Assessment of a highly sensitive rapid diagnostic test for reactive case detection of Plasmodium Falciparum infections in Myanmar.

BACKGROUND

Recent epidemiological data indicate that 30-50% of all malaria infections are asymptomatic, with parasite densities below the limit of detection of standard diagnostic tests. A highly sensitive rapid diagnostic test (hsRDT) was developed to detect these low-density Plasmodium falciparum infections. This study evaluated the diagnostic performance of both hsRDTs and conventional RDTs (cRDT) in reactive case detection (RACD) activities among individuals (contacts) living and/or working in proximity to an "index case" in Ann Township in Rakhine State, Myanmar.

METHODS

This prospective community-based RACD study was conducted in 2017-2018 among residents aged at least five years old in 50 villages of Ann Township. We assessed the sensitivity, specificity, and positive and negative predictive values of both a hsRDT (NxTek™ Eliminate Malaria Ag P.f) and a cRDT (SD Malaria Ag P.f/P.v) using an ultra-sensitive polymerase chain reaction (usPCR) diagnostic assay as the gold standard.

RESULTS

A total of 1,990 participants, all contacts of 51 index P. falciparum cases, were recruited. Among them, 28 (1.4%) tested positive by cRDT, 78 (3.9%) by hsRDT, and 171 (8.6%) by usPCR for P. falciparum mono-infection. The sensitivity and specificity of the hsRDT were 27.9% (95% CI 18.2-39.6%) and 98.8% (95% CI 98.2-99.4%), respectively, while the sensitivity and specificity of the cRDT were 13.7% (95% CI 7.6-20.7%) and 100% (95% CI 100-100%), respectively. The differences in sensitivity and specificity between hsRDT and cRDT were statistically significant (p < 0.01 for both).

CONCLUSIONS

Although hsRDTs identified more infected contacts than cRDTs during reactive case detection, they have low overall sensitivity compared to usPCR. In resource-limited settings, such as Myanmar, the use of hsRDTs in RACD should be guided by careful consideration of their field feasibility and cost-effectiveness to support malaria elimination efforts. (285 words).