Thursday, 30 May 2013

AS Biology F212: Malaria

Malaria is caused by the protoctist Plasmodium. The vector for malaria is female Anopheles mosquitoes

Transmission

  • Mosquitoes takes a blood meal from an infect person who has the parasites in their blood
  • Then they feed on an uninfected person
  • The parasites are present in the saliva of the mosquito
  • Causes of illness
    • red blood cells break open and release parasites into the bloodstream
    • the person then has symptoms such as chills, fever and headache.
    • then the person starts sweating and their body temperature falls
    • cycle of symptoms repeats every 48 to 72 hours, following the life cycle of the parasites
    • each cycle worsens the person's anaemia or lack of red blood cells
    • less and less oxygen reaches the brain and other organs
    • so the symptoms are:
      • fever, anaemia, headaches, shivering, sweating, nausea
Distribution
  • Fighting malaria
    • best method of prevention is to get rid of the mosquitoes
    • either use insecticides or get rid of breeding grounds
    • some success with this method - malaria eliminated from some parts of the world
  • Difficulties
      • Mosquito - can become resistant to insecticides and chemicals used to contorl
        • they breed very quickly
        • breeds in the smallest bodies of water
        • especially in rainy seasons of tropics
        • difficult to drain water to prevent egg laying
        • increasing areas with global climate change
      • Plasmodium
        • drugs are used to fight it but they can also ecome resistance to drugs
        • people do not take the drugs for a long period of time so it comes back
        • different strains (4 specials)
        • different stages to life cycle
        • complex organism so difficult to target drugs
        • inside the RBC and liver cells - hard to get them as they are inside delicate cells
        • No vaccine

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