Duarte Denise, Manuel Francisco, Dias Ana, Sacato Esmeralda, Taleingue Elsa, Daniel Elsa, Simão Francisco, Varandas Luis, Antunes Maria Lina, Nogueira Fatima
Global Health and Tropical Medicine, GHTM, Associate Laboratory in Translation and Innovation Towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Rua da Junqueira 100, 1349-008, Lisbon, Portugal.
Faculdade de Medicina, Universidade Agostinho Neto, Rua Principal da Camama, Distrito da Cidade Universitária CP 815, Luanda, Angola.
Malar J. 2025 Jan 10;24(1):5. doi: 10.1186/s12936-024-05240-2.
Malaria is the parasitic disease with the highest global morbidity and mortality. According to estimates from the World Health Organization (WHO), there were around 249 million cases in 2022, with 3.4% occurring in Angola. The emergence and spread of drug-resistant Plasmodium falciparum have compromised anti-malarial efficacy and threatens malaria elimination campaigns using artemisinin-based combination therapy (ACT). Increased copy number (CNV) of the P. falciparum gene plasmepsin 2 (pfpm2) have been reported to confer parasite tolerance to piperaquine (PPQ) and the multidrug resistance-1 (pfmdr1), resistance to mefloquine (MEF) and decreased susceptibility to lumefantrine (LUM). PPQ, MEF and LUM are ACT partner drugs. Therefore, CNV detection is a useful tool to track ACT resistance risk. The potential for future treatment failure of artemisinin-based combinations (that include PPQ, LUM and AMQ), due to parasite resistance in the region, emphasizes the need for continued molecular surveillance.
One hundred and nine clinically derived samples were collected at Hospital Central Dr. António Agostinho Neto (HCL) in Lubango, Angola. qPCR targeting the small-subunit 18S rRNA gene was used to confirm P. falciparum infection. Copy number estimates were determined using a SYBR green-based quantitative PCR assay.
Overall, this study revealed a low number of resistance CNVs present in the parasite population at Lubango, for the genes pfmdr1 and pfpm2. Of the 102 samples successfully analysed for pfpm2 10 (9.8%) carried increased CNV and 9/101 (8.9%) carried increased CNV of pfmdr1.
This study provides, for the first time, evidence for the presence of CNVs in the pfpm2 and pfmdr1 genes in P. falciparum isolates from southern Angola.
疟疾是全球发病率和死亡率最高的寄生虫病。根据世界卫生组织（WHO）的估计，2022年约有2.49亿例疟疾病例，其中3.4%发生在安哥拉。耐青蒿素恶性疟原虫的出现和传播损害了抗疟疗效，并威胁到使用以青蒿素为基础的联合疗法（ACT）的疟疾消除运动。据报道，恶性疟原虫基因胃蛋白酶2（pfpm2）的拷贝数增加（CNV）可使寄生虫对哌喹（PPQ）产生耐受性，多药耐药-1（pfmdr1）对甲氟喹（MEF）产生耐药性，并降低对卤泛群（LUM）的敏感性。PPQ、MEF和LUM是ACT的联合用药。因此，CNV检测是追踪ACT耐药风险的有用工具。由于该地区寄生虫耐药性，基于青蒿素的联合用药（包括PPQ、LUM和阿莫地喹）未来治疗失败的可能性，强调了持续进行分子监测的必要性。
在安哥拉卢班戈的安东尼奥·阿戈斯蒂纽·内图中央医院（HCL）收集了109份临床来源的样本。使用靶向小亚基18S rRNA基因的qPCR来确认恶性疟原虫感染。使用基于SYBR Green的定量PCR测定法确定拷贝数估计值。
总体而言，本研究显示，在卢班戈的寄生虫群体中，pfmdr1和pfpm2基因的耐药CNV数量较少。在成功分析的102份pfpm2样本中，10份（9.8%）的CNV增加，9/101份（8.9%）的pfmdr1的CNV增加。
本研究首次提供了安哥拉南部恶性疟原虫分离株中pfpm2和pfmdr1基因存在CNV的证据。
