A Mouthwatering Malaria Test

Malaria claims over 435,000 lives around the globe each year. In our fight to eradicate the disease, early detection of subclinical and asymptomatic infection (and of those who carry the parasite without falling ill) is vital. However, current blood-based tests are invasive, require administration by clinicians, and often cause patients stress. Now, the world’s first saliva-based rapid diagnostic test (RDT) for malaria – backed by a US$1,199,161 (¥138,269,665) grant from Japan’s Global Health Innovative Technology (GHIT) – seeks to offer a simpler, less invasive alternative (1).

A recent report from the World Health Organization’s Strategic Advisory Group on malaria eradication called for more research and the development of innovative diagnostic tools to replace existing blood tests (2). Rhoel Dinglasan and his team at the University of Florida have answered the call by laying the groundwork for a new saliva test called SALVA!. “We set out to discover and identify protein biomarkers specific to Plasmodium falciparum – or the different phases of the parasite in the human body – in fluids other than blood,” says Dinglasan. Their discovery? A new protein biomarker, PSSP17, that is present in saliva and identifies asymptomatic infected individuals who are likely to progress to malaria within a week.

The testing device is designed to allow healthcare professionals, teachers, and parents to carry out the procedure by taking a small saliva sample – no specialist training is required. Thanks to GHIT’s funding, the next step will be to produce 2,000 SALVA! kits, each containing high-affinity recombinant humanized monoclonal antibodies to detect PSSP17 on a lateral flow test. The devices are then set to be tested in either the Democratic Republic of Congo or Uganda in 2020.

“Once launched, we anticipate the tests will be used globally, but specifically in all endemic areas,” explains Dinglasan. “Mass screening for carrier detection will be the first step in the regional elimination process, but detecting early-stage asymptomatic acute disease – in addition to symptomatic acute disease – will require global roll-out.” The test’s accessibility is a particularly enticing goal. “RDTs are crucial in curtailing malaria and, in this case, we have a minimally invasive saliva-based test that is easy to use and doesn’t have to be administered by a healthcare professional. We hope this early detection can finally make the eradication of malaria a reality.”