A coproantigen diagnostic test for Strongyloides infection

Area of Science:

• Infectious Diseases
• Parasitology
• Immunodiagnostics

Background:

• Accurate diagnosis of Strongyloides stercoralis infection is difficult due to low larval concentrations in stool samples.
• Current diagnostic methods, including stool microscopy and agar plate culture, often require repeated sampling and lack sufficient sensitivity.

Purpose of the Study:

• To develop and evaluate a novel coproantigen-based enzyme-linked immunosorbent assay (ELISA) for the sensitive diagnosis of Strongyloides stercoralis infection.
• To assess the specificity of the developed ELISA against other parasitic infections and the stability of detected coproantigens.

Main Methods:

• Development of a polyclonal rabbit antiserum against Strongyloides ratti excretory/secretory (E/S) antigens.
• Establishment of an antigen capture ELISA utilizing the developed antiserum to detect Strongyloides coproantigens in fecal samples.
• Testing for cross-reactivity with antigens from Schistosoma japonicum, hookworms (Ancylostoma spp.), Trichuris muris, and S. mansoni.

Main Results:

• The developed coproantigen ELISA successfully detected infections with both rodent S. ratti and human S. stercoralis.
• The assay demonstrated high specificity, with no cross-reactivity observed against Schistosoma japonicum, Ancylostoma spp., Trichuris muris, or S. mansoni.
• Strongyloides coproantigens were found to be stable when frozen fecal supernatants were stored at -20°C for up to 270 days, but not at 4°C.

Conclusions:

• The development of a Strongyloides coproantigen ELISA presents a viable and potentially more sensitive diagnostic tool for human strongyloidiasis.
• This antigen detection method overcomes limitations of traditional parasitological diagnosis by identifying infection even with low larval burdens.
• Further development of this ELISA holds promise for improving the diagnosis and management of strongyloidiasis worldwide.