weight loss secondary to diarrhea, but rarely will they
become inappetent. Studies have shown that birds are
also susceptible to Giardia infection. Infected birds
shed cysts and noninfective trophozoites in feces. Birds
with clinical signs including chronic to intermittent
diarrhea with loose, malodorous, mucoid stools; lethargy;
anorexia; dry skin; and feather plucking should be screened
for Giardia infection.
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| Diagnosis:
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Often,
Giardia infection goes undetected, even when the presence
of Giardia is high in the animal. Reasons for this occurrence
may include failure to consider it in the differential
diagnosis, failure to recognize the organisms, use of
inappropriate methods for fecal analysis, and intermittent
excretion of organisms in feces of infected individuals.
Commercial ELISA kits to detect fecal Giardia antigens
in humans are available, but these kits have shown reduced
sensitivity and specificity for detection of Giardia
in dogs. Also, ELISA kits are somewhat difficult to
perform and fairly expensive. A PCR-based assay is now
available for the detection of Giardia in a fecal sample.
This assay allows for high specificity and sensitivity
of detection. Since PCR detects the presence of Giardia’s
genetic material, only a few organisms need to be present
in a sample, making detection very accurate and definitive.
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| Treatment: |
No
drug to treat giardiasis in small animals has been officially
approved. Fenbendazole (Panacur graniles 22.2%, Hoechst-Roussel
Agri-Vet Co, Somerville, NJ) at the dose approved for
dogs (50 mg/kg) for the control and removal of roundworms,
hookworms, and whipworms, and the tapeworm Taenia pisiformis,
has been shown effective in removing Giardia cysts from
the feces of dogs. The medication should be administered
over 3 days at 24 intervals (Greene C. – Infectious
diseases of the dog and cat. 1998). |
| Sample:
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1.
Feces in a sterile container |
| Special
Handling: |
Store
samples at 4°C until pick up or shipment. |
| Test
Code: |
D405 |
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dog diarrhea a dog diarrhea d dog diarrhea
