The clinically silent Plasmodium vivax reservoir in the Amazon: a systematic review and pooled analysis of individual-level data from population-based surveys

• Grant number: 19/23139-0
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2020
• End date: March 31, 2022
• Field of knowledge: Biological Sciences - Parasitology - Protozoology of Parasites
• Agreement: Research Foundation - Flanders (FWO)
• Mobility Program: SPRINT - Projetos de pesquisa - Mobilidade
• Principal Investigator: Marcelo Urbano Ferreira
• Grantee: Marcelo Urbano Ferreira
• Principal researcher abroad: Anna Rosanas-Urgell
• Institution abroad: Institute of Tropical Medicine Antwerp (ITM) , Belgium
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• City of the host institution: São Paulo
• Associated research grant: 16/18740-9 - Scientific bases for residual malaria elimination in the Brazilian Amazon, AP.TEM

Abstract

The current proposal focuses on the vast but clinically silent human reservoir of P. vivax infection that remains undetected and untreated across the Amazon Basin. We will systematically explore the large volume of individual-level data generated by population-based surveys led by the collaborating investigators in endemic settings in Brazil and Peru, combined with aggregated data generated and published by other investigators across the Amazon, to provide an accurate and up-to-date estimate of the relative contribution of asymptomatic and subpatent infections to the overall P. vivax burden and transmission in the region.We hypothesize that chronic, low-density P. vivax infections that are not associated with typical malaria-related signs and symptoms, being often missed by routinely used diagnostic methods, contribute significantly to malaria transmission in the main hotspots of the Amazon and represent a priority target for more intensive and effective interventions. We also hypothesize that the extensive rural-urban mobility of chronically infected, asymptomatic parasite carriers entails urban malaria risk, as parasites from rural villages are continuously introduced into urban centers and may be locally transmitted, leading to explosive epidemics or sustained endemic propagation. (AU)