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.
However the disease may manifest with no discernible symptoms. 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 annually.
The mode of transmission of Giardia is through fecal to oral ingestion of cysts. Epidemics of Giardiasis have
been documented in day care centers and by drinking contaminated water. The parasite is protected by an
outer shell, therefore it can survive outside the body and in the environment for long periods of time.
Giardia is found in soil, food, water, or surfaces that have been contaminated with feces from infected
humans or animals. A person can become infected after accidentally swallowing the parasite; but cannot
become infected through contact with blood. You can become infected with Giardia lamblia if you swallow
contaminated recreational water. Recreational water such as in swimming pools, hot tubs, jacuzzis,
fountains, lakes, rivers, springs, ponds, or streams that can be contaminated with sewage or feces from
humans or animals.
Day care centers may be directly or indirectly responsible for 45% of diagnosed Giardia infections in the
United States! One study found that 54% of children at a day care center were infected. Another important
source of Giardia infection is among homosexual men. 5%-9% rates of infection for this population have
Giardiasis diagnosis has been done through a number of invasive and non-invasive techiniques. Of the
non-invasive type, detection using microscopic examination of stools is the most common. The drawback to
this method is that it requires an experienced technician and subsequent observation of intact organisms.
Historically, there has been a low proficiency of correct microscopic examinations, and due to the
intermittent excretion of intact organisms, alternative diagnostic methods have been developed.
One important alternative to microscopic examination has been the development of IVD Research's ELISA
(enzyme linked immunoabsorbent assay) tests for use with stools. The sensitivity of these tests are
comparable to experienced microscopic examinations, are fairly simple to perform and do not require the
observation of intact organisms. IVD Research's Giardia Antigen detection ELISA has been FDA approved
and is being used worldwide.