title: Prolonged parasite clearance in a Chinese splenectomized patient with falciparum malaria imported from Nigeria.
abstract: BACKGROUND
  The spleen plays a pivotal role in the rapid clearance of parasitized red blood cells in patients with falciparum malaria after artemisinin treatment. Prolonged parasite clearance can be found in patients who have had a splenectomy, or those with hemoglobin abnormalities and/or reduced immunity, which are all distinguishable from artemisinin resistance. This paper reports on a case of prolonged parasite clearance in a Chinese splenectomized patient with falciparum malaria imported from Nigeria.
  
  
  METHODS
  A 35-year-old Chinese male suffered 2 days of febrile illness after returning to Zhumadian city of Henan province from Nigeria on October 1, 2014. The main symptoms were febrile, including the highest axillary temperature of 40 °C, headache, and chills. A peripheral blood smear showed parasitemia (53 913 asexual parasites/μl) of Plasmodium falciparum. The patient had not used any chemoprophylaxis against malaria in Nigeria when he worked there as a construction worker between 2009 and 2014. The patient had three episodes of malaria in Nigeria and had a splenectomy due to a traffic accident 8 years ago from the time he was admitted to hospital. The patient was orally administrated a total of 320 mg/2.56 g dihydroartemisinin-piperaquine for 2 days and intravenously administrated a total of 3 000 mg artesunate for 18 days. The axillary temperature of the patient ranged between 37.0 and 37.7 °C from Day 0 to Day 3, and blood microscopy revealed falciparum malaria parasitemia (26 674 asexual parasites/μl) on Day 3. The patient was afebrile on Day 4, falciparum malaria parasitemia was continuously present and then gradually decreased on the next days, and was negative on Day 21. The patient was cured and left hospital on Day 24 after no plasmodium falciparum was found in the blood on Day 21 to Day 23. No mutation was found in the K13 propeller gene when compared with the PF3D7_1343700 K13 propeller gene reference sequence.
  
  
  CONCLUSIONS
  This is the first reported case in China of prolonged parasite clearance in a splenectomized patient with imported falciparum malaria. Artemisinin resistance should be distinguished when prolonged parasite clearance is found in a malaria patient who has had splenectomy.
authors.affiliation: Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, People's Republic of China. Zhwei69@163.com.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Zhang
authors.affiliation: Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China.
authors.forename: San-Jin
authors.initials: SJ
authors.lastname: Li
authors.affiliation: School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Hu
authors.affiliation: Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China.
authors.forename: Yong-Min
authors.initials: YM
authors.lastname: Yu
authors.affiliation: Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, People's Republic of China.
authors.forename: Cheng-Yun
authors.initials: CY
authors.lastname: Yang
authors.affiliation: Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, People's Republic of China.
authors.forename: Rui-Min
authors.initials: RM
authors.lastname: Zhou
authors.affiliation: Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Tang
authors.affiliation: Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China.
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Wang
authors.affiliation: Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China.
authors.forename: Xiu-Yun
authors.initials: XY
authors.lastname: Wang
authors.affiliation: Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China.
authors.forename: Yong-Xiang
authors.initials: YX
authors.lastname: Sun
authors.affiliation: School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.
authors.forename: Zhan-Chun
authors.initials: ZC
authors.lastname: Feng
authors.affiliation: Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, People's Republic of China. Bianlixu@163.com.
authors.forename: Bian-Li
authors.initials: BL
authors.lastname: Xu
mesh_terms: D000328:Adult; D000818:Animals; D000962:Antimalarials / Q000627:therapeutic use; D037621:Artemisinins / Q000627:therapeutic use; D002681:China; D006801:Humans; D016778:Malaria, Falciparum / Q000097:blood / Q000188:drug therapy* / Q000469:parasitology*; D008297:Male; D009549:Nigeria; D010963:Plasmodium falciparum / Q000302:isolation & purification; D013156:Splenectomy / Q000009:adverse effects*; D014195:Travel
chemical_list: D000962:Antimalarials; D037621:Artemisinins; C031327:artemisinin
keywords: Artemisinin treatment; China; Falciparum malaria; Nigeria; Prolonged parasite clearance; Splenectomy