Apparently last Sunday was Dunk Malaria day. Obviously I’m late but better late than never, right? Actually below is everything a Biology University of Cambridge A-level student should know about Malaria.
Malaria can be caused by a variety of the protoctist Plasmodium, namely Falciparum, Vivax, Ovale and Malariae. The protoctist is transmitted by an insect vector: the female Anopheles mosquito.The annual incidence worldwide is reported to be 300 million and the annual mortality rate worldwide is estimated between 1.5 to 2.7 million. Malaria occurs mainly in tropical and subtropical countries of the world, where the conditions for mosquitoes to breed is more favourable than elsewhere on the planet.
The female Anopheles mosquito feeds on human blood to obtain the necessary proteins of their diet. If the female Anopheles mosquito bites a person who suffers from malaria, and therefore carries Plasmodium in his blood, the mosquito will take up some Plasmodium gametes. The gametes fuse (sexual reproduction) inside the mosquito’s gut to form the germs themselves. These move into the mosquito’s salivary gland.
During another blood meal, when the mosquito bites another person, the salivary gland secretes an anticoagulant, just like it does all the time. This is done so as to prevent clotting of the blood in the mosquito’s mouthparts. However while secreting the anticoagulant, the Plasmodium germs are also injected into the bloodstream.
The Plasmodium germs, when in the body, move to the liver cells where they reproduce asexually. The consequent amount of germs produced finally leave the liver cells and migrate into red blood cells. By fission, the Plasmodium again reproduces asexually inside the red blood cells until those can no longer hold them inside its membrane. The red blood cells explode releasing a fluffy of Plasmodium together with their secreted toxins into the blood.
- Shivering and clattering of teeth occurs during the cold stage.
- 40oC body temperature and increased heart rate and breathing rates, usually accompanied by headache and nausea. This is the hot stage.
- Heavy sweating cools the body down during the sweating stage.
- Fever occurs again at different intervals, depending on the species of Plasmodium.
- Anaemia, liver damage and swollen spleen are all possible.
By making use of a proper drainage system and insecticides, the vector may completely be eradicated. Drainage ensures that there are less breeding grounds for the mosquitoes while insectides simply exterminate them.
Vaccines can also be used although because of the different species of Plasmodium, there are some difficulties in producing efficient ones.
Precautions to avoid being bitten by mosquitoes should be undertaken. These include making use of the appropriate equipments (mosquito nets) and propellants.
That’s exactly what I handed over for my assignment on Infectious diseases for Biology, earlier this month. I got top marks for this one.