Method for detecting circulating Toxocara canis antigen and its application in human serum samples.

Area of Science:

• Veterinary Parasitology
• Immunodiagnostics
• Molecular Biology

Background:

• Current immunodiagnostic methods for larval migrans (LM) detect antibodies, not active infections.
• Distinguishing active toxocariasis from past exposure is crucial for effective patient management.

Purpose of the Study:

• To develop a sensitive and specific sandwich ELISA for detecting circulating Toxocara canis antigen.
• To establish a diagnostic tool for identifying active toxocariasis infections.

Main Methods:

• Production of monoclonal antibodies (MAb) against excretory-secretory (ES) antigen of T. canis.
• Development of a sandwich ELISA using a selected MAb (TCMAb12).
• Testing ELISA specificity against various parasite antigens and sensitivity using a standard curve.

Main Results:

• The developed sandwich ELISA demonstrated high specificity for T. canis antigens.
• The assay achieved a detection limit of 5 ng/ml, indicating sufficient sensitivity for toxocariasis diagnosis.
• In suspected toxocariasis patients, 5 out of 9 serum samples tested positive for circulating antigen, suggesting active infection.

Conclusions:

• The sandwich ELISA is a sensitive and specific method for detecting circulating T. canis antigen.
• This assay can differentiate active toxocariasis from antibody-positive cases without active infection.
• The diagnostic tool aids in understanding the prevalence and active status of toxocariasis.