Towards saliva-based screening for sleeping sickness?

Area of Science:

• Medical diagnostics
• Parasitology
• Immunology

Background:

• Sleeping sickness, also known as human African trypanosomiasis, is a vector-borne parasitic disease.
• Current diagnostic methods can be invasive and complex, limiting their use in field settings.
• There is a need for simple, non-invasive diagnostic tools for sleeping sickness.

Purpose of the Study:

• To investigate the feasibility of detecting trypanosome-specific antibodies in saliva for sleeping sickness diagnosis.
• To evaluate the efficacy of indirect enzyme-linked immunosorbent assay (ELISA) for saliva-based antibody detection.
• To compare saliva-based antibody detection with existing serological tests.

Main Methods:

• A pilot study involving 23 patients with confirmed Trypanosoma brucei gambiense sleeping sickness and 14 healthy controls.
• Indirect enzyme-linked immunosorbent assay (ELISA) was used to detect trypanosome-specific antibodies in saliva samples.
• Agglutination tests (CATT/T. b. gambiense and LATEX/T. b. gambiense) were also performed on saliva samples.

Main Results:

• All 23 sleeping sickness patient saliva samples tested positive by indirect ELISA, while all 14 control samples were negative.
• Antibody levels in saliva correlated with serum levels but were approximately 250-fold lower.
• Agglutination tests (CATT and LATEX) showed poor specificity and were deemed inappropriate for saliva-based diagnosis.

Conclusions:

• Detection of trypanosome-specific antibodies in saliva is feasible using indirect ELISA.
• Saliva-based antibody detection offers a potential non-invasive method for sleeping sickness diagnosis.
• Further development could lead to a simple, reliable saliva field test for sleeping sickness.