Biological Sciences, University of North Carolina at Charlotte, USA.
Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy.
Int J Infect Dis. 2021 Jul;108:63-71. doi: 10.1016/j.ijid.2021.05.009. Epub 2021 May 12.
Plasmodium vivax malaria was thought to be rare in Africans who lack the Duffy blood group antigen expression. However, recent studies indicate that P. vivax can infect Duffy-negative individuals and has spread into areas of high Duffy negativity across Africa. Our study compared epidemiological and genetic features of P. vivax between African regions.
A standardized approach was used to identify and quantify P. vivax from Botswana, Ethiopia, and Sudan, where Duffy-positive and Duffy-negative individuals coexist. The study involved sequencing the Duffy binding protein (DBP) gene and inferring genetic relationships among P. vivax populations across Africa.
Among 1215 febrile patients, the proportions of Duffy negativity ranged from 20-36% in East Africa to 84% in southern Africa. Average P. vivax prevalence among Duffy-negative populations ranged from 9.2% in Sudan to 86% in Botswana. Parasite density in Duffy-negative infections was significantly lower than in Duffy-positive infections. P. vivax in Duffy-negative populations were not monophyletic, with P. vivax in Duffy-negative and Duffy-positive populations sharing similar DBP haplotypes and occurring in multiple, well-supported clades.
Duffy-negative Africans are not resistant to P. vivax, and the public health significance of this should not be neglected. Our study highlights the need for a standardized approach and more resources/training directed towards the diagnosis of vivax malaria in Africa.
曾认为缺乏达菲血型抗原表达的非洲人很少患有间日疟原虫疟疾。然而，最近的研究表明，间日疟原虫可以感染达菲阴性个体，并已传播到非洲达菲阴性率较高的地区。本研究比较了非洲不同地区间日疟原虫的流行病学和遗传特征。
采用标准化方法从博茨瓦纳、埃塞俄比亚和苏丹鉴定和定量间日疟原虫，这些地区既有达菲阳性个体也有达菲阴性个体。本研究涉及对达菲结合蛋白（DBP）基因进行测序，并推断非洲各地间日疟原虫种群的遗传关系。
在 1215 例发热患者中，东非的达菲阴性率范围为 20-36%，而南部非洲的达菲阴性率为 84%。达菲阴性人群中的平均间日疟原虫流行率从苏丹的 9.2%到博茨瓦纳的 86%不等。达菲阴性感染中的寄生虫密度明显低于达菲阳性感染。达菲阴性人群中的间日疟原虫不是单系的，达菲阴性和达菲阳性人群中的间日疟原虫共享相似的 DBP 单倍型，并存在于多个支持良好的分支中。
达菲阴性的非洲人并非对间日疟原虫有抵抗力，不应忽视这一公共卫生意义。我们的研究强调需要采取标准化方法，并为非洲间日疟的诊断提供更多资源/培训。
