Malaria

1
Malaria

• from prehistoric Africa
• to
• a global burden today

2
Malaria - global burden

• Worldwide prevalence estimated to be in the order
  of 300-500 million clinical cases per year
• Mortality due to malaria estimated to between 1
  and 2 million per year
• 90 of deaths occur in sub-Saharan Africa
• High risk groups include young children, women
  during pregnancy, non-immune travelers, refugees
  and migrant labors
• Millions are affected by severe aneamia and low
  birth weight due to malaria

3
Malaria - impact

• Africas GDP today would be 32 greater if
  malaria had been eliminated 35 years ago
• Malaria-afflicted families on average can only
  harvest 40 of the crops harvested by healthy
  families
• Workers suffering from malaria can be
  incapacitated for at least 5 days

4
Malaria

• The four different species of human malaria
  parasites
• The life cycle

5
Malaria - endemicity

• Hypoendemicity(very unstable)
• Mesoendemicity
• Hyperendemicity
• Holoendemicity (very stable)

6
Malaria - the vector

• Life cycle
• Breeding preference

7
Malaria - the vector

• What makes a good vector
• high infectivity
• high preference for human blood
• long-lived
• high density of vectors in relation to man
• high preference for indoor biting
• preference for breeding close to human
  settlements
• high man biting rate
• biting coincides with human exposure

8
Malaria

• different approaches to control

9
Objectives for malaria control programs

• To reduce mortality and severe illness from
  malaria in high endemic areas (e.g. Africa South
  of Sahara)
• To reduce overall morbidity and mortality in
  areas of low transmission (e.g. South Asia)
• To reduce risk of epidemics in areas of low
  transmission (e.g. South and South-East Asia)

10
Reducing severe morbidity and mortality

• Reducing the number of infective mosquito bites
• Early diagnosis and treatment with effective drugs

11
Malaria - challenges for control

• Health systems failure
• Mosquito insecticide resistance
• Parasite drug resistance
• Population movements and refugees
• Unplanned developments
• Environmental changes
• Lack of research and drug development

12
Malaria - breaking the cycle

• How?

13
Malaria - breaking the cycle

• Protect people from mosquito bites
• reduce no of vector mosquitoes
• reduce vector survival
• reduce no of people with circulating gametocytes

14
Residual spraying

• Why?
• How?
• Advantages?
• Disadvantages?

15
Malaria - Residual Spraying

• What would determine the effectiveness and
  sustainability of a residual spraying program?

16
Malaria - bed nets

• Why?
• How?
• Advantages?
• Disadvantages?

17
Malaria - bed nets

• What would determine the effectiveness and
  sustainability of a bed net program?

18
Malaria - early diagnosis and treatment

• Discuss what may result in people delaying
  seeking treatment?
• What may determine people choice of treatment for
  malaria
• Discuss advantages and disadvantages of self
  treatment for malaria