Presence of additional Plasmodium vivax malaria in Duffy negative individuals from Southwestern Nigeria

Mary Aigbiremo Oboh,Aparup Das,Nazia Anwar Ali,Aida Sadikh Badiane,Upasana Shyamsunder Singh,Daouda Ndiaye,Praveen Kumar Bharti

doi:10.1186/s12936-020-03301-w

Abstract

BackgroundMalaria in sub-Saharan Africa (sSA) is thought to be mostly caused by Plasmodium falciparum. Recently, growing reports of cases due to Plasmodium ovale, Plasmodium malariae, and Plasmodium vivax have been increasingly observed to play a role in malaria epidemiology in sSA. This in fact is due to the usage of very sensitive diagnostic tools (e.g. PCR), which have highlighted the underestimation of non-falciparum malaria in this sub-region. Plasmodium vivax was historically thought to be absent in sSA due to the high prevalence of the Duffy negativity in individuals residing in this sub-continent. Recent studies reporting detection of vivax malaria in Duffy-negative individuals from Mali, Mauritania, Cameroon challenge this notion.MethodsFollowing previous report of P. vivax in Duffy-negative individuals in Nigeria, samples were further collected and assessed RDT and/or microscopy. Thereafter, malaria positive samples were subjected to conventional PCR method and DNA sequencing to confirm both single/mixed infections as well as the Duffy status of the individuals.ResultsAmplification of Plasmodium gDNA was successful in 59.9% (145/242) of the evaluated isolates and as expected P. falciparum was the most predominant (91.7%) species identified. Interestingly, four P. vivax isolates were identified either as single (3) or mixed (one P. falciparum/P. vivax) infection. Sequencing results confirmed all vivax isolates as truly vivax malaria and the patient were of Duffy-negative genotype.ConclusionIdentification of additional vivax isolates among Duffy-negative individuals from Nigeria, substantiate the expanding body of evidence on the ability of P. vivax to infect RBCs that do not express the DARC gene. Hence, such genetic-epidemiological study should be conducted at the country level in order to evaluate the true burden of P. vivax in Nigeria.

Highlights

Malaria in sub-Saharan Africa is thought to be mostly caused by Plasmodium falciparum
In sub-Saharan Africa, the majority (99%) of the malaria infections is thought to be due to Plasmodium falciparum and, rarely by Plasmodium ovale, Plasmodium malariae, while Plasmodium vivax is not even considered as one of the players [1] in shaping malaria epidemiology in sSA
Notwithstanding that, it seems likely that there might be an interplay of both hypotheses, in which case, simultaneous occurrence and selective adaptation of the Duffy negative allele in sSA might have resulted in the absence of vivax malaria in the region

Summary

Introduction

Malaria in sub-Saharan Africa (sSA) is thought to be mostly caused by Plasmodium falciparum. P. vivax has a much wider geographical distribution outside of Africa unlike falciparum malaria The former notion that P. vivax originates from Asia and South America, gradually finds its way into Africa through the trade-route corridor is being opposed by current evidences. These recent proofs support the hypothesis that, P. vivax could have originally evolved from a vivax-like strain detected in non-human primates in Africa [21, 22] and, from there dispersed to other continents during the period of human migration. Later re-introduction of P. vivax into sSA might have happened when individuals expressing the Duffy null allele travels between continents and countries where P. vivax is endemic

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