Giardia lamblia ELISA

Giardia lamblia is the protozoan parasite responsible for the disease giardiasis. Symptoms of acute giardiasis include diarrhea, nausea, weight loss, malabsorption, abdominal cramps, flatulence and anemia. The disease may manifest itself as an acute, chronic or as an asymptomatic infection. Giardiasis is the most prevalent parasitic disease in the United States and is responsible for an estimated 100 million mild infections and 1 million severe infections each year. The mode of transmission of Giardia is through faecal-oral ingestion of cysts. Epidemics of giardiasis have been documented in day care centres and by drinking contaminated water. Day care centres may be directly or indirectly responsible for 45 % of diagnosed Giardia infections in the United States. One study found 54 % of the children at a day care centre were infected. Another important source of Giardia infection is among homosexual men. Prevalence rates of 5 to 19 % for this population have been reported. Diagnosis of giardiasis has been done through a number of invasive and non-invasive techniques. Of the non-invasive techniques, microscopic examination of stools has been the most common. However, this method relies on an experienced technician and subsequent observation of intact organisms. Because of the historically low proficiency of correct microscopic examinations and intermittent excretion of organisms, alternative diagnostic methods have been investigated. One important alternative has been the development of an antigen capture enzyme linked immunosorbent assay (ELISA) for use with stools. These tests have shown comparable sensitivity to experienced microscopic examinations, are fairly simple to perform and do not require the observation of intact organisms.