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Veterinarian Only Information Sheets

Giardiasis
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Disease name:

Giardiasis

Agent:

 Giardia duodenalis (syn. G. intestinalis, G. lamblia)

Infective forms:

Exists as intestinal trophozoite form and as an infective cyst.

Susceptible domestic species:

 Cats, dogs, and most domestic species

Zoonotic?:

 No

Diagnostic tests:
Direct smear
Zinc flotation with centrifugation
Flotation without centrifugation
Idexx ELISA SNAP test

Test sensitivity (likelihood test will correctly ID truly infected animals)
~ 50% on diarrheic feces
~75% on 3 samples over 5 days
Poor (probably <10%)
85-90%

Test specificity (likelihood test will correctly ID those NOT infected)
Must distinguish from T. foetus in cats
Good, if able to distinguish from coccidia, yeast etc.
95-99%

Test comments:
Must be fresh sample
Cyst shedding is intermittent – must sample repeatedly
Test is essentially not recommended for giardia
Can test + for up to 2 weeks following successful treatment

Other tests:

There are several other tests available from laboratories. The ProspectT microplate ELISA and FA tests are good; please call your lab for details on the tests and on their specificities/sensitivities. (The ProspectT RAPID assay is less sensitive).

Prevalence in shelters:

 Cats: 10-30% (up to 100% in some catteries)
Dogs: 20-40% (up to 100% in some kennels)

Vaccine available?:

 Yes, however it is not recommended as it has not been proven to be effective.

Excreted in:

 feces

Mode of transmission:

 Fecal-oral either directly or indirectly via e.g. fecal contaminated water or food.

Disinfection:

 Cysts can exist for months in a moist/cool environment. Quaternary ammonium-containing disinfectants are effective at room temperature. Drying of kennels also helps in between disinfection.

Incubation:

Average prepatent period is 8 days in dogs, 10 days in cats. Onset of disease (if it occurs) may precede cyst shedding by 1-2 days.

Post-recovery shedding:

Shedding may still occur even after disease is treated. It is advisable to retest animal at the end of treatment and then again several weeks later.

Carrier state?:

 YES. Most infections in otherwise healthy adult animals are asymptomatic. Self cure is possible as is chronic shedding.

Treatment and prevention of outbreaks:

Fenbendazole (panacur) 50mg/kg q 24 hrs x 5 days

Febental/pyrantel/praziquantel (Drontal Plus) 56.5mg febentel /cat q 24 hrs x 5 days.

Metronidazole 20mg/kg q 12 hrs x 5-7 days (less effective and resistance is possible).

Reinfection is common so decontamination of the environment in shelters is paramount. Bathing can also help decrease cyst load found on fur.

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