Giardia intestinalis (1) Flashcards
What is the common name?
Beaver fever
What are the hosts?
Domestic and wild animals
Humans
How do you identify cysts?
12 mm long
Ovoid
4 nuclei
Seen in feces
How do you identify trophozoites?
21 micro m long
Teardrop
2 nuclei
8 flagella with face-like appearance
Seen in fresh fecal smears
- Diarrhea
Explain the life cycle
Cyst ingested
Trophozoites in duodenum
Trophozoites adhere to microvilli (small intestine)
Multiply asexually (binary fission)/budding
Trophozoites encyst
Cysts pass down small intestine, passed in feces
- Infective form
Feces not well formed
Trophozoites may also be present in feces
Not able to survive long outside host
Cysts survive for 2-4 weeks
PPP: 1-2 weeks
What is the site of infestation?
Small intestine
Describe the Pathogenesis
Attach to microvilli of proximal small bowel to feed, occasionally cause duodenal ulcerations
Malabsorption common
Trophozoites cause acute fecal inflammation
Asymptomatic
Acute or chronic diarrhea
How do you diagnose?
Fecal smear demonstrates cysts and trophozoites (if feces are unformed)
Fresh fecal smears - detect trophozoites
Double centrifugation fecal flotation
- With zinc sulfate and stained with Lugol's iodine - Effective for detecting cysts in feces
ELISA tests for antigens - frequently used in dogs
PCR to determine assemblage
- Assist in addressing concerns regarding zoonosis
How do you treat?
No treatment approved in US
Fenbendazole approved in Europe for dogs
- Effective in dogs and cats
Metronidazole (treat human infections) effective in dogs and cats
Febantel, pyrantel pamoate, praziquantel - effective in dogs
Cattle:
- Several remedies approved - Benzimidazole in cattle - Calves: Fenbendazole/Albendazole as well as dimetridazole
Treatment can be for 5-15 days
How do you prevent?
Prevent fecal contamination of water/feed important
Sanitation/disinfection of environment
Reinfection from cysts can rapidly occur
Water filters with 10 micro m diameter prevent transmission
- Most household filters are 4 micro m
What is important about Giardia intestinalis?
It is ZOONOTIC
