A case report of late treatment failure in Plasmodium falciparum malaria in a traveler from the Democratic Republic of the Congo to India

A young male returned from the Democratic Republic of the Congo (DRC) to India after four months during his official work. Within a week of his arrival, he developed a high-grade fever with nausea and was hospitalized in a private hospital in New Delhi. He was diagnosed with malaria, treated with an artesunate injection as antimalarial, and discharged on day 5th from the hospital. A week later, he was diagnosed with malaria and dengue positive at ICMR-National Institute of Malaria Research, New Delhi. Artesunate with sulphadoxine and pyrimethamine (AS+SP) was administered following India's malaria treatment policy. However, high-grade fever, along with the asexual stage of the P. falciparum parasite, was observed within 28 days of treatment with AS+SP, signifying late treatment failure (LTF). Further, the molecular analysis from both the days of episodes was analyzed using genomic DNA from dried blood spots, revealing resistance to sulphadoxine-pyrimethamine with mutations at codons pfdhfr 51I, pfdhfr 59 R, pfdhfr 108 N, pfdhps 437 A, pfdhps 581 G. No functional mutation associated was found in pfKelch13, but interestingly the sensitive codons to chloroquine (CQ) (wild type pfcrtK76 and pfmdrN86) revealed the probably reversible CQ sensitivity in the sample from DRC.