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lecture 4

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- 1/5 of the world population is at risk of malaria (over 100 endemic countries)
- 300-500 million cases of malaria per year
1 million malaria related deaths (>90% in Africa)
most malaria forms do not lead to death
disability from severe forms of the disease (to the brain, coma)
parasite: plasmodium falciparum/vivax/ovale/malariae
vector: female Anopheles mosquito
- develops within mosquitoes Æ bites Æ passes parasite
- sporozoites into liver, multiplies, moves into blood, attacks red blood cells
* acute disease Æ non-severe acute febrile disease Æ cerebral malaria Æ death
* chronic disease [requires blood transfusions - which are often infected]
1. Æ chronic/recurrent asymptomatic infection Æ anemia Æ development disorders
transfusions Æ death
2. Æ infection during pregnancy Æ placental malaria & anemia Æ low birth weight Æ
increased infant mortality
- impairs physical/mental development in children
- DDT, temperature declines, filling marshes
endemicity: intensity of malaria transmission in a location
- parasite rate
- holoendemic (PR >=75%)
- hyperendemic (PR >=50-74.9%)
- mesoendemic (PR >=25-49.9%)
- hypoendemic (PR >= )
- ~50 billion infections in Africa
- ~1/100 infections leads to clinical illness
- ~1/50 results in the severe form of disease
- ~1/5 of severe malaria leads to death (1 - 2 million a year)
Sub-Saharan Africa
- 20% of all childhood deaths (under 5)
- 975 000 children (< 5), 100 000 women estimated to die each year
- 20.3% - leading death of all children in the African region
- can be cured with right drugs
* cleared land = more prone to formation of puddles Æ formation of mosquitoes
* forest cover = lower temperatures
* higher temperatures = increase pace of mosquito development, increasing frequency of
blood feeding
- clinical consequences vary -- asymptomatic or life-threatening
- risk of illness and death is strongly influenced by semi-immunity developed from re-
-- varies on period of time living within the area
- high risk groups (young children, pregnant women, HIV-infected)
- malaria is responsible for a "growth penalty" - up to 1.3% per year
- leads to loss of productivity due to illness, school absenteeism, permanent
neurological/other damage
- loses more than US $12 billion annually - restrains investment & economic growth
- less people available to work, unable to perform well
Africa: - plasmodium falciparum
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