National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology, Schistosomiasis and Filariasis, MOH, and WHO Collaborating Centre for Malaria, Shanghai, People's Republic of China.
Zhejiang Provincial Center for Disease Control and Prevention, Zhejiang, People's Republic of China.
Malar J. 2020 Feb 4;19(1):59. doi: 10.1186/s12936-020-3140-0.
Resistance to anti-malarial drugs hinders malaria elimination. Monitoring the molecular markers of drug resistance helps improve malaria treatment policies. This study aimed to assess the distribution of molecular markers of imported Plasmodium falciparum infections.
In total, 485 P. falciparum cases imported from Africa, Southeast Asia, and Oceania into Zhejiang province, China, from 2016 to 2018 were investigated. Most were imported from Africa, and only a few cases originated in Asia and Oceania. Blood samples were collected from each patient. Plasmodium falciparum chloroquine resistance transporter (Pfcrt) at residues 72-76 and Kelch13-propeller (k13) were determined by nested PCR and DNA sequence.
Wild-type Pfcrt at residues 72-76 was predominant (72.61%), but mutant and mixed alleles were also detected, of which CVIET (22.72%) was the most common. Mutant Pfcrt haplotypes were more frequent in patients from West Africa (26.92%), North Africa (25%), and Central Africa (21.93%). The number of cases of P. falciparum infections was small in Southeast Asia and Oceania, and these cases involved Pfcrt mutant type. For the k13 propeller gene, 26 samples presented 19 different point mutations, including eight nonsynonymous mutations (P441S, D464E, K503E, R561H, A578S, R622I, V650F, N694K). In addition, R561H, one of the validated SNPs in k13, was detected in one patient from Myanmar and one patient from Rwanda. A578S, although common in Africa, was found in only one patient from Cameroon. R622I was detected in one sample from Mozambique and one sample from Somalia. The genetic diversity of k13 was low in most regions of Africa and purifying selection was suggested by Tajima's D test.
The frequency and spatial distributions of Pfcrt and k13 mutations associated with drug resistance were determined. Wild-type Pfcrt was dominant in Africa. Among k13 mutations correlated with delayed parasite clearance, only the R561H mutation was found in one case from Rwanda in Africa. Both Pfcrt and k13 mutations were detected in patients from Southeast Asia and Oceania. These findings provide insights into the molecular epidemiological profile of drug resistance markers in the study region.
抗疟药物的耐药性阻碍了疟疾的消除。监测耐药性的分子标志物有助于改善疟疾治疗政策。本研究旨在评估输入性恶性疟原虫感染的分子标志物的分布。
共调查了 2016 年至 2018 年期间从非洲、东南亚和大洋洲输入浙江省的 485 例恶性疟原虫感染病例。大多数病例来自非洲，只有少数来自亚洲和大洋洲。从每位患者采集血样。采用巢式 PCR 和 DNA 序列分析检测恶性疟原虫氯喹耐药转运蛋白（Pfcrt）72-76 位的野生型和 Kelch13-螺旋（k13）。
72-76 位的野生型 Pfcrt 占优势（72.61%），但也检测到突变和混合等位基因，其中 CVIET（22.72%）最为常见。西非（26.92%）、北非（25%）和中非（21.93%）患者中突变 Pfcrt 单倍型更为常见。东南亚和大洋洲的恶性疟原虫感染病例较少，且这些病例涉及 Pfcrt 突变型。k13 螺旋基因有 26 个样本呈现 19 种不同的点突变，包括 8 种非同义突变（P441S、D464E、K503E、R561H、A578S、R622I、V650F、N694K）。此外，在来自缅甸和卢旺达的 2 位患者中检测到 k13 中一个已验证的 SNP（R561H）。在非洲常见的 A578S 仅在喀麦隆的一位患者中发现。R622I 在莫桑比克和索马里各有 1 个样本中检出。非洲大多数地区 k13 的遗传多样性较低，Tajima 的 D 检验提示纯化选择。
确定了与耐药性相关的 Pfcrt 和 k13 突变的频率和空间分布。野生型 Pfcrt 在非洲占主导地位。在与寄生虫清除延迟相关的 k13 突变中，仅在非洲的卢旺达发现了 1 例 R561H 突变。东南亚和大洋洲的患者均检测到 Pfcrt 和 k13 突变。这些发现为研究区域的耐药性标志物的分子流行病学特征提供了见解。
