.
In: 0
We eliminated it with an ungodly amount of DDT, which we only realized later was wreaking havoc with the environment (as detailed in the book Silent Spring). Other parts of the world either lack the infrastructure for such systematic spraying or are concerned about the environmental effects (there may also be some legal stuff wrapped up in this part, as DDT is banned in some places).
The malaria parasite and the mosquito host are actually found across most of the world. However a specific set of criteria must be met in order for the disease to become a public health crisis.
The temperature has to be consistently high enough (around 27 degrees C) for optimum parasite and mosqutio development. Older mosquitos spread the disease more, because the parasite takes around 7-10 days inside the host to get to the transmission stage.
In countries with good sanitation, good health service provision and lengthy periods of cooler temperatures, not enough mosquitos survive long enough to pick up and incubate the parasite. Those very few people who do get infected tend to get treated pretty promptly.
Sub Saharan Africa has around 90% of global malaria cases because a) they have a high pool of people infected already b) infected people find it harder to access treatment, so they have more chance of a mosquito picking up the parasite from them and c) the long warm rainy seasons and poorer quality housing provide more opportunities for older mosquitos to come into contact with humans.
The African mosquito Anopheles gambiae is also a particularly efficient vector as it shows a preference for biting humans. Other mosquitos will also target birds and livestock.
Latest Answers