A Crash Course in Malaria

“By the afternoon, even as the population of parasites in Duke’s body continued to ebb, the speckling of his eyeballs multiplied. That evening, suddenly, Duke stopped breathing. Taylor’s team rushed to his side. His heart thrummed an even, loud rhythm. But one by one his organs failed.”

If you live in a country where malaria isn’t endemic, chances are you have no idea what it’s like to live in the midst of this disease. If you don’t know anything, who could blame you for not caring as much as you should? This post will give you a crash course in malaria: what causes it, how you catch it, and what it does to your body.

Of the five different species of parasites from the Plasmodium genus that cause malaria, the ones that cause the most damage are P. falciparum and P. vivax. Falciparum is more deadly, and more prevalent in sub-Saharan Africa and Oceania; vivax in South-East Asia and South/Central America.

You can’t get malaria from any old mosquito bite: the parasite is only carried by around 60 species of mosquitoes in the Anopheles genus, and of these, around half are important vectors globally. Only the female of the species bite humans, using your blood to nourish their eggs.

Transmission intensity of malaria is dependent on the type of mosquito in your neighbourhood. If you live in sub-Saharan Africa, you have the misfortune of living alongside Anopheles gambiae, a mosquito that lives a long time and prefers to bite humans over other species.

When the parasite enters your blood, it makes a bee-line for your liver, where it multiplies furiously — a single parasite cell can produce up to 30,000 daughter cells within eight days. The invaders then burst into your bloodstream, invading red blood cells, gorging themselves on the delicious proteins inside, and multiplying themselves further. When the cell contents have been devoured, the little beasts burst out looking for new blood cells to invade, spilling toxins into your bloodstream and evoking an immune response in the process.

All of the symptoms of malaria — fever, headache, fatigue, muscle aches and abdominal discomfort — follow from the parasite’s assault on your red blood cells and your immune system’s response. The spleen swells, trying desperately to clean out infected cells.

Infection with the falciparum variant of malaria is more deadly because it adds sticky proteins to your red blood cells, causing them to latch onto blood vessel walls or other cells, clogging up blood supply to vital organs and leading to severe anaemia (common in young children), respiratory distress, kidney damage, coma and possibly death.

Now you know what causes malaria and what it does to your body. Our next post will discuss some of the social, environmental and political dimensions of malaria; in other words, who gets the disease and why.

References

1. Shah S. The fever : how malaria has ruled humankind for 500,000 years. New York: Sarah Crichton Books; 2010.

2. Malaria Fact Sheet [Internet]: World Health Organisation; 2016. Available from: http://www.who.int/mediacentre/factsheets/fs094/en/.

3. Algar J. Why Some Mosquitoes Spread Malaria and Others Don’t 2014 [Available from: http://www.techtimes.com/articles/21142/20141129/why-some-mosquitoes-spread-malaria-and-others-dont.htm.

4. VectorBase. Anopheles gambiae [Available from: https://www.vectorbase.org/organisms/anopheles-gambiae.

5. White NJ, Pukrittayakamee, S., Hien, T. T., Faiz, M. A., Mokuolu, O. A., & Dondorp, A. M. Malaria. Lancet. 2014;383:723–35.

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