An enzyme immunoassay for the qualitative and semiquantitative determination of IgG-class antibodies to Echinococcus in serum and plasma.
Echinococci are microscopic cestodes (tapeworms) with a length of 1.4 to 6 mm which are dependent on their genus found.
o either in dogs or other canids (E. granulosus)
o or in foxes, coyotes and wolves (E. multilocularis)
Sources of infection are final hosts (i.e. dogs for E. granulosus and mainly foxes for E. multilocularis) and food contaminated with parasite eggs. After ingestion of a suitable intermediate host, the egg hatches in the small bowel and releases an oncosphere that penetrates the intestinal wall and through the circulatory system into various organs where it develops into a cyst. Echinococcus infections remain silent for years before the enlarging cysts cause symptoms in the affected organs E. granulosus larvae (oncospheres) begin to vesiculate mainly in the liver but also in the lungs and in other organs (20%). The parasites form spherical, unilocular, fluid-filled cysts and can achieve diameters between 1-15 cm.
In contrast to cystic echinococcosis, E. multilocularis larvae are found almost exclusively (98%) in the liver, but secondary lesions can spread metastatically to other organs (lungs, kidneys, CNS and others). The parasites grow infiltrative and tumor-like in the host tissue. E. granulosus occurs practically worldwide E. multilocularis occurs in the northern hemisphere, including central Europe and the northern parts of Europe, Asia, and North America. Detectable immune responses have been associated with the location, integrity, and vitality of the larval cyst. Cysts in the liver are more likely to elicit antibody response than cysts in the lungs, and regardless of localization, antibody detection tests are least sensitive in patients with intact hyaline cysts. Cysts in the lungs, brain, and spleen are associated with lowered serodiagnostic reactivity whereas those in bone appear to more regularly stimulate detectable antibody. Fissuration or rupture of a cyst is followed by an abrupt stimulation of antibodies. A Differentiation between both species of Echinococcus is not possible.
The DRG Echinococcus IgG ELISA Kit is a solid phase enzyme-linked immunosorbent assay (ELISA) Microtiter wells as a solid phase are coated with Echinococcus antigen. Diluted patient specimens and ready-for-use controls are pipetted into these wells. During incubation Echinococcus-specific antibodies of positive specimens and controls are bound to the immobilized antigens. After a washing step to remove unbound sample and control material horseradish peroxidase conjugated anti-human IgG antibodies are dispensed into the wells. During a second incubation this anti-IgG conjugate binds specifically to IgG antibodies resulting in the formation of enzyme-linked immune complexes. After a second washing step to remove unbound conjugate the immune complexes formed (in case of positive results) are detected by incubation with TMB substrate and development of a blue color. The blue color turns into yellow by stopping the enzymatic indicator reaction with sulfuric acid. The intensity of this color is directly proportional to the amount of Echinococcus-specific IgG antibody in the patient specimen. Absorbance at 450 nm is read using an ELISA microtiter plate reader.