马达加斯加三个疟疾传播地区恶性疟原虫种群的遗传多样性。
Genetic diversity of Plasmodium falciparum populations in three malaria transmission settings in Madagascar.
机构信息
National Malaria Control Programme of Madagascar, Androhibe, Antananarivo, Madagascar.
Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar.
出版信息
Malar J. 2021 May 27;20(1):239. doi: 10.1186/s12936-021-03776-1.
BACKGROUND
Assessment of the genetic diversity of Plasmodium falciparum parasites from various malaria transmission settings could help to define tailored local strategies for malaria control and elimination. Such assessments are currently scarce in Madagascar. The study presented here aimed to bridge this gap by investigating the genetic diversity of P. falciparum populations in three epidemiological strata (Equatorial, Tropical and Fringes) in Madagascar.
METHODS
Two-hundred and sixty-six P. falciparum isolates were obtained from patients with uncomplicated malaria enrolled in clinical drug efficacy studies conducted at health centres in Tsaratanana (Equatorial stratum), Antanimbary (Tropical stratum) and Anjoma Ramartina (Fringes) in 2013 and 2016. Parasite DNA was extracted from blood samples collected before anti-malarial treatment. Plasmodium species were identified by nested PCR targeting the 18 S rRNA gene. The genetic profiles of P. falciparum parasites were defined by allele-specific nested PCR on the polymorphic regions of the msp-1 and msp-2 genes.
RESULTS
Fifty-eight alleles were detected in the P. falciparum samples tested: 18 alleles for msp-1 and 40 for msp-2. K1 (62.9%, 139/221) and FC27 (69.5%, 114/164) were the principal msp-1 and msp-2 allele families detected, although the proportions of the msp-1 and msp-2 alleles varied significantly between sites. Polyclonal infections were more frequent at sites in the Equatorial stratum (69.8%) than at sites in the Tropical stratum (60.5%) or Fringes (58.1%). Population genetics analyses showed that genetic diversity was similar between sites and that parasite flow within sites was limited.
CONCLUSIONS
This study provides recent information about the genetic diversity of P. falciparum populations in three transmission strata in Madagascar, and valuable baseline data for further evaluation of the impact of the control measures implemented in Madagascar.
背景
评估来自不同疟疾传播地区的恶性疟原虫寄生虫的遗传多样性有助于确定针对疟疾控制和消除的定制化当地策略。在马达加斯加，这种评估目前非常缺乏。本研究旨在通过调查马达加斯加三个流行病学层次（赤道、热带和边缘）的恶性疟原虫种群的遗传多样性来填补这一空白。
方法
2013 年和 2016 年，从在 Tsaratanana（赤道层）、Antanimbary（热带层）和 Anjoma Ramartina（边缘）的卫生中心进行的临床药物疗效研究中招募的患有无并发症疟疾的患者中获得了 266 个恶性疟原虫分离株。从抗疟治疗前采集的血液样本中提取寄生虫 DNA。通过针对 18S rRNA 基因的嵌套 PCR 鉴定疟原虫种。通过在 msp-1 和 msp-2 基因的多态性区域上进行等位基因特异性嵌套 PCR 来定义恶性疟原虫寄生虫的遗传特征。
结果
在所测试的恶性疟原虫样本中检测到 58 个等位基因：msp-1 有 18 个等位基因，msp-2 有 40 个等位基因。K1（62.9%，139/221）和 FC27（69.5%，114/164）是主要的 msp-1 和 msp-2 等位基因家族，但 msp-1 和 msp-2 等位基因的比例在不同地点之间有显著差异。赤道层地点的多克隆感染（69.8%）比热带层地点（60.5%）或边缘地点（58.1%）更频繁。群体遗传学分析表明，不同地点之间的遗传多样性相似，地点内的寄生虫流动有限。
结论
本研究提供了马达加斯加三个传播层次恶性疟原虫种群遗传多样性的最新信息，为进一步评估马达加斯加实施的控制措施的影响提供了有价值的基线数据。
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