Giardiasis is an infectious disease caused by the flagellated microorganisms Giardia lamblia, affecting the duodenum and jejunum. Giardiasis is detected in 10% of the adult population and in 65% of children, which is associated with non-compliance with sanitary and epidemiological rules.
When entering the human body, Giardia begin to actively proliferate and affect the duodenum and small intestine, leading to a violation of their function - peristalsis, absorption, and wall digestion. Diarrhea develops. Further, the biliary tract and gallbladder, as well as the pancreas, may be involved in the process with the development of inflammation of these organs.
The "gold standard" of diagnosis is the detection of giardia by microscopy in feces and bile obtained by duodenal probing (bile sampling with a special instrument through the mouth opening, bypassing the esophagus and stomach). However, the parasite is not always excreted with feces, which makes it necessary to repeatedly repeat the test. In addition, it can only be detected in "fresh," warm feces.
In recent years, a more convenient and less painful method of diagnosing giardiasis has been successfully used by detecting specific antibodies to giardiasis. Test IgG determination to Giardia lamblia refers to the serologic diagnosis of infectious diseases. The test material is blood, in which antibodies to the pathogen are detected. Antibodies are components of the body's immune system that are produced to destroy a particular foreign protein-antigen. In this case, the antigen is giardia.
There are several types of antibodies: IgA, IgD, IgE, IgG, and IgM. However, the immune system cannot always cope with giardiasis, even with very high concentrations of antibodies. Each of these antibodies has its own function and its own period of occurrence. IgG antibodies are detected 20 days after infection, their high concentration persists at almost all stages of the disease. After recovery, the level of antibodies decreases within 1-2 months but completely disappears after 6 months.