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Presentation for in-house capacity-building session at Abuja Clinics, 2003. The material is out-dated but uploaded for the record.

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  1. 1. MALARIA: New Trendsin Treatment/Vaccination Presenter – Dr Victor Ordu
  2. 2. Malaria (it. “bad air”) is a disease caused byinfection with parasites of the genusPlasmodium.First described by HippocratesP. falciparum, P. malariae, P. ovale and P. vivaxcause disease in humans.Falciparum malaria accounts for majority ofcomplications and deaths.It is transmitted from person-to-person by femaleanopheline mosquitoes during blood meals
  3. 3. DistributionA disease of thetropics500 millioncases annually1 million deathsevery year –90% of these inSub-SaharanAfrica (SSA)Most deaths areamong childrenaged 1 – 59months
  4. 4. Transmissionoccurs in 2forms –endemic andepidemic Endemic – young children and pregnant women are worst hit Epidemic – population usually non- immune & all age groups affected
  5. 5. Malaria ControlFirst successful efforts by the ancientRomans – drainage of marshlandsCinchona bark used by Peruvians in the1600sDiscovery of malaria agent by AlphonseLaveran in 1879Malaria transmission elucidated byRonald Ross (1897)DDT discovered by Paul Muller in 1942;first used in Italy in 1944
  6. 6. Failure of malaria eradication efforts of the1950s-60s gave way to an era of maintenance ofmalaria-free zoneControl in N. Africa largely successful b/c ofpredominance of P.vivax infections. Surveillanceefforts continue in these countriesIn SSA resilience of main vector (A. gambiae),dearth of resources & complacency led tofailure.In SSA, data shows rise in malaria relateddeaths in the 1990s due to drug resistance,breakdown of control programmes, climate &environmental change, exposure of non-immunepopns and HIV/AIDS
  7. 7. Rolling Malaria BackWHO initiated Roll Back Malaria campaignin 1998 to coordinate a global effort atreducing malaria-related morbidity andmortality.African Heads-of-State pledge to fightmalaria at Abuja Summit in 2000.Private sector involvementGlobal Fund to Fight AIDS, Tuberculosis &Malaria
  8. 8. New Strategies and TechnologiesInsecticide-Treated Nets (ITNs)Intermittent Preventive Treatment (IPT)Artemisinin-based Combination Therapy (ACTs)Home-based management of fever (HBMF)Malaria Early Warning Systems (MEWS)Vaccine developmentMalaria Genomics
  9. 9. Insecticide-Treated Nets (ITNs)Introduced in the mid 1980sPyrethroids in use – deltamethrin, labda-cyalothrinProbably the most effective preventive measure inuse15% U5s slept under nets; 2% under ITNs (AMR, 2003)
  10. 10. Evidence of some studies show: Reduced U5 mortality by 20% Reduced Clinical falciparum dx by 50% Reduced maternal morbidityProblems of cost; need for relaxation of taxesand tariffsProgress – Long Lasting Insecticide treated Nets(LLINS) can last for 4 – 5 years & resist washingreduce exposure and environmentalcontamination
  11. 11. Intermittent Preventive Treatment (IPT)2 single-dose administrations of antimalarials attherapeutic doses during the routine antenatalvisitsSulfadoxine-pyrimethamine (SP) is drug ofchoice (in areas where there is no resistance)Studies so far indicate a decreased proportion ofwomen with anaemia and placental infection atdeliveryComplemented by ITNs & effective casemanagement
  12. 12. Artemisinin-based Combination Therapy (ACTs)Monotherapies are failing!Many countries have changed drug policies infavour of combination therapies especially whereCQ resistance ehas been documentedACTs are currently recommended (WHO 2004)due to: Documented efficacy Likely delay in devt of resistant strainsCostly and hence require donor inputs CQ – USD 0.13 SP – USD 0.14 ACTs – USD 1-3 (for adult outpatient treatments)
  13. 13. Favoured combinations Atrmether-lumefantrine (Coartem) Artesunate-amodiaquine Artesunate-SPNon artemisinin based combination are alsoacceptable e.g. amodiaquine- SP,
  14. 14. Malaria Early Warning Systems (MEWS)Used to predict and improve response tomalaria epidemicsLargely employed in the SADC bloc and thenorthern fringe of the malaria zoneInvolves monitoring vulnerability andtransmission risk factors such as: Seasonal climate forecasts Rainfall estimates Population movements Entomological indices
  15. 15. MEWS often require high degree oftechnical expertise and inter-sectoralcollaborationVery helpful in the event of complexemergencies such as natural distasters orcivil strife which account for 30% ofmalaria deaths (malaria is No.1 killer incomplex emergencies in SSA)
  16. 16. Malaria GenomicsRecent advances Human genome elucidated Genomes of A. gambiae and P. falciparum (Oct 2002) P. yoelli – rodent malaria. Provides a model for studies
  17. 17. Possible uses Study of mechanisms of drug/insecticide resistance Development of vaccines Elucidation of mechanisms of immune evasion Genetic engineering of vectors Discovery of drug targets
  18. 18. Malaria Vaccine ResearchIdeal vaccine – multispecies, multistrain4 general vaccine candidates undergoingR&D Pre-erythrocytic (Sporozoite & liver stage) – e.g. CS, LSAs Asexual blood stage – e.g. MSPs, AMA-1 Transmission-blocking – Pfs 25 & 28, Pvs 25 Anti-disease – Anti-GPIStill undergoing clinical trials
  19. 19. Thank you