Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California Irvine, Irvine, CA, 92697, USA.
Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, 5195, Jimma, Ethiopia.
Malar J. 2024 Mar 14;23(1):76. doi: 10.1186/s12936-024-04895-1.
Malaria remains a significant cause of morbidity and mortality in Ethiopia with an estimated 3.8 million cases in 2021 and 61% of the population living in areas at risk of malaria transmission. Throughout the country Plasmodium vivax and Plasmodium falciparum are co-endemic, and Duffy expression is highly heterogeneous. The public health significance of Duffy negativity in relation to P. vivax malaria in Ethiopia, however, remains unclear. This study seeks to explore the prevalence and rates of P. vivax malaria infection across Duffy phenotypes in clinical and community settings.
A total of 9580 and 4667 subjects from community and health facilities from a malaria endemic site and an epidemic-prone site in western Ethiopia were enrolled and examined for P. vivax infection and Duffy expression from February 2018 to April 2021. Association between Duffy expression, P. vivax and P. falciparum infections were examined for samples collected from asymptomatic community volunteers and symptomatic subjects from health centres.
Infection rate of P. vivax among Duffy positives was 2-22 fold higher than Duffy negatives in asymptomatic volunteers from the community. Parasite positivity rate was 10-50 fold higher in Duffy positives than Duffy negatives among samples collected from febrile patients attending health centres and mixed P. vivax and P. falciparum infections were significantly more common than P. vivax mono infections among Duffy negative individuals. Plasmodium vivax parasitaemia measured by 18sRNA parasite gene copy number was similar between Duffy positives and Duffy negatives.
Duffy negativity does not offer complete protection against infection by P. vivax, and cases of P. vivax in Duffy negatives are widespread in Ethiopia, being found in asymptomatic volunteers from communities and in febrile patients from health centres. These findings offer evidence for consideration when developing control and intervention strategies in areas of endemic P. vivax and Duffy heterogeneity.
疟疾仍然是埃塞俄比亚发病率和死亡率的一个重要原因，据估计，2021 年有 380 万例疟疾病例，61%的人口生活在疟疾传播风险地区。在全国范围内，间日疟原虫和恶性疟原虫共同流行，Duffy 表达高度异质。然而，Duffy 阴性与埃塞俄比亚间日疟之间的公共卫生意义仍不清楚。本研究旨在探讨临床和社区环境中不同 Duffy 表型的间日疟原虫感染的流行率和感染率。
2018 年 2 月至 2021 年 4 月，从埃塞俄比亚一个疟疾流行地区和一个流行地区的卫生机构共招募了 9580 名和 4667 名社区和卫生机构的居民，检查间日疟原虫感染和 Duffy 表达情况。对来自无症状社区志愿者和卫生中心就诊的有症状患者的样本，检查 Duffy 表达与间日疟原虫和恶性疟原虫感染之间的关系。
在来自社区的无症状志愿者中，Duffy 阳性者的间日疟原虫感染率比 Duffy 阴性者高 2-22 倍。在来自卫生中心就诊的发热患者的样本中，Duffy 阳性者的寄生虫阳性率比 Duffy 阴性者高 10-50 倍，而且 Duffy 阴性者中混合感染间日疟原虫和恶性疟原虫比单纯感染间日疟原虫更为常见。通过 18sRNA 寄生虫基因拷贝数测量的间日疟原虫寄生虫血症在 Duffy 阳性者和 Duffy 阴性者之间相似。
Duffy 阴性并不能完全防止间日疟原虫感染，间日疟原虫在 Duffy 阴性者中在埃塞俄比亚广泛存在，在来自社区的无症状志愿者和来自卫生中心的发热患者中都有发现。这些发现为在间日疟原虫和 Duffy 异质性流行地区制定控制和干预策略提供了证据。
