Epidemiological insights and genetic diversity of the Duffy binding protein of Plasmodium vivax in Duffy-negative Cameroonians.

BACKGROUND

Malaria remains a major public health concern in sub-Saharan Africa. Plasmodium vivax (P. vivax), historically considered rare due to the predominance of Duffy-negative individuals, is increasingly reported in Central and West Africa. The ability of P. vivax to infect Duffy-negative populations challenges long-standing assumptions regarding parasite invasion biology and highlight surveillance gaps across Africa.

METHODOLOGY/PRINCIPAL FINDINGS: This study investigated P. vivax prevalence and genetic diversity across three ecological zones in Cameroon. A total of 1,373 samples were screened by microscopy, rapid diagnostic tests (RDTs), and qPCR; and all participants were genotyped for Duffy antigen status. PvDBP1 region II was successfully sequenced from 75 P. vivax isolates. P. vivax prevalence was 10.8% among hospital patients (86/793) and 5.5% in community participants (32/580), and all confirmed infections occurred in Duffy-negative individuals. Hospital infections exhibited significantly higher parasitemia than asymptomatic cases. PvLDH-based RDTs failed to detect over 85% of qPCR-confirmed infections. Genetic analysis of PvDBP1 identified eight nonsynonymous mutations, with I379L (74.1%) and E225K (61.3%) as the most common variants, suggesting possible adaptive evolution. Phylogenetic analysis clustered Cameroonian P. vivaxisolates with those from Botswana, distinct from East African and Asian lineages, indicating regional adaptation and potential gene flow within Central-Southern Africa.

CONCLUSION/SIGNIFICANCE: This study provides the first integrated epidemiological and PvDBP1 genetic characterization of P. vivax infections in Duffy-negative Central Africans, revealing widespread subclinical infections and poor diagnostic performance of current PvLDH-based RDTs. The observed genetic signatures of adaptation highlight the urgent need to prioritize P. vivax within national malaria programs and investigate alternative invasion pathways beyond PvDBP1 to guide improved diagnostic and vaccine strategies.