Malaria and its conquering

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Malaria and its conquering

• Joel G. Breman, MD, DTPH
• Fogarty International Center
• National Institutes of Health
• Tropical Infectious Diseases Workshop
• Oswaldo Cruz Foundation (FIOCRUZ)
• Rio de Janeiro, Brazil
• 28 April1 May 2003

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Conquering Malaria

• Ecology and burden
• Interventions
• Successes
• Economics
• Research questions
• Controversies

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Ecology and Burden
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Malaria and Ecology and Burden

• Intrinsic and Extrinsic Factors

Control and prevention measures
Social, behavioral, economic and political
factors
Human
Parasite
Mosquito
Environmental conditions
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Malaria Ecology and BurdenClinical Manifestations
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Global distribution of Plasmodium vivax
maximum distribution 19th century (pink)
late 20th century
(purple)
Mendis K, Sina B J, Marchesini P, Carter R (2001)
The neglected burden of P.vivax malaria. American
Journal of Tropical Medicine and Hygiene 64
Supplement titled "The Intolerable Burden of
Malaria A New Look at the Numbers" 1-106.
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MARA/ARMA Model of Malaria Transmission, 2003
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Deaths and Malaria-related Deaths (1000s), 2000
Population All deaths () Malaria Deaths () Malaria/ total ()
World 6,122,210 56,554 1,124 2.0
Africa 655,476 10,681 (18.9) 963 (85.7) 9.0
Americas 837,967 5,911 (10.5) 1 (-) 0.02
East Med. 493,091 4,156 (7.3) 55 (4.9) 1.3
Europe 874,178 9,703 (17.2) 0 -
SE Asia 1,559,810 14,467 (25.6) 95 (8.5) 0.7
West Pacific 1,701,689 11,636 (20.6) 10 (0.9) 0
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Disabilityadjusted Life Years (DALYs,
1000s),All Cause and Malaria-related, 2002
Population DALYs from all deaths () DALYs from malaria deaths () DALYs from malaria /total ()
World 6,122,210 1,467,257 42,280 2.9
Africa 655,476 357,884 (24.4) 36,012 (85.2) 10.1
Americas 837,967 145,217 (9.9) 108 (0.2) 0.07
East Med. 493,091 136,221 (9.3) 2,050 (4.8) 1.5
Europe 874,178 151,223 (10.3) 20 (0.04) 0.01
SE Asia 1,559,810 418,844 (28.5) 3,680 (8.7) 0.9
West Pacific 1,701,689 257,868 (17.6) 409 (1.0) 0.2
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Estimated World and Regional Malaria Deaths,
1952-1999
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Percentage of Deaths from Disease Occurring Among
the Poorest 20 of Global Population
Deaths

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Interventions
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Estimated Cost of Malaria Control in an Endemic
Area One Million People, One Round of Residual
House Spraying
Insecticide One application (tons) Price/ton Total cost Cost per capita
DDT 147 3,950 580,650 0.58
Malathion 220 4,300 946,000 0.95
Deltamethrin 110 20,000 2,200,000 2.20
Pyrimiphos-methyl 220 16,000 3,520,000 3.52
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Estimated Cost of Malaria Control One Million
People, One Full-dose Treatment, 1999
Drug Tablets in millions (dose) Price/ 1000 tabs Total cost Cost per capita
Chloroquine (3 days) 11.25 (100 mg) 6.05 68,063 0.08
Sulfadoxine-pyrimethamine (one dose) 2.5 (500 mgS/ 25 mgP) 47.00 117,500 0.12
Quinine (7 d) 31.5 (300 mg) 41.25 1,299,375 1.30
Artesunate (5 d) 13.5 (50 mg) 365.00 4,927,500 4.93
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Successes
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Successes

• 1899, (large scale) demonstration of successful
  Anopheline control in Cuba antilarval and adult
  measures (large-scale)
• 18991914, multiple demonstrations of control by
  reduction of Anopheline larvae and adults
• 1899, Sierra Leone (antilarval) Cuba
  (large-scale) Malaysia (antilarval)
• 19041914, Panama Canal Zone control by
  larviciding, large-scale environmental
  modification
• 1927, elimination of A. albimanus in Barbados
  (first area-wide success with invading species)

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Successes (2)

• 1935-1939, large-scale control by pyrethrum
  spraying in South Africa, Netherlands and India
• 1939-1957
• 1939-1940, Elimination of invading A.gambiae from
  Brazil
• 1942-1945, A.gambiae eliminated from northern
  Egypt
• 1946-1957, Interruption of transmission by
  anti-mosquito measures in Cyprus, Sandinia,
  Guyana, Venezuela and Greece indoor residual
  spraying with DDT, a major strategy

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Successes (3)

• 1987-2003
• Multiple projects and programs using
  insecticide-impregnated bed nets demonstrate
  overall mortality reduction and decrease in
  several malaria indices

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Interventions, Control and Economics
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Type of ControlVector Control

• Environmental modification (urban)
• Chemical and biological larvicides
• Indoor residual insecticide spraying
• Outdoor residual insecticide spraying
• costly and effective

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Type of ControlPersonal protection (2)

• Insecticideimpregnated materials
• nets, curtains, clothing
• House screening
• House location
• Repellents
• Fumigants
• Shown cost effective for low-income countries

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Type of ControlAntiplasmodial (3)

• Patient management early diagnosis, treatment,
  referral, education
• Chemoprophylaxis
• Intermittent treatment (pregnancy)
• Radical therapy for relapses (P.vivax, P.ovale)
• cost effective

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Type of ControlSocial Action

• Mobilization of individual, family, community
• Health education
• Management Effectiveness
• Health systems effectiveness (quality),
  efficiency
• Leadership, planning, policies, strategies,
  tactics
• Surveillance
• Monitoring and evaluation

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Research Questions
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Research Agenda

• Pathogenesis
• Drug development
• Vaccine development
• Diagnostics
• Clinical and community-based trials
• Entomology

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Research Agenda (2)

• Clinical issues
• anemia
• neurologic and cognition
• pregnancy-related
• Health services delivery
• Social, legal, ethical

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Controversies
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Controversies

• Drugs
• Combination artemisinin-based compounds for
  treatment
• Chemoprophylaxis for high risk persons
• Burden
• Malaria as a cause or risk-factor
  (co-morbidity)
• Cognition and developmental issues

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Controversies (2)

• Transmission
• Cost-effective vector control approaches in urban
  and rural areas
• Impregnated materials, how to improve and make
  the social standard
• Basic research
• Immunologic, genetic

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Malaria, Annual WHO Estimates, 1997
Region Population at risk (1000s) Total Cases () (1000s) P. Falciparum () (1000s) P.vivax () (1000s)
SE Asia, Western Pacific 1,284,000 86,401 44,400 42,006
Eastern Mediterranean 64,600 14,539 2,883 11,656
Central America/ Caribbean 64,200 3,676 580 3,096
South America 23,500 11,325 3,347 7,978
Central Asia/ Cancasus 8,480 167 0 167
World total outside Africa 1,444,780 116,334 51,211 65,124
Africa 550,000 300,000 Most of total 6-15,000
Imported malaria² 1,590,000 33 11 22
Total ³
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100
Plasmodium vivax
10


1
0.000
0.01
0.1
1.0
10.0
0.001
Total Annual Malaria Incidence Rate ()

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100
Plasmodium vivax
10


1
0.000
0.01
0.1
1.0
10.0
0.001