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Low avidity IgG antibodies in diagnosis of recent human schistosomiasis
Nahed E Mostafa1, Adel Awad, Mohsen Shalaby
1Department of Parasitology, Faculties of Medicine, Zagazig, El-Menia, Egypt.
Insights
This study highlights low avidity IgG as a valuable diagnostic marker for recent schistosomiasis infections in children. Early detection through this method aids in timely intervention for schistosomiasis.
Area of Science:
- Infectious Diseases
- Parasitology
- Immunodiagnostics
Background:
- Schistosomiasis remains a significant public health concern in endemic regions like Sharkia Governorate.
- Accurate diagnosis, especially for recent infections, is crucial for effective control programs.
Purpose of the Study:
- To evaluate the utility of low avidity IgG in diagnosing recent schistosomiasis infections.
- To compare diagnostic performance of ELISA (IgG & IgM), circulating antigens, and low avidity IgG.
Main Methods:
- Parasitological screening and follow-up of 130 school children.
- Serological testing using ELISA for IgG and IgM antibodies.
- Assessment of IgG avidity and detection of circulating antigens.
Main Results:
- ELISA detected IgM in all cases and IgG/circulating antigens in 90% of patients.
- Low avidity IgG was identified in 85.71% of recently infected children.
- High specificity (>99%) was observed for ELISA; IgM/IgG ratio >1 indicated recent infection.
Conclusions:
- Low avidity IgG is a promising and valuable biomarker for diagnosing recent human schistosomiasis.
- Combining IgM/IgG ratio and IgG avidity enhances the diagnosis of early-stage schistosomiasis.
Abstract:
One hundred thirty school children from a schistosomiasis endemic area in Sharkia Governorate, were selected on parasitological findings. Seventy persons were negative on the first screen and turned positive after 3 months of the screening (recently infected). Stool examination, ELISA (IgG & IgM), low avid IgG, and circulating antigens were performed for all patients and controls. ELISA detected IgM in all cases. IgG and circulating antigens in 90% of schistosomiasis patients. Low avidity IgG were detected in 85.71% of recent cases. The specificity of ELISA appeared to be >99%. The IgM/IgG ratio was >1 in patients with recent infection. The percentage of fall of O.D. readings of IgG after addition of 6 molar urea was high among cases with recent infection. Low avid lgG appears to be good and valuable in diagnosis of recent schistosomiasis in man.
