Monitoring of Molecular Markers of Artemisinin Resistance Through Repeated Cross-sectional Assessments in DR Congo, Nigeria and Uganda

Currently, 16 African countries include the use of pre-referral rectal artesunate (RAS) in their treatment policies and a number of countries have begun to implement RAS. However, guidelines for RAS use vary widely across countries and often do not align with WHO recommendations. Of particular concern in this context is the inappropriate use of RAS as a monotherapy (i.e. without subsequent ACT treatment).

In the frame of the Unitaid-funded "Community Access to Rectal Artesunate for Malaria" (CARAMAL) Project, quality-assured (QA) RAS will be rolled out through integrated Community Case Management (iCCM) schemes in selected areas of the Democratic Republic of the Congo (DRC), Nigeria and Uganda. The goal of the CARAMAL Project is to contribute to reducing malaria mortality in children by improving the community management of suspected severe malaria cases. The project will contribute to this goal by advancing the development of operational guidance to catalyse effective and appropriate scale-up of quality-assured rectal artesunate (RAS) as pre-referral treatment of severe malaria.

In the frame of the CARAMAL project, approximately 3,000 treatments of RAS will be dispensed by trained community health workers to children <5 years of age in each project country per year. Children treated with pre-referral RAS will be referred to a higher-level health facility for comprehensive clinical management, including the administration of a full course of an artemisinin-based combination therapy, as per WHO guidelines.

While phenotypic resistance of the Plasmodium parasites against artemisinin has not yet been document in the study settings, this potential threat is a major concern. The administration of artemisinin monotherapies increases drug pressure, which may lead to the selection of drug resistance conferring mutations. Mutations in portions of a P. falciparum gene encoding kelch (K13)-propeller domains are the currently known major determinant of partial resistance against artemisinin. Data on artemisinin resistance of Plasmodium parasites in the CARAMAL Project countries are patchy. K13-propeller polymorphisms previously reported from Cambodia have been found e.g. in parasites from northern Uganda, but the mutations linked to artemisinin resistance were uncommon and did not seem to increase over time. The general notion is that numerous K13 polymorphisms circulate in Africa but their distribution does not currently support the spread of artemisinin resistance.

Linked to the tracking of (severe) malaria patients in the frame of the CARAMAL project, this study will assess the frequency of artemisinin resistance markers in the study settings and tentatively assess whether the introduction of RAS could increase the selection of resistant P. falciparum strains. The study will be conducted in close collaboration with the Global Malaria Programme of the WHO. Finger-prick blood samples will be collected from children < 5 years of age with signs of severe febrile illness and a positive mRDT presenting to community-based providers and referral facilities before and after the pilot roll-out of pre-referral RAS at community level.

Dried blood spots on filter papers will be sent to a WHO-chosen laboratory (Malaria Molecular Epidemiology Unit at the Pasteur Institute in Cambodia) for molecular analyses to assess the presence of markers of artemisinin resistance (K13-propeller sequence polymorphisms).

Inclusion criteria

• age below 5 years
• enrolled in CARAMAL Project
• history of fever plus danger signs indicative of severe febrile illness / suspected severe malaria, according to local iCCM guidelines
• positive malaria test result by RDT or microscopy
• written informed consent from a parent or guardian

Exclusion criteria

• no current malaria infection
• mixed or mono-infection with a non-P. falciparum species known prior to sample collection
• no permanent residence in project area