[Use of genetic material extracted from rapid malaria diagnostic tests using PCR during the Grand Magal of Touba in Senegal].

INTRODUCTION

The Grand Magal of Touba (GMT), a religious event, attracts between four and five million pilgrims and poses a significant risk of infectious disease transmission, including malaria. Rapid diagnostic tests (RDTs) are commonly used during the event. This study aimed to validate the use of genetic material extracted from RDTs for retrospective diagnostic testing by PCR.

METHODS

Two types of RDTs were collected from eight health facilities in the Mbacke department in 2022 and 2023 during the GMT: Bioline™ Malaria Ag P.f/Pan (Abbott, USA) and ParaHIT® (Arkray, India) which detects Plasmodium falciparum. Real-time PCR (qPCR) was performed after opening the RDTs and extracting DNA/RNA to confirm the visual reading of the antigen tests. The performance of the collected RDTs was calculated relative to the PCR results, which were considered the reference standard.

RESULTS

A total of 2,381 RDTs were collected, 213 of which (8.9%) were positive according to the test readings (135 according to Bioline™ tests, and 78 according to ParaHIT). According to qPCR, 194 samples (8.1%) were positive for P. falciparum. There were false positives in 39 (2.5%) Bioline™ Jests and 57 (7.2%) ParaHIT tests, as well as false negatives in 68 (4.3%) Bioline™ tests and 9 (1.1%) ParaHIT® tests. The Bioline™ and ParaHIT® tests were 97.3% and 92.5% specific, respectively. Their positive predictive values were 71.1% and 26.9%, respectively, and their negative predictive values were 95.3% and 98.7%, respectively.

CONCLUSION

Genetic material extracted from RDT cassettes can be used for subsequent PCR diagnosis with increased specificity and sensitivity.