title: Polymorphisms of the artemisinin resistant marker (K13) in Plasmodium falciparum parasite populations of Grande Comore Island 10 years after artemisinin combination therapy.
abstract: BACKGROUND
  Plasmodium falciparum malaria is a significant public health problem in Comoros, and artemisinin combination therapy (ACT) remains the first choice for treating acute uncomplicated P. falciparum. The emergence and spread of artemisinin-resistant P. falciparum in Southeast Asia, associated with mutations in K13-propeller gene, poses a potential threat to ACT efficacy. Detection of mutations in the P. falciparum K13-propeller gene may provide the first-hand information on changes in parasite susceptibility to artemisinin. The objective of this study is to determinate the prevalence of mutant K13-propeller gene among the P. falciparum isolates collected from Grande Comore Island, Union of Comoros, where ACT has been in use since 2004.
  
  
  METHODS
  A total of 207 P. falciparum clinical isolates were collected from the island during March 2006 and October 2007 (n = 118) and March 2013 and December 2014 (n = 89). All isolates were analysed for single nucleotide polymorphisms (SNPs) and haplotypes in the K13-propeller gene using nested PCR and DNA sequencing.
  
  
  RESULTS
  Only three 2006-2007 samples carried SNPs in the K13-propeller gene, one having a synonymous (G538G) and the other having two non-synonymous (S477Y and D584E) substitutions leading to two mutated haplotypes (2.2%, 2/95). Three synonymous mutations (R471R, Y500Y, and G538G) (5.9%, 5/85) and 7 non-synonymous substitutions (21.2%, 18/85) with nine mutated haplotypes (18.8%, 16/85) were found in isolates from 2013 to 2014. However, none of the polymorphisms associated with artemisinin-resistance in Southeast Asia was detected from any of the parasites examined.
  
  
  CONCLUSIONS
  This study showed increased K13-propeller gene diversity among P. falciparum populations on the Island over the course of 8 years (2006-2014). Nevertheless, none of the polymorphisms known to be associated with artemisinin resistance in Asia was detected in the parasite populations examined. Our data suggest that P. falciparum populations in Grande Comore are still effectively susceptible to artemisinin. Our results provide insights into P. falciparum populations regarding mutations in the gene associated with artemisinin resistance and will be useful for developing and updating anti-malarial guidance in Comoros.
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. huangbo198421@126.com.
authors.forename: Bo
authors.initials: B
authors.lastname: Huang
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. dcs19811202@hotmail.com.
authors.forename: Changsheng
authors.initials: C
authors.lastname: Deng
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. 942966792@qq.com.
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authors.lastname: Yang
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. 1121595778@qq.com.
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authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. wangqi198169@163.com.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, PR China. thshg@126.com.
authors.forename: Shiguang
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authors.lastname: Huang
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA. xsu@niaid.nih.gov.|State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, 361005, Fujian, PR China. xsu@niaid.nih.gov.
authors.forename: Xin-zhuan
authors.initials: XZ
authors.lastname: Su
authors.affiliation: The first affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. liuyajun9808@126.com.
authors.forename: Yajun
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authors.lastname: Liu
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. graceguangzhou@qq.com.
authors.forename: Shaoqin
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authors.lastname: Zheng
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. gyz111@hotmail.com.
authors.forename: Yezhi
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authors.lastname: Guan
authors.affiliation: Research Institute of Tropical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. xuqin@163.com.
authors.forename: Qin
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authors.affiliation: Traditional Chinese Medicine Collage, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. 68722514@qq.com.
authors.forename: Jiuyao
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authors.lastname: Zhou
authors.affiliation: Traditional Chinese Medicine Collage, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. 466754442@qq.com.
authors.forename: Jie
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authors.lastname: Yuan
authors.affiliation: National Malaria Control Programme, Moroni, Union of Comoros. anfanebacar@yahoo.fr.
authors.forename: Afane
authors.initials: A
authors.lastname: Bacar
authors.affiliation: National Malaria Control Programme, Moroni, Union of Comoros. kamalsaid2004@yahoo.fr.
authors.forename: Kamal Said
authors.initials: KS
authors.lastname: Abdallah
authors.affiliation: National Malaria Control Programme, Moroni, Union of Comoros. rachadkeke@yahoo.fr.
authors.forename: Rachad
authors.initials: R
authors.lastname: Attoumane
authors.affiliation: Ministry of Health Comoros, Moroni, Union of Comoros. amsamliva@yahoo.com.
authors.forename: Ahamada M S A
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authors.lastname: Mliva
authors.affiliation: Traditional Chinese Medicine Collage, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. 447373997@qq.com.
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Zhong
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, Guangdong, PR China. 489589715@qq.com.
authors.forename: Fangli
authors.initials: F
authors.lastname: Lu
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China. songjpgz@sina.com.
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mesh_terms: D000962:Antimalarials / Q000494:pharmacology* / Q000627:therapeutic use; D037621:Artemisinins / Q000494:pharmacology* / Q000627:therapeutic use; D017507:Comoros / Q000453:epidemiology; D004351:Drug Resistance; D005787:Gene Frequency; D005819:Genetic Markers; D006239:Haplotypes; D006801:Humans; D016778:Malaria, Falciparum / Q000188:drug therapy / Q000453:epidemiology / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA
chemical_list: D000962:Antimalarials; D037621:Artemisinins; D005819:Genetic Markers; C031327:artemisinin