High frequency of the Duffy-negative genotype and absence of Plasmodium vivax infections in Ghana

Abstract

Background Recent studies from different malaria-endemic regions including western Africa have now shown that Plasmodium vivax can infect red blood cells (RBCs) and cause clinical disease in Duffy-negative people, though the Duffy-negative phenotype was thought to confer complete refractoriness against blood invasion with P. vivax. The actual prevalence of P. vivax in local populations in Ghana is unknown and little information is available about the distribution of Duffy genotypes. The aim of this study was to assess the prevalence of P. vivax in both asymptomatic and symptomatic outpatients and the distribution of Duffy genotypes in Ghana. Methods DNA was extracted from dried blood spots (DBS) collected from 952 subjects (845 malaria patients and 107 asymptomatic persons) from nine locations in Ghana. Plasmodium species identification was carried out by nested polymerase chain reaction (PCR) amplification of the small-subunit (SSU) rRNA genes. For P. vivax detection, a second PCR of the central region of the Pvcsp gene was carried out. Duffy blood group genotyping was performed by allele-specific PCR to detect the presence of the FYES allele. Results No cases of P. vivax were detected in any of the samples by both PCR methods used. Majority of infections (542, 94.8%) in the malaria patient samples were due to P. falciparum with only 1 infection (0.0017%) due to Plasmodium malariae, and 2 infections (0.0034%) due to Plasmodium ovale. No case of mixed infection was identified. Of the samples tested for the FYES allele from all the sites, 90.5% (862/952) had the FYES allele. All positive samples were genotyped as FY*B-33/FY*B-33 (Duffy-negative homozygous) and therefore classified as Fy(a−b−). Conclusions No cases of P. vivax were detected by both PCRs and majority of the subjects tested carried the FYES allele. The lack of P. vivax infections observed can be attributed to the high frequency of the FYES allele that silences erythroid expression of the Duffy. These results provide insights on the host susceptibility for P. vivax infections that had not been investigated in Ghana before.

African Plasmodium vivax malaria improbably rare or benign

“…Dongho et al [48] reported 177 of 500 febrile outpatients positive for P. vivax at Dschang, Cameroon, but the infection was infrequent (3 of 501) at two other locations. A PCR survey of 952 residents of Ghana proved that they were wholly negative for P. vivax [49]. In 2022, Wilairatana et al [50] reported a systematic review and meta-analysis of the prevalence and risk of P. vivax in Duffy-negative individuals.…”

Limited Reliability of the Molecular Detection of Plasmodium spp. from Incubated Blood Culture Samples for Forensic Purposes

“…Of note, a minority of samples did not contain sufficient target DNA to allow a conclusive discrimination. Further, the occurrence of P. vivax in Ghana is considered as not confirmed so far [40]. In this study, two real-time PCR signals that were suggestive of the abundance of low amounts of P. vivax DNA, but no microscopical proof, were recorded.…”

Plasmodium vivax Duffy Binding Protein-Based Vaccine: a Distant Dream

“…However, Duffy-negative individuals infected with P. vivax have been reported in sub-Saharan Africa ( Ryan et al., 2006 ; Gosi et al., 2008 ; Ménard et al., 2010 ; Woldearegai et al., 2013 ; Djeunang Dongho et al., 2021 ), which points to the fact that there might be an alternative route of invading human reticulocytes lacking DARC. A recent study conducted in 952 individuals observed the absence of P. vivax infections in Ghana where a high frequency of the Duffy-negative genotype was reported ( Brown et al., 2021 ). Human P. vivax strains have been reported in Madagascar and parts of Africa, which might be due to the re-establishment of this parasite ( Culleton and Carter, 2012 ).…”