Malaria Locations in Africa

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QUESTION:

Where in Africa is malaria mainly found?

ANSWER:

The distribution of malaria is constrained by two main factors: temperature and the presence of suitable mosquito hosts. These mosquitoes also depend on certain climatic conditions for their development, namely warm temperatures and sufficient rainfall to produce stagnant water, required by mosquito larvae. As such, although most of Africa lies within latitudes that would normally produce warm enough temperatures for at least seasonal transmission of malaria, in fact the disease is not found everywhere.

spatial distribution Plasmodium falciparum malaria Africa
Spatial distribution of Plasmodium falciparum malaria in Africa. From Hay et al., 2009, “A world malaria map: Plasmodium falciparum endemicity in 2007”, PLoS Medicine 6(3)

Winters in the Mediterranean region and most of the Cape are too cold for malaria, and in these areas, control interventions have largely eliminated the risk of summer sporadic transmission. Similarly, at high elevations, temperatures are too low for the development of the parasite and/or the mosquito vector. For this reason, places such as central Zimbabwe, the high plateau of Ethiopia and even large cities like Nairobi are relatively malaria-free. Finally, the Sahara and Kalahari desert regions are too dry – there is insufficient moisture for the survival of the mosquito vectors.

Based on these factors, the hotspots for malaria transmission in Africa lie in lowland areas with moderate to high rainfall. The map above shows the distribution of Plasmodium falciparum, the most severe and deadly form of the disease.

How quickly should patient take medicine for malaria?

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QUESTION:

My sister has been suffering from malaria for three months. She consulted with doctor in the first symptom of malaria but doctor gave only fever medicine at that time. Blood test was not done at that time. So my question is: “within how many days or months malaria patient has to immediately take medicine?”

ANSWER:

One of our collaborating medical doctors has assisting in providing this answer:

It depends on the type of malaria….with Plasmodium vivax infection she could have a low burden due to concurrent treatment or recent prophylaxis which is breaking through because of low grade resistance. Alternatively, it could be P. malariae or P. ovale, both of which sometimes cause only mild disease that may or may not progress.  P. falciparum shouldn’t act this way; it is usually a much more severe, aggressive infection. Another option is that she might not have malaria at all.  She needs qualitative and quantitative smears to confirm the diagnosis, together with a comprehensive travel/exposure history to support any clinical suspicions.

 

 

Why are platelets low in malaria infections?

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QUESTION:

Why are platelets low in malaria infections? Why is there no internal bleeding in malaria?

ANSWER:

Platelets are low especially with P. falciparum infections, but also potentially with high-burden P. vivax infections. This is probably from sequestration in blood vessels and spleen. Actually, there is life threatening bleeding associated with severe cerebral malaria from this stasis and sequestration in the brain. Similarly, enlargement of the spleen leaves it susceptible to rupture, which would lead to critical internal bleeding.