WHO Attacks Credibility of Suspected Drug-Resistant Malaria Case from Angola

[Note: See the latest developments here.]

The World Health Organization (WHO) rejects the findings of a paper describing suspected drug-resistant malaria in a Vietnamese migrant worker returning from Angola. (See previous post.) According to WHO's Pascal Ringwald, "It took 4 months for WHO to discover the truth and we will make sure that there will be retraction from the authors." But Patrick Kachur, chief of the Malaria Branch at the Centers for Disease Control (CDC), said "I doubt there will be a retraction," and that the CDC is going ahead with plans in Angola to search for similar cases and conduct tests on parasite clearance times.

Nearly all aspects of the case have been questioned. WHO has contended that the first line of treatment, artesunate, came from a batch recalled because of quality issues. The second line drugs, dihydroartemisinin and piperaquine, were delivered by nasogastric tube, a departure from preferred practice.  Also, the dose given, 1 mg/ kg given twice a day, achieves lower blood concentrations, according to mathematical models, than the recommended single dose of 2.4 mg/ kg once a day. The third line of treatment, quinine and doxycycline, were also delivered by nasogastric tube instead of intravenously as recommended. (Intravenous quinine was not available.) Still, nasogastric quinine worked, saving the patient's life. 

The apparent failure of the artemesinin-based drugs to clear the patient's malaria parasites has been attributed to hyperparasitemia which can impair clearance of parasites from the blood after they have been killed by the drug. Finally, genetic sequencing of the malaria parasites found them negative for K13, the biomarker associated with drug resistant malaria in Southeast Asia. 

The paper's authors have stood behind their research, refuting, for example, the claim that the artesunate used was of poor quality. But the battle continues. "Maybe," said WHO's Ringwald concerning the refutation. "But," when it comes to retraction, "CDC will," he continued.

All current containment efforts focus on Southeast Asia. The possible case from Angola threatens to expand an already fast-growing front, perhaps accounting for the heated debate.