MALARIA

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MALARIA
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What is it?

• Disease transmitted by the bite of mosquito
  infected with the protist Plasmodium.

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What are the symptoms?

• Early stage
• Flu-like (high fever,chills, muscle pain)
• Progressive stage
• Heart, lung, kidney or brain damage
• Death

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How do people get infected?

• Bitten by the Anopheles mosquito
• Plasmodium life cycle

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Where is malaria found?

• Tropical Africa, Asia, Central and South America
• Poor sanitation contributes to high cases

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How to avoid malaria?

• Anti-malarial drugs before, during, and after
  travel to an area where malaria is present.
• Genetic resistance . . . ?

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Sickle cell Anemia

• Defective hemoglobin causes red blood cells to be
  shaped like a sickle (half moon)
• Abnormal red blood cells block blood vessels

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Sickle Cell Anemia

• Codominance
• Both alleles are fully expressed.
• Alleles
• R round-shaped
• R sickle-shaped
• Genotypes
• RR all round (no anemia)
• RR some sickle (no serious effect)
• RR sickle cells anemia

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Human Genetics

• R allele is common among Africans Why?
• Provides immunity to malaria
• Sickled red blood cells are deficient in
  potassium needed for Plasmodium
• What would be the best genotype to have in the
  tropical region of the world?

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Parasitic Relationship

• Parasite Plasmodium
• Host human
• Vector transmits the disease
• Mosquito
• EACH ARE INFLUENCING THE EVOLUTION OF ONE
  ANOTHER!

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Mosquito Evolution

1. Humans apply pesticides (DDT)
2. Most mosquitoes die
3. The survivors are genetically immune to the
   toxin.
4. Survivors pass genetic immunity to offspring
5. Soon entire population has evolved immunity!

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Plasmodium Evolution

1. Humans take anti-malarial drugs
2. Most plasmodium die
3. The survivors are genetically immune to the
   toxin. . . .(evolution)

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Human Evolution

• Majority of population of tropical zone are
  immune to malaria. How?
• Mutations in hemoglobin

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