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New technologies and capacity strengthening could improve global antimalarial resistance surveillance: Review

10 April 2018

Global health officials could improve surveillance of antimalarial resistance by applying new technologies for conducting in vitro and molecular studies, and supporting national reference laboratories in malaria-endemic countries, a recently published review reports.

Published in Malaria Journal, the review assessed available surveillance tools for tracking antimalarial resistance, and described the level of method standardization – especially for in vitro and molecular studies — as lacking. Study authors said a range of emerging affordable and easy-to-use techniques, combined with improving endemic country access to standardized protocols, training and proficiency testing (PT), could improve and sustain global surveillance networks.

Researchers have made significant progress measuring antimalarial resistance in recent years, including efforts to track resistance in near real-time. However, identifying funding to sustain surveillance and networking activities in low- and middle-income countries (LMICs) remains a challenge.

Currently researchers can track resistance using three methods, often in combination: in vivo studies of malaria patients treated with antimalarials; in vitro studies of parasite samples combined with doses of antimalarials; and, molecular studies of parasite genetics to identify markers of resistance.

The study reviews the challenges and opportunities of the three approaches.

Researchers noted that in vitro and molecular studies require strong infrastructure and highly trained staff, which LMICs frequently lack. New approaches, including ELISA and SYBR green for in vitro studies, and nucleic acid lateral flow immunoassay (NALFIA) and Q-poc for molecular studies, could potentially help, they said.

“New tools to detect markers of antimalarial resistance could significantly improve the surveillance landscape, but they must be matched with appropriate external evaluation through proficiency testing to ensure data quality and standardisation, to give a comprehensive picture,” said study co-author Dr Didier Ménard, of Institut Pasteur.

In addition to highlighting new tools, the study strongly affirmed the role of networks to support reference laboratories and provide external quality assurance (EQA) to uphold the scientific validity of the research.

The review compiled efforts by surveillance networks, including the Amazon Network for the Surveillance of Antimalarial Drug Resistance (RAVREDA), the US President’s Malaria Initiative Antimalarial Resistance Monitoring in Africa (PARMA) and the WorldWide Antimalarial Resistance Network (WWARN), citing the difficulty such networks face in bringing diverse stakeholders, such as the National Malaria Control Programmes (NMCPs), under a common agenda, and in generating sustainable funding from donors. 

“Support for national and regional reference laboratories in malaria endemic countries, and for the proficiency testing schemes which reinforce the work of these laboratories, could help facilitate and sustain antimalarial drug resistance surveillance on a global level,” said Dr Xavier Ding, Malaria Team Lead, Malaria and Fever Program at FIND.

WWARN launched its PT programme in 2010 and serves more than 18 laboratories around the world. The programme sends ‘blind’ plasma samples containing an unknown antimalarial drug to participating labs which must then identify the correct drug and measure the concentration. WWARN evaluates the results.

WWARN’s PT service is part of its External Quality Assurance (EQA) Programme, which provides reference materials – such as pre-weighted samples of antimalarial drugs and common drug metabolites – to more than 60 participating laboratories free of charge. WWARN is the only designated provider of these external quality control services for antimalarials worldwide.

References:

Nsanzabana C, Djalle D, Guérin P, Ménard D, González I, ‘Tools for surveillance of anti-malarial drug resistance: an assessment of the current landscape,’ Malaria Journal, 2018, Volume 17, Number 1, Page 1; DOI: 10.1186/s12936-018-2185-9