Modeling the relative contribution of relapses to Plasmodium vivax infection in Brazil

Abstract

Nearly 130,000 laboratory-confirmed cases of malaria were recorded in Brazil in 2016, 99.5% of them acquired in the Amazon Basin. Plasmodium vivax accounts for 88% of the malaria burden in this country, with P. falciparum being the second most prevalent malaria parasite. New episodes of P. vivax blood-stage infection may be caused by new inoculations with sporozoites (primary infections) or by reactivation of dormant liver stages, known as hypnozoites, that were generated in previous infections (relapses). The relative contribution of primary infections and relapses to the overall P. vivax burden, previously investigated in meso-to hyperendemic areas of Thailand and Papua New Guinea, remains unknown in areas of relatively low malaria transmission in Brazil. We aim, through this international research collaboration, to refine and apply a mathematical model to describe the dynamics of P. vivax infection and estimate the relative contribution of hypnozoite reactivation in a major malaria-endemic site in Brazil. Moreover, we aim to organize a three-day research workshop in São Paulo to set the stage for further research collaboration between the University of São Paulo (USP) and the University of New South Wales (UNSW) in the area of mathematical epidemiology of malaria. (AU)