Diagnostic performance and comparison of ultrasensitive and conventional rapid diagnostic test, thick blood smear and quantitative PCR for detection of low-density Plasmodium falciparum infections during a controlled human malaria infection study in Equatorial Guinea

• DOI: 10.1186/s12936-022-04103-y
• Publication Date: 2022-03-24T22:03:56Z
• Authors: Maxmillian Mpina; Thomas C. Stabler; Tobias Schindler; Jose Raso; Anna Deal; Ludmila Acuche Pupu; Elizabeth Nyakarungu; Maria del Carmen ...; Vicente Urbano; Ali Mtoro; Ali Hamad; Maria Silvia A. L...; Beltran Pasialo; Marta Alene Owono...; Matilde Riloha Rivas; Carlos Cortes Falla; Guillermo A. García; Juan Carlos Momo; Raul Chuquiyauri; Elizabeth Saverino; L. W. Preston Church; B. Kim lee Sim; Bonifacio Manguire; Marcel Tanner; Carl Maas; Salim Abdulla; Peter F. Billingsley; Stephen L. Hoffman; Said Jongo; Thomas L. Richie; Claudia A. Dauben...
• Keywords: Parasitology; Rapid diagnostic test; Tropical Medicine; Medical microbiology

Progress towards malaria elimination has stagnated, partly because infections persisting at low parasite densities comprise a large reservoir contributing to ongoing transmission and are difficult detect. This study compared the performance of an ultrasensitive rapid diagnostic test (uRDT) designed detect density conventional RDT (cRDT), expert microscopy using Giemsa-stained thick blood smears (TBS), quantitative polymerase chain reaction (qPCR) during controlled human infection (CHMI) conducted in exposed adults (NCT03590340).Blood samples were collected from healthy Equatoguineans aged 18-35 years beginning on day 8 after CHMI with 3.2 × 103 cryopreserved, infectious Plasmodium falciparum sporozoites (PfSPZ Challenge, strain NF54) administered by direct venous inoculation. qPCR (18s ribosomal DNA), uRDT (Alere™ Malaria Ag P.f.), cRDT [Carestart Pf/PAN (PfHRP2/pLDH)], TBS performed daily until volunteer became positive treatment was administered. reference for presence parasites.279 24 participants; 123 qPCR. detected 24/123 (19.5% sensitivity [95% CI 13.1-27.8%]), 21/123 (17.1% 11.1-25.1%]), 10/123 (8.1% 4.2-14.8%]); all 100% specific did not any more sensitive than (TBS vs. p = 0.015; 0.053), detecting parasitaemias as 3.7 parasites/µL (p/µL) uRDT) 5.6 p/µL (cRDT) based measurements. TBS, 70/123 below 5.86 p/µL, corresponding TBS. The median prepatent periods days (ranges) 14.5 (10-20), 18.0 (15-28), (15-20) (16-24) qPCR, cRDT, respectively; parasitaemia significantly earlier (3.5 days) other tests.TBS had similar sensitivities, both neither matched parasitaemia. could be considered alternative selected applications, such or field diagnosis, where qualitative, dichotomous results might sufficient.