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Improving Malaria Diagnosis: From Chaos to Order for Elimination

Learn about the importance of prompt parasitological confirmation for malaria diagnosis before treatment, the challenges in implementing comprehensive RDT-based diagnosis, and the need to build structured diagnostics programs. Explore innovative planning, training, and collaborations to improve malaria diagnosis and contribute to elimination efforts.

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Improving Malaria Diagnosis: From Chaos to Order for Elimination

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  1. Malaria diagnosis: Moving from a mess to an ordered programme to a tool for eliminationThe All-Party Parliamentary Group on Malaria and Neglected Tropical Diseases (APPMG) David Bell FIND Nov 2009

  2. Malaria Diagnosis, WHO 2009 • Prompt parasitological confirmation by microscopy or alternatively by RDTs is recommended in all patients suspected of malaria before treatment is started. • Treatment solely on the basis of clinical suspicion should only be considered when a parasitological diagnosis is not accessible.

  3. Confirmation of diagnosis % confirmation of parasitaemia in suspected malaria cases World Malaria Report 2008

  4. Magnitude of over-diagnosis /over-treatment Systematic review: 24 studies conducted between 1989 and 2005 in 15 different African countries including 15’331 patients Proportion of malaria among fevers highly variable: 2% to 81% MEDIAN PR = 26% Before 2000 MEDIAN PR = 36% From 2000-2005 MEDIAN PR = 19% Courtesy of: V. D’Acremont, C. Lengeler, B. Genton, Philadelphia, November 2007

  5. Changing case managementManagement of febrile illness Febrile patient Anti-malarial medicine RDT / microscopy ~20% ~80% Malaria Non-malaria Severe symptoms Not severe Anti-malarial medicine Manage in community ? review ? Antibiotics ? Other Refer

  6. No criteria for severe disease n=12,643 (73%) 120 deaths (1%) Admissions for malaria n=17,313 Severe disease n=4670 (27%) Readable slide results n=4474 (95%) Expert microscopy positive n=2062 (46%) Expert microscopy negative n=2412 (54%) Dead n=142 (7%) Alive n=1920 (93%) Dead n=292 (12%) Alive n=2120 (88%) Can we ignore non-malarial fever? High mortality among patients admitted to hospital and incorrectly treated for malaria, 10 hospitals, NE Tanzania Reyburn H et al. BMJ 2006

  7. RDT impact, Zambia ACT Source: NMCC, Zambia MoH

  8. Senegal RDT implementation (% of RDT use by month in 2007 - 2008) Courtesy Babacar Faye and Senegal MoH

  9. Senegal Parasite prevalence of malaria-like fever cases RDT introduction Courtesy Babacar Faye and Senegal MoH

  10. Weekly Malaria Lab. Tests, 2008, Kabale District: Uganda Saving costs by treating only lab confirmed case! Uganda, RDT implementation Courtesy Uganda MoH, Uganda WHO office

  11. Scale up of RDTs and ACTs in India Millions of kits/doses

  12. Challenges to implementing comprehensive RDT-based diagnosis • Sensitivitye.g. 20% to 99% in published studies • Stability • Recommended storage temperature often inappropriate for rural health clinic in tropics (e.g. <35°C) • User safety • Blood safety (gloves, sharps disposal, HIV risk) • Programmatic • Managing negative results (non-malaria fever patients) • Logistics • Monitoring

  13. Building a structured diagnostics programme Should be integrated where possible with laboratory services for other diseases

  14. Selecting RDTs for procurement.WHO Product Testing Round 1: 2008-9 ALL 60+ Manufacturers ~200 products ISO13485:2003 35 Manufacturers 112 products Evaluated 2008 21 Manufacturers 41 products

  15. Selecting RDTs for procurement: WHO Product Testing 2008-9 Performance against 200 para/µL samples www.wpro.who.int/sites/rdt

  16. Lot Testing WHO-FIND Laboratory network Collection and testing site Specimen characterization Global specimen bank Regional lot-testing site HTD CDC DMR UCAD UL IPB RITM IPC EHNRI CIDEIM KEMRI IHRDC IMT IPM AMI • Why lot-test? • Lot-lot variation noted in most products • Ensure no damage during transport to country • Need to convince clinicians / users / regulatory authorities that tests are working 2006: 41 lots 2007: 81 lots 2008: 167 lots (?15% of public sector procurement)

  17. Innovative planning, infrastructure and training SMS-based disease and stock reporting Productive collaborations Programme management Standardized job-aids and training Logistics manuals

  18. Courtesy: Malaria Consortium

  19. Minimum standard for funding a programme? Transport and storage Training, drugs / supplies for non-malarial fever Community education • To have an impact, we need to: • Build programmes, not just fund procurement • Develop sustainable methods and in-country capacity Training and supervision Monitoring accuracy in field Lot-testing and laboratory monitoring Procurement of gloves, sharps disposal containers etc Procurement of RDTs

  20. Positive control wells Lot-testing / lot-release panels HRP2 variants 1 2 3 4 5 6 7 8 9 10 Water added Contents placed on RDT HRP2 concentration Dried antigen, HSA etc In the pipeline 2010-2011:Country based lot-testing, clinic-based QC testing Recombinant antigen-based testing panels for RDTs: • Moving control of quality control to national programmes, and health workers, in endemic countries • Harmonizing standards and RDT detection thresholds between developers, manufacturers and users

  21. Towards elimination: Detection of P. falciparum ‘reservoir’ Parasite density HRP2 concentration Average field microscopy Good RDT Expert microscopy PCR fever months Sampling visibility

  22. (-) (+) Interspecies variability (GC-2) (GC-2) (GC-2) (GC-1) (GC-1) (GC-3) LAMP: Moving molecular diagnosis from London to Livingstone Population screening and LAMP In areas with low-transmission, a large proportion of patients with malaria are likely to have less than the 100 p/ml detected by RDTs. Development underway of Loop-mediated isothermal DNA amplification (LAMP) that detects 1-6 parasites /l with minimal sample processing that requires no sophisticated equipment and can be read with the naked eye (FIND, HTD London, Eiken). Primers amplifying Plasmodium mitochondrial DNA

  23. Collect blood spots Punch into 96 well plates Heat Place in turbidimeter – Eiken is launching one that runs 96 tubes at a time in November Spin Pipet supernatant into reaction tubes Potential for high through-put LAMP-based screening

  24. Accurate diagnosis at community level: Effort and outcomes Rational use of anti-malarial drugs (e.g. ACT) • Save resources • Reduce pressure • to drug resistance Early recognition and management of other diseases Accurate malaria diagnosis • Reduce mortality • Assess impact • Enable planning • Guide elimination Know true malaria incidence Is it good enough to guess in Africa, when this is not acceptable elsewhere?

  25. Acknowledgements WHO FIND HTD, UK RITM, Philippines IP, Cambodia US CDC AMI, Australia MSF DMR, Myanmar IP, Madagascar IP, Central African Republic IHDRC, Tanzania KEMRI, Kenya EHNRI, Ethiopia Uni Lagos, Nigeria UCAD, Senegal CIDEIM, Colombia IMT, Peru Zambia NMCC Uganda MoH URC Malaria Consortium NBI, South Africa BMGF USAID/Asia USAID/Deliver AusAID Manufacturers

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