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Malaria diagnosis Removing the blindfold

Malaria diagnosis Removing the blindfold. David Bell WHO – Global Malaria Programme LSHTM April 2010. Liu Bolin. Magnitude of over-diagnosis /over-treatment. Systematic review: 24 studies conducted between 1989 and 2005 in 15 different African countries including 15’331 patients

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Malaria diagnosis Removing the blindfold

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  1. Malaria diagnosisRemoving the blindfold David Bell WHO – Global Malaria Programme LSHTM April 2010

  2. Liu Bolin

  3. 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

  4. Amexo M, Tolhurst R, Barnish G, Bates I. Malaria Misdiagnosis: effects on the poor and vulnerable. Lancet 2004; 364:1896-98

  5. 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%) The importance of distinguishing malaria from other causes of fever Admissions for ‘malaria’ in 10 hospitals in NE Tanzania. High mortality for wrongly-diagnosed fever Reyburn H et al. BMJ 2004

  6. Diagnostic contrasts: Malaria and other diseases • ? TB: Treat if disease is confirmed • ? HIV: Treat if disease is confirmed • ? Influenza: Treat if disease is confirmed • ? Pneumonia: Treat if disease is confirmed (signs) • ? Typhus: Treat if disease is confirmed • ? ……… • ? Malaria: Guess, treat, and hope ….

  7. 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.

  8. Conventional microscopy for malaria detection

  9. Malaria Rapid Diagnostic Tests (RDTs)

  10. Accurate malaria diagnosis can now be accessible to all. Courtesy: Malaria Consortium

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

  12. 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

  13. Scale up of RDTs and ACTs in India Millions of kits/doses Source: personal communication: NMCP India, 2008

  14. ACT 12 month health worker follow-up Zambia 2007-8 Zambia NMCC, Mal Consortium, WHO, FIND, URC

  15. Challenges to ensuring access to accurate RDT-based diagnosis • Sensitivity20% to 99% in published studies • Stability • Recommended storage temperature often inappropriate for rural health clinic in tropics (e.g. <30°C) • User safety • Blood safety (gloves, sharps disposal, HIV risk) • Programmatic • Managing negative results (non-malaria fever patients) • Logistics • Monitoring • Treatment ignoring diagnostic results

  16. Product Testing Rnd 1 (2008) 41 products Rnd 2 (2009) 27 products Rnd 3 (2010): 47 products WHO, FIND, TDR, US CDC

  17. Lot Testing Collection and testing site Specimen characterization Regional lot-testing site HTD CDC DMR UCAD UL IPB RITM IPC EHNRI CIDEIM KEMRI IHRDC IMT IPM AMI 2006: 41 lots 2007: 81 lots 2008: 167 lots 2009: 196 lots (?15% of public sector procurement) 2010: +++

  18. Community-level monitoring of RDT quality Now: Compare routinely with microscopy (often difficult) Future: Positive Control Wells Under development by FIND, WHO, and partners Field implementation trials planned Antigen types 1 2 3 4 5 6 7 8 9 10 Antigen concentration Water added Contents placed on RDT Dried antigen Future lot-testing panels

  19. Taking heath-worker training seriously - Zambia Suite of products: Job-aid Training manual Photographic result guide Proficiency tests www.wpro.who.int/sites/rdt, Zambia MoH, URC, WHO, TDR, FIND, Malaria Consortium

  20. Managing fever, not malaria Febrile patient Anti-malarial medicine Can of worms… RDT / microscopy ~20% ~80% Malaria Non-malaria Severe symptoms Not severe Anti-malarial medicine Manage in community ? review ? Antibiotics ? Other Refer

  21. Minimum standard for funding a diagnostic programme? Transport and storage Training, drugs / supplies for non-malarial fever Community education Training and supervision Monitoring accuracy in field Lot-testing and laboratory monitoring Procurement of gloves, sharps disposal containers etc Procurement of RDTs Need to build programmes, not just fund procurement

  22. Where do we go after we are successful?… a larger can of worms… Successful intervention 10 cases per month. Malaria now down from 1st to 16th district health priority….other disease priorities are more urgent But the mosquitoes and the people are still there… We have the tools to identify and manage malaria as a common disease We need new tools and strategies to manage malaria as a rare disease

  23. New diagnostic strategies to achieve and maintain eliminationFinding and eliminating hidden parasite reservoirs Serology Screen large populations for signs of recent malaria transmission Malaria LAMP Detects 1 parasite/µL Potential for district / clinic level use Find and treat malaria ‘carriers’

  24. Current maps of malaria incidence WHO 2009 www.map.ox.ac.uk2009

  25. Possible future for malaria?? Polio case numbers 1988: 350,0001999: 7,1412000: 2,9792001: 483

  26. Summary: Parasite-based diagnosis and ACT If no parasite-based diagnosis: • Most recipients of ACT will not have malaria • Patients with non-malarial febrile illness will receive wrong or late treatment • Malaria incidence rates will be unavailable • (Poor resource allocation, poor planning, no elimination) However, delaying ACT raises malaria mortality: • Improving access to ACT is essential, should not be delayed Diagnosis needs to catch up to treatment.

  27. Are we victims of a history? If malaria arose for the first time today…. would we consider routinely sending children home with 3 days of anti-malarial drugs when we know they probably have another, potentially fatal, illness? Thank you

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