A Long Neglected World Malaria Map: Plasmodium vivax Endemicity in 2010

Abstract

BackgroundCurrent understanding of the spatial epidemiology and geographical distribution of Plasmodium vivax is far less developed than that for P. falciparum, representing a barrier to rational strategies for control and elimination. Here we present the first systematic effort to map the global endemicity of this hitherto neglected parasite.Methodology and FindingsWe first updated to the year 2010 our earlier estimate of the geographical limits of P. vivax transmission. Within areas of stable transmission, an assembly of 9,970 geopositioned P. vivax parasite rate (PvPR) surveys collected from 1985 to 2010 were used with a spatiotemporal Bayesian model-based geostatistical approach to estimate endemicity age-standardised to the 1–99 year age range (PvPR1–99) within every 5×5 km resolution grid square. The model incorporated data on Duffy negative phenotype frequency to suppress endemicity predictions, particularly in Africa. Endemicity was predicted within a relatively narrow range throughout the endemic world, with the point estimate rarely exceeding 7% PvPR1–99. The Americas contributed 22% of the global area at risk of P. vivax transmission, but high endemic areas were generally sparsely populated and the region contributed only 6% of the 2.5 billion people at risk (PAR) globally. In Africa, Duffy negativity meant stable transmission was constrained to Madagascar and parts of the Horn, contributing 3.5% of global PAR. Central Asia was home to 82% of global PAR with important high endemic areas coinciding with dense populations particularly in India and Myanmar. South East Asia contained areas of the highest endemicity in Indonesia and Papua New Guinea and contributed 9% of global PAR.Conclusions and SignificanceThis detailed depiction of spatially varying endemicity is intended to contribute to a much-needed paradigm shift towards geographically stratified and evidence-based planning for P. vivax control and elimination.

Unstable Malaria Transmission in the Southern Peruvian Amazon and Its Association with Gold Mining, Madre de Dios, 2001–2012

“…7,8 The vast majority of cases in Latin America are concentrated in the Amazon region (90%). 9,10 Peru has the third highest number of malaria cases in South America, 6 with significant health 11 and economic 12 impacts. Despite decades of control efforts, 13 malaria remains endemic in the Peruvian Amazon, and has resurged in recent years, 11 posing a significant threat to public health.…”

The Global Public Health Significance of Plasmodium vivax

“…The Malaria Atlas Project (MAP) was founded to address this evidence gap (Hay and Snow, 2006;Hay et al, 2009;Gething et al, 2011a), with an initial focus on P. falciparum, and the resulting global malaria distributions have been used to assess the adequacy and equity in control funding (Pigott et al, 2012), to inform international policy and resource allocation (Anonymous, 2009;Feachem et al, 2009;McLaughlin et al, 2009;World Bank, 2009;Zanzibar Malaria Control Program, 2009;DFID, 2010;Global Partnership to Roll Back Malaria et al, 2010) and to estimate the global burden of disease Gething et al, 2010a;Hay et al, 2010b). A suite of modelled spatial data on P. vivax transmission and endemicity (Guerra et al 2010;Gething et al 2012) and P. vivax vectors (Sinka et al, 2010a(Sinka et al, , 2010b(Sinka et al, , 2011(Sinka et al, , 2012 add to this evidence base for strategic disease-control planning, implementation and monitoring. Here, for the first time, we bring all these mapped data on P. vivax together in one place.…”

Biology of Malaria Transmission

“…Plasmodium vivax typically causes milder infections than P. falciparum but has a much greater geographical distribution (Gething et al 2012). The clinical symptoms of malaria are largely a result of the replication of asexual stages in human blood, but transmission to mosquitoes is only achieved through the development of sexual stages, termed gametocytes.…”