Giardia lamblia
(gee-are-dee-a / lam-blee-a)
Trophozoite
Cyst
Transmission
This parasite is transmitted by water sources such as ponds, lakes and streams that has been contaminated by cyst containing feces. Contaminated fruits and vegetables can also transmit it. Occasionally, oral-anal sex can transmit G. lamblia. Once cysts are ingested, excystation occurs in the duodenum of the small intestine, where multiplication occurs in eight hour intervals. The trophozoite will attach to the intestinal mucosa by means of its sucking disk.
Disease
Giardiasis
- This is the most pathogenic intestinal flagellate.
- Incubation lasts 2-3 weeks.
- Symptoms include:
- watery foul-smelling diarrhea, abdominal cramps, flatulence, anorexia, nausea
- vitamin deficiencies, folic acid deficiencies, hypoproteinemia
- in severe cases, weight loss and malabsorption syndrome may occur
- Often, patients are asymptomatic.
Diagnostic
- Laboratory specimens
- stool
- in watery stool, you will find trophozoites
- in formed stool, you will find cysts
- duodenal aspirates (trophozoites and cysts)
- stool
- Testing
- wet mount
- permanent smears made with trichrome or iron hematoxylin stain
- Serological test
- antigen detection
- immunofluorescence
- enzyme immunoassays
Treatment
Metronidazole is the treatment of choice. Alternate choices include quinacrine, tinidazole, furazolidone and paromomycin.