Giardiasis
Giardiasis is an intestinal infection caused by Giardia parasites. It can cause diarrhea, abdominal cramps, nausea, and impaired nutrient absorption.
Giardia duodenalis: A protozoan species that infects the small intestine of humans and other mammals. This parasite, also called Giardia lamblia, is the main cause of human giardiasis.
Giardiasis diagnosis: The identification of Giardia infection using stool tests or, less commonly, samples from the small intestine. Because cyst shedding can be intermittent, diagnosis may require more than one stool sample.
Antonie van Leeuwenhoek: A Dutch microscopist who made pioneering observations of microorganisms in the seventeenth century. He described Giardia-like organisms in his own stool in 1681.
Malabsorption: Impaired digestion or absorption of nutrients across the intestinal lining. Giardia can disrupt small-intestinal function, contributing to greasy stools, weight loss, and nutrient deficiencies.
Cryptosporidiosis: An intestinal infection caused by Cryptosporidium parasites, often transmitted through contaminated water. It can resemble giardiasis clinically but is caused by a different protozoan and has distinct testing considerations.
Giardia life cycle: The cycle in which Giardia cysts are ingested, develop into trophozoites, and produce new cysts shed in feces. Its stages explain how infection begins and how Giardia spreads onward.
Stool antigen test: A test that detects Giardia proteins in a fecal sample. Antigen testing can identify infection without relying solely on finding intact parasites by microscopy.
Alfred Mathieu Giard: A French zoologist whose name is associated with the genus Giardia. The parasite’s genus commemorates Giard, though its naming history also involves Vilém Lambl.
Post-infectious irritable bowel syndrome: Irritable bowel syndrome that begins after an episode of gastrointestinal infection. Some people develop persistent bowel symptoms after the Giardia infection has cleared.
Amoebiasis: An infection caused by Entamoeba histolytica, which can produce intestinal disease and sometimes liver abscesses. It is another protozoal intestinal infection, but invasive disease and dysentery are more characteristic.