A 68-year-old man returning from Republic of Côte d'Ivoire (Ivory Coast) was diagnosed with severe
Plasmodium falciparum malaria and treated with intravenous
artesunate followed by oral
dihydroartemisinin-
piperaquine (DHA-PPQ). A month later the patient experienced a new P. falciparum episode; analysis of pfmsp-1 and pfmsp-2 revealed that the
infection was caused by a genetic strain identical to the strain that caused the initial episode, indicating resurgence of the previous
infection. No mutations in genes associated with resistance to
artemisinin derivatives (pfk13) or
piperaquine (pfexonuclease, pfplasmepsin 2/3) were detected, suggesting that treatment failure could have been caused by
drug malabsorption or poor
drug manufacturing practices. A second treatment with
atovaquone-proguanil was successful in eliminating the
infection, with no further relapses. To our knowledge, this is the first description of a treatment failure with both
artesunate and DHA-PPQ in a traveler returning from a
malaria-endemic region. Analysis of molecular markers of resistance to
antimalarial drugs revealed mutations associated with resistance to
sulfadoxine (pfdhps) and
pyrimethamine (pfdhfr), highlighting the important contribution of surveillance of imported
malaria cases to the monitoring of drug resistance globally.