A broad range of P. vivax proteins can rapidly and effectively induce a robust and lasting IgG antibody response, even after low-density asymptomatic infections.1 As these responses persist for months or even years after clearance of blood-stage parasites, such antibodies represent ideal biomarkers of both past exposure and concurrent infections. Given that almost all P. vivax hypnozoite carriers did experience a primary blood-stage infection in the preceding 6-9 months, antibody responses are thus also potential biomarkers of hypnozoite carriage. We have used these anti-vivax antibody response patterns to develop a panel of serological exposure markers (SEMs) to P. vivax infections that could promote the identification of people at risk of carrying clinically silent hypnozoites hence that should be targeted with anti-hypnozoite therapy.2 In preliminary studies in Indonesia, serological testing using these markers identified 85% of people experiencing a relapse (Mueller, Noviyanti personal communication).
We assessed the specificity and sensitivity of these candidate antigen proteins in a Cambodian cohort and their application in field trials in Cambodia. The development and adoption of a serological testing and treatment approach (SeroTAT) where upon population screening only individuals testing positive for recent P. vivax exposure with a point-of contact test receive treatment, could provide a valid alternative to current mass-testing and treatment (MTAT) and mass drug administration (MDA) strategies and significantly reduce vivax prevalence and transmission rate globally.