Giardiasis

Introduction. 

Giardiasis, also known as beaver fever because of its wilderness prevalence and animal reservoir (zoonotic), is an intestinal infection caused by the flagellated protozoan Giardia lamblia. Only 10 - 25 cysts are sufficient to cause infection. Giardia cysts are resistant to chlorination. Symptoms include foul-smelling diarrhea.

Summary

• Cause: Giardia lamblia
• Microscopy: Flagellated protozoan, sucking disk for attachment, "2 eyes" 
• Transmission: Contaminated water (wilderness); animal reservoir (zoonotic)
• Life cycle
• Symptoms: foul-smelling diarrhea, cramps, flatulence, fatty stools
• Complications: Severe malabsorption disease
• Pathogenesis: Cysts hatch after passage through stomach; trophozoites have sucking disks to attach to intestinal lining, resulting in malabsorption of nutrients
• Treatment: Quinacrine or metronidazole