Rapid, sensitive, and convenient detection of Plasmodium falciparum infection based on CRISPR and its application in detection of asymptomatic infection.

ABSTRACT

Rapid and convenient detection of the Plasmodium in clinically diagnosed individuals and asymptomatically infected populations is essential for global malaria eradication, especially in malaria-endemic African countries where medical equipment and professionals are relatively deficient. Here, we described a CRISPR-based diagnostic for the detection of Plasmodium falciparum, the deadliest and most prevalent species of malaria parasite in Africa, via lateral flow strip readout without the need of nucleic acid extraction. The assay exhibited 100% sensitivity on clinical samples (5 P falciparum) and significant consistency with qPCR test on asymptomatic infection samples (49 P falciparum and 51 non-P. falciparum, Kappa=0.839). An artemisinin-resistant P. falciparum strain and 4 other laboratory-cultured strains can also be detected through this assay, whereas no cross-reactivity with Plasmodium vivax was observed. A 0.001% parasitaemia (corresponding to ∼60 parasites/µL) below the "low parasite density" test threshold (200 parasites/µL) is detectable. Our study demonstrated that direct malaria detection using whole blood on the spot and the detection of both clinical and asymptomatic infections of P. falciparum are feasible. This method is expected to be employed for clinical testing and large-scale community screening in Africa and possibly other places, contributing to the accurate diagnosis and control of malaria.