Despite significant decline in the global malaria burden resulting from concerted international effort over the last decade, malaria infection is a major public health concern that affects more than 200 million people worldwide. Case management is effectively achieved in symptomatic patients with readily available means of diagnosis, but the large number of individuals with subclinical infection cannot be effectively identified, hindering progress in malaria surveillance and control activities.
Current molecular polymerase chain reaction (PCR) techniques play an important role in detecting low-density malaria infection with utmost sensitivity and specificity. Antibody-based enzyme-linked immunosorbent assays (ELISAs) or rapid diagnostic tests (RDTs) that are easy to use and quickly provide results offer an alternative platform for detecting malaria infection by targeting parasite antigens.
We developed an ultra-sensitive multiplex quantitative ELISA that enables simultaneous detection of P. falciparum and P. vivax malaria and screening of host inflammatory response using multiple biomarkers, including histidine-rich protein 2, Plasmodium species-specific epitopes of lactate dehydrogenase, and C-reactive protein. In comparison to PCR, the results of our assay evaluation using clinical specimens demonstrate that this reference test offers good sensitivity and specificity, allowing detection of malaria antigens at sub-ng/mL levels, while differentiating subclinical Plasmodium infections from non-infections.
This tool will support development of new field diagnostic tests by RDT manufacturers and be useful for mass surveillance of malaria.