Malaria Control


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Malaria Control

  1. 1. Objective Familiarisation with malaria and the most relevant vector control tools and strategies: ITNs and IRS. Program Day 1 Intro malaria Prevention tools; pro’s and con’s; selecting the most appropriate tool Exercise Day 2 IRS theory IRS practice
  2. 2. <ul><ul><li>300-500 million clinical cases per year </li></ul></ul><ul><ul><li>1 million deaths per year </li></ul></ul><ul><ul><li>2/3 rd deaths are children < 5 years </li></ul></ul><ul><ul><li>90% of deaths in Sub-Saharan Africa </li></ul></ul><ul><ul><li>Accounts for 10-13% of maternal deaths </li></ul></ul><ul><ul><li>In many parts of Africa, children experience at least 3 life-threatening malaria infections by the age of one </li></ul></ul>The Burden of Malaria
  3. 4. <ul><li>Linked to mosquito presence and survival (av. 30 day) vs. pathogen development (9 days in 30ºC; 20 days 20ºC) </li></ul><ul><li>Temperature (>16ºC) below 2000 metres </li></ul><ul><li>Humid environment, often seasonal </li></ul>Environment for Malaria
  4. 5. <ul><li>Malaria can be endemic: continuous transmission severe malaria mostly in children, pregnant women (unborn child), immuno-compromised </li></ul><ul><li>Malaria can be epidemic: occur in outbreaks severe malaria in all age-groups </li></ul>Endemic vs epidemic
  5. 6. <ul><li>Immunity is acquired through repeated infection </li></ul><ul><li>Asymptomatic infections common </li></ul><ul><li>When regularly exposed: people create immunity -> vulnerable children, pregnant women </li></ul><ul><li>Immunity of humans is short-lived </li></ul><ul><li>Mosquitoes are infected for life </li></ul>Immunity
  6. 7. Where would you expect a high risk of malaria outbreaks? <ul><li>Susceptible population entering endemic area </li></ul><ul><li>Infected population entering non-endemic area </li></ul><ul><li>Reduced resistance in population </li></ul><ul><li>No access to effective treatment </li></ul><ul><li>Change in environment/ climate </li></ul>
  7. 8. Malaria: The Big Picture China N.America & Europe Africa World 1900 1930 1950 1970 1990 2000 0.1 1.0 3.0 2.0 Annual Deaths from Malaria (millions) Central & S.America Asia
  8. 9. Stable War Refugees 1 in 3 of the worlds annual malaria deaths occurs in Africa in countries affected by conflict
  9. 10. Malaria Transmission
  10. 11. <ul><li>Aedes spp. Dengue, yellow fever & filariasis </li></ul><ul><li>Culex spp. filariasis & nuisance </li></ul>Malaria Transmission <ul><li>~ 3000 mosquito spp. </li></ul><ul><li>~ 400 Anopheles spp </li></ul><ul><li>~ 60 transmit malaria </li></ul><ul><li>Principal African malaria vector is Anopheles gambiae </li></ul>Mosquito Host Susceptible person
  11. 12. Malaria Control Mosquito Host Susceptible person Cure hosts: - treatment Isolate host - bednet <ul><li>Control mosquito </li></ul><ul><li>insecticidal bednet </li></ul><ul><li>indoor residual spraying </li></ul><ul><li>other… </li></ul><ul><li>Isolate mosquito </li></ul><ul><li>bednet </li></ul><ul><li>building </li></ul><ul><li>repellant </li></ul><ul><li>prophylaxis </li></ul>
  12. 13. <ul><li>Malaria control: “measures designed to reduce morbidity and mortality due to malaria”  prevention, surveillance and case management </li></ul><ul><li>Malaria prevention: “measures designed to sharply reduce, or stop, people from becoming infected” </li></ul><ul><ul><li> Vector Control (IRS, fogging, larvaciding), personal protection (ITN, repellents), prophylaxis and IPT </li></ul></ul><ul><li>Vector control: “measures designed to control (= reduce) the disease transmitting vector” </li></ul>Terminology
  13. 14. Malaria Prevention <ul><li>Chemoprophylaxis daily/weekly, IPT </li></ul><ul><li>Home use products coils, aerosols, repellents </li></ul><ul><li>(LL)ITN </li></ul><ul><li>ITM tarpolin, tents, blankets, chaddars, wallpaper, paint, cattle </li></ul><ul><li>IRS </li></ul><ul><li>Fogging / aerosol spraying </li></ul><ul><li>Larviciding </li></ul><ul><li>Environmental control </li></ul>
  14. 15. <ul><li>Indoor Residual Spraying (IRS) </li></ul><ul><li>(Long Lasting) Insecticide Treated Nets ((LL)ITN) </li></ul>Most effective/efficient control methods in emergencies
  15. 16. <ul><li>Provides physical barrier, repellent and kills vectors (mosquitoes will normally not ‘drop dead’ directly, may need up to 30 minutes before you see effect) </li></ul>(LL)ITNs <ul><li>Protects against other diseases </li></ul><ul><li>Untreated nets: little impact </li></ul>
  16. 17. <ul><li>Can be used indoors an outdoors </li></ul><ul><li>Can be taken/set up on the move </li></ul><ul><li>Can be looted </li></ul><ul><li>Only appropriate where people are used to using them or where extensive sensitisation component is feasible </li></ul>(LL)ITNs
  17. 18. <ul><li>Residual effect up to 5 years (20 washes) </li></ul><ul><li>Re-treatment < 5% </li></ul><ul><li>Pre-treated nets unreliable </li></ul><ul><li>Re-treatment of coloured conventional nets </li></ul><ul><li>No storage & handling of hazardous chemicals </li></ul>LLITNs
  18. 19. LLITNs Source: WHOPES updated: December 2007
  19. 20. <ul><ul><ul><ul><ul><li>Olyset Permanet 2.0 </li></ul></ul></ul></ul></ul><ul><li>Insecticide permethrin deltamethrin </li></ul><ul><li>Material/fibre polyethylene polyester </li></ul><ul><li>Deniers 150 75 and 100 </li></ul><ul><li>Mesh 50 and 100 156 </li></ul><ul><li>Size </li></ul><ul><li>Shape </li></ul><ul><li>Colour </li></ul>LLITNs
  20. 21. ITN and/or IRS What do you need to know in order to select the right tools at the right time in an emergency situation?
  21. 22. What do you need to know in order to select the right tools at the right time in an emergency situation? <ul><li>Is there malaria transmission in the area? </li></ul><ul><li>Feasibility access, security, HR, funding, logistics </li></ul><ul><li>Malaria epidemiology perennial or seasonal transmission, endemic or epidemic </li></ul><ul><li>Vector behaviour indoor/outdoor feeding, indoor/outdoor resting, day/dusk/night feeding, insecticide resistance </li></ul><ul><li>‘ Demography’ composition, vulnerable groups, mobility, sleeping arrangements, bed/hut size, shelter material </li></ul><ul><li>Population’s KAP Knowledge, attitude & practices </li></ul>