The parasite is spread via the feces of an infected person or animal. Acquisition occurs when cysts are ingested via contaminated water or food, or via person-to-person contact. After excystation, trophozoites colonize and multiply in the small bowel and may disrupt epithelial brush border, mucosally invade, or elaborate an enterotoxin. The incubation is usually 7-14 days, with symptoms often lasting more than 2-4 weeks; however, patients may continue to shed cysts for 6 months or longer.
- Prolonged diarrhea – more than 7-10 days
- Foul-smelling, greasy stools
- Sulfuric belching
- Abdominal cramps
- Weight loss
- Travel to endemic regions
- Children in daycare
- Men who have sex with men
A07.1 – Giardiasis [lambliasis]
58265007 – Giardiasis
- Viruses – Usually shorter duration.
- Amebiasis – Patient has traveled to endemic region.
- Dysentery – Presence of blood and WBCs in stool.
- Noninvasive bacteria (eg, staphylococcal food poisoning, Clostridium perfringens food poisoning) – Usually shorter duration, possibly extra-intestinal manifestations.
- Cryptosporidium spp – Public swimming pools.
- Tropical sprue – Patient has lived more than 1 month in tropical region.
- Celiac disease – Gluten relationship.
- AIDS – With or without intestinal opportunistic infections.
- Inflammatory bowel disease (ulcerative colitis, Crohn disease) – Abdominal pain and alternating diarrhea and constipation.
- Neoplasm – Weight loss and fecal occult blood test positive.
- Other malabsorption syndromes – Risk factor and temporal relationship.
- Clostridioides difficile – Previous antibiotic exposure.