Giardiasis: the definition of antibodies to lamblia antigens in the blood
Last reviewed: 23.04.2024
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Antibodies to Lamblia intestinalis antigens are not present in the serum normally.
The causative agent of giardiasis - Lamblia intestinalis ( Giardia lamblia ) is of the flagellate type. In the human body lamblia is found in the duodenum and jejunum in vegetative form and in the form of cyst. Giardiasis is universally met, lamblia reveals in 10-12% of practically healthy adults and in 50-80% of children. When lamblia gets into the human body, they multiply in large numbers and colonize the mucous membrane of the duodenum and jejunum, leading to disruption of peristalsis, parietal digestion and absorption. Developing bowel dysfunction (diarrhea, sometimes with an admixture of blood). The process may involve bile ducts and the gallbladder (cholangitis, cholecystitis), as well as the pancreas.
For the diagnosis of giardiasis, feces (detection of cysts and vegetative forms of the pathogen) and biliary, obtained with duodenal probing (the detection frequency of lamblia does not exceed 50%) are most often studied. In connection with the non-permanent allocation of a parasite with feces, it is necessary to conduct repeated analyzes. In recent years, test systems based on ELISA have been developed, which allow detecting the surface antigen of lamblia cysts in feces. The diagnostic sensitivity of the method is 90%, the specificity is 100%. To obtain a positive result of the analysis for giardiasis, it is enough to have 10-15 cysts of lamblia in the stool samples. In some cases, false positive results of the study are possible if other infectious agents of parasitic infections are present in the stool.
Recently for the diagnosis of giardiasis using the ELISA method, which allows to determine in the patient's blood the content of specific antibodies to lamblia antigens. Existing ELISA test systems can detect separately specific antibodies of different classes (IgM, IgA, IgG) or total antibodies. Antibodies of IgM class to lamblia antigens are found in the blood on the 10-14th day after the invasion. Then antibodies of class IgG appear and remain at a high enough level practically at all stages of a lambliasis. After complete elimination of the parasite, the level of specific (IgG) and total antibodies decreases sharply within 1-2 months. Antibodies disappear from the blood completely within 2-6 months.
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