The epidemiology of Plasmodium vivax among adults in the Democratic Republic of the Congo

Nicholas F Brazeau ,Kyaw L Thwai ,Gregory A Wray ,Corinna Keeler ,Lucy Van Dorp ,Pere Gelabert ,Andreea Waltmann ,Robert Verity ,Antoinette Tshefu ,Michael Emch ,Jonathan B Parr ,Valerie Gartner ,Steven R Meshnick ,Ben Redelings ,Andrew P Morgan ,Molly Deutsch-Feldman ,Joris Losimba Likwela ,Oliver J Watson ,Jessie K Edwards ,C Madeline Mitchell ,Melchior Kashamuka Mwandagalirwa ,Jonathan J Juliano

doi:10.1038/s41467-021-24216-3

Abstract

Reports of P. vivax infections among Duffy-negative hosts have accumulated throughout sub-Saharan Africa. Despite this growing body of evidence, no nationally representative epidemiological surveys of P. vivax in sub-Saharan Africa have been performed. To overcome this gap in knowledge, we screened over 17,000 adults in the Democratic Republic of the Congo (DRC) for P. vivax using samples from the 2013-2014 Demographic Health Survey. Overall, we found a 2.97% (95% CI: 2.28%, 3.65%) prevalence of P. vivax infections across the DRC. Infections were associated with few risk-factors and demonstrated a relatively flat distribution of prevalence across space with focal regions of relatively higher prevalence in the north and northeast. Mitochondrial genomes suggested that DRC P. vivax were distinct from circulating non-human ape strains and an ancestral European P. vivax strain, and instead may be part of a separate contemporary clade. Our findings suggest P. vivax is diffusely spread across the DRC at a low prevalence, which may be associated with long-term carriage of low parasitemia, frequent relapses, or a general pool of infections with limited forward propagation.

Highlights

Reports of P. vivax infections among Duffy-negative hosts have accumulated throughout subSaharan Africa
In conducting a sensitivity analysis on the coding of net-use, we found that our primary exposure, insecticide-treated net (ITN) use, contained the null for both the unweighted (Supplementary Table 7) and inverse probability weights (IPWs)-approach (Fig. 2) but that the Demographic Health Survey (DHS) longlasting insecticide net use variable only contained the null for the unweighted approach (OR: 0.75, 95% CI: 0.55, 1.01)
From our spatially robust dataset, we detected 467 P. vivax infections corresponding to a Democratic Republic of the Congo (DRC) national prevalence of 2.96%

Summary

Introduction

Reports of P. vivax infections among Duffy-negative hosts have accumulated throughout subSaharan Africa Despite this growing body of evidence, no nationally representative epidemiological surveys of P. vivax in sub-Saharan Africa have been performed. If P. vivax were returning or reemerging in SSA as a new epidemic, it would have the potential to undermine years of malaria control and elimination efforts To address this critical gap in knowledge, we used samples from the Democratic Republic of the Congo (DRC) 2013–2014 Demographic Health Survey (DHS) to screen a nationally representative population of over 17,000 adults for P. vivax. Findings from the DRC are highly relevant for contextualizing vivax malaria in SSA Using this nationally representative survey, we provide a national level estimate of P. vivax prevalence, associated risk factors, and the geographical distribution of cases across the DRC. By coupling a nationally representative, spatially rich dataset with robust risk factor and spatial analysis, we advance efforts to uncover the hidden distribution of P. vivax in SSA

Methods

Results

Conclusion