The World Health Organization (WHO) aims to eliminate sexually transmitted infection (STI) epidemics as significant public health threats by 2030. One of the four main non-viral and curable STIs, trichomoniasis, stays persistent, affecting 156 million out of 376 million individuals aged 15–49 in 2016. About 70–85% of persons with trichomoniasis show no signs of infection, highlighting the urgent need for accurate, fast, and accessible detection of Trichomonas vaginalis, the parasite that causes the infection.

Dr. Christine Aubrey Justo and Dr. Windell Rivera of the University of the Philippines – Diliman College of Science’s Institute of Biology (UPD-CS IB), along with colleagues from Spain, Belgium, and the Democratic Republic of the Congo, developed an alternative detection method for T. vaginalis. Instead of using antibodies, they used aptamers—short DNA strands that form 3D shapes and bind to specific targets, in this case, proteins related to T. vaginalis.

“In this research, we conducted a series of sandwich enzyme-linked aptamer-based assays (ELAAs) to determine which of the ten aptamers that were previously selected in another study, can be paired to detect low concentrations of the parasite,” Dr. Justo explained. Sandwich ELAA is a multistep process that can be used to analyze multiple samples at one time. With their study results showing that the combination of a short aptamer (A1_14mer) and a long aptamer (A6) can be used in this process to detect T. vaginalis in clinical samples, the researchers can now adapt the sandwich ELAA to develop more affordable, easy-to-use, and rapid tests for its detection. One such adaptation is the recently reported aptamer-based lateral flow assay. “With the flexible and amplifiable nature of aptamers (unlike antibodies), many more aptamer-based POCTs for trichomoniasis can be created. However, funding and attention to trichomoniasis is very limited. Additional financial and clinical partners are needed before we can start implementing them in healthcare units” Dr. Justo concluded.

Using the knowledge gained in the sandwich ELAA study, various aptamer-based tests can be developed to fill the gap on the  low-cost, rapid tests for trichomoniasis, which has been included in the WHO global research priorities for STIs. Having access to rapid and affordable tests for T. vaginalis detection can help identify the impact of trichomoniasis and create effective strategies for controlling its spread, managing complications, and treating the infection.

Their research paper, titled “Sandwich Enzyme-Linked Aptamer-Based Assay for the Detection of Trichomonas vaginalis,” was published in the international journal Analytical Biochemistry: Methods in the Biological Sciences. This journal features scientific research on methodologies in different fields of biology, including biochemistry, molecular genetics, cell biology, proteomics, immunology, and bioinformatics.

References:

Justo, C. A., Jauset-Rubio, M., Svobodova, M., Skouridou, V., Cools, P., Mulinganya, G., Ibáñez-Escribano, A., Rivera, W. L., & O’Sullivan, C. K. (2024). Sandwich enzyme-linked aptamer-based assay for the detection of trichomonas vaginalis. Analytical Biochemistry, 695, 115656. https://doi.org/10.1016/j.ab.2024.115656