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Parasite clearance rates in Upper Myanmar indicate a distinctive artemisinin resistance phenotype: a therapeutic efficacy study

Abstract:

Background Artemisinin resistance in Plasmodium falciparum extends across Southeast Asia where it is associated with worsening partner drug resistance and a decline in the efficacy of frontline artemisinin-based combination therapy. Dihydroartemisinin-piperaquine (DP) is an essential component of preventive and curative treatment in the region, but its therapeutic efficacy has fallen in Cambodia.

Methods A prospective clinical and parasitological evaluation of DP was conducted at two sites in Upper Myanmar between August 2013 and December 2014, enrolling 116 patients with acute uncomplicated falciparum malaria. Patients received DP orally for 3 days together with primaquine 0.25 mg/kg on admission. Parasite clearance half-lives based on 6 hourly blood smears, and day 42 therapeutic responses were assessed as well as parasite K13 genotypes.

Results Median parasite clearance half-life was prolonged, and clearance half-life was greater than 5 h in 21 % of patients. Delayed parasite clearance was significantly associated with mutations in the propeller region of the parasite k13 gene. The k13 F446I mutation was found in 25.4 % of infections and was associated with a median clearance half-life of 4.7 h compared with 2.7 h for infections without k13 mutations (p < 0.001). There were no failures after 42 days of follow-up, although 18 % of patients had persistent parasitaemia on day 3.

Conclusion The dominant k13 mutation observed in Upper Myanmar, F446I, appears to be associated with an intermediate rate of parasite clearance compared to other common mutations described elsewhere in the Greater Mekong Subregion. Discerning this phenotype requires relatively detailed clearance measurements, highlighting the importance of methodology in assessing artemisinin resistance.

Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1186/s12936-016-1240-7

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Publisher:
BioMed Central
Journal:
Malaria Journal More from this journal
Volume:
15
Issue:
1
Article number:
185
Publication date:
2016-03-31
Acceptance date:
2016-03-16
DOI:
EISSN:
1475-2875


Language:
English
Keywords:
Pubs id:
pubs:627574
UUID:
uuid:06146bda-09cd-4477-9f70-fcf2e3a0fb31
Local pid:
pubs:627574
Source identifiers:
627574
Deposit date:
2016-06-23

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