Multiplex testing platform to simultaneously detect and identify Plasmodium species infections for diagnostics and as epidemiological surveillance tool

Malaria remains a significant health threat to military and civilian populations. According to the World Health Organization (WHO), nearly half of the world’s population was at risk of malaria in 2021 and the incidence rates are trending upwards since 2019. The numbers of diagnosed malaria cases in the continental U.S. have reached a 40-year high. Reasons for the unwavering threat of malaria include climate change promoting the expansion of transmission-competent mosquitoes into new geographic areas, and the emergence of insecticide-resistant mosquitoes. The overuse of anti-malarial drugs in the context of preemptively treating patients presenting with febrile disease in malaria-endemic has promoted the emergence of drug-resistant parasites. Various factors have generated a niche for primate Plasmodia to cross over to humans and cause disease. None of the current diagnostic tests detect primate parasites except for Plasmodium knowlesi that is now the fifth human-infecting Plasmodium species. While the WHO implemented a policy that recommends confirmation of malaria prior to treatment, this policy faces several hurdles: (a) lack of resources for obtaining rapid diagnostic tests (RDTs); (b) tropical temperatures and inadequate storage conditions lower the shelf-life of RDTs; (c) lack of skilled technicians proficient in conducting diagnostic tests; (d) inability of some RDTs to distinguish recently resolved and active infections; (e) failure of HRP2/3-based RDTs to detect Plasmodium infections due to increasing prevalence of parasites with deletions; and (f) low sensitivity of diagnostic tests that often fail to detect low parasitemia, which is common in residents of malaria-endemic areas thus impeding efforts toward malaria elimination/eradication efforts as asymptomatic people serve as parasite reservoir in the population. To achieve the objective, two different approaches will be evaluated, namely, detection of parasitic nucleic acids vs. detection of parasitic proteins in patient blood. Both efforts will initially evaluate the sensitivity and specificity of the respective assay. Results will be compared with the performance of RDTs, microscopy, and qPCR. Next, multiplex panels based on the Meso Scale Diagnostic (MSD) platform will be assembled for species identification and their performance will be evaluated. During the advanced phase, the project will determine assay performance when testing saliva and urine. The deliverables of the completed projects are a nucleic-based (for point-of-care settings) and an antigen-based multiplex detection panel (for basic laboratory settings) for ultra-sensitive diagnostics as well as species identification. The MSD platform is uniquely suited for agnostic detection of Plasmodium infection using ultrasensitive multiplexed nucleic acid-based and protein-based probes. The platform has been extensively used by the pharmaceutical industry as well as for DOD applications such as detection of CBRN threats. The types of MSD assays to be developed in this project, i.e., nucleic acid, protein and serology assays, as well as the entire catalog of existing MSD biomarker assays, do not require unique MSD instruments and can be run on the same instrument. Detection of multiple pathogen-specific molecules in a single assay may hold the advantage of a more sensitive and specific assay compared to detecting a single analyte or a few analytes. Multiplex analysis will also enable species identification of the infecting Plasmodium spp, which is critical for determining the treatment strategy.

The research team brings together experts from MSD with extensive expertise in assay development based on molecular vs. antigen-based detection as well as assay commercialization, and experts in malaria diagnostics from the Walter Reed Army Institute of Research. WRAIR also contributes unique samples from clinical and epidemiological studies, a repository of parasite isolates from across the globe, active parasite cultures and a world-renowned insectary. The impact of a diagnostic tool that (a) performs equally well for all Plasmodium species, (b) is equally accurate for patients with high vs. low blood parasite density, (c) can discern resolving vs. active infections, and (d) is not subject to the skills of the performing technician cannot be overstated. The impact ranges from reduction of incorrect treatments (thus improving treatment outcome for individuals), avoiding overuse of anti-malarial drugs (through improved confidence in the accuracy of the diagnosis) thus lowering the risk of promoting the emergence of drug-resistant parasites to supporting identification of individuals with ultra-low parasite burden thus improving the chances of eliminating malaria.

Diagnostics
Product Development
Surveillance

Jun 2024 — May 2028

$1.86M

United States