July 4, 2012
Article by Global Pre-Meds
Hospital doctor shadowing & global health experience programs.
Malaria is a problem in several areas of the world, mainly in a band around the Equator, but approximately 90% of the deaths occur in Sub-Saharan Africa and sadly, 60% of those deaths occur in children under five. Prevention is not easy in areas where there is little recourse to drugs, insecticides and mosquito nets, all of which are effective when used properly, so many populations in Africa, especially in Cote d’Ivoire, Burkina Faso and Angola (the three countries which have the unenviable position as the countries with the highest death rates per 100,000 population in the world) are at serious risk.
Sickle cell anaemia, a very common congenital haemoglobin anomaly in Africa, is a natural defence against malaria, but unfortunately carries with it is own secondary problems of anaemia, joint problems and possible liver damage in later life. The anomalous haemoglobin molecule makes the cells take on a sickle shape and become inflexible; this is what causes the joint problems and liver damage as the bad news, but the good news is that cells such as these are not able to be parasitized by the malaria plasmodium, so giving a degree of immunity against this killer. Were it not for the relatively common occurrence of the HbS variant, the deaths from malaria in Sub Saharan Africa would be occurring in even greater numbers.
The malaria parasite is only spread by mosquitoes, who pass on the plasmodium in exactly the most dangerous stage to the human (and many animals as well) when they bite them. The mosquito injects a small amount of anticoagulant saliva when they bite, to make feeding easier and it is then that the parasite is passed over. On the other side of the coin, if the mosquito bites an infected person, the parasite passes to the mosquito when they feed. This is so simple and is achieved in seconds, which is why the malarial parasite is so successful, from its own standpoint. A ‘good’ parasite does not kill its host unnecessarily and malaria is no exception. Enough people live for long enough to ensure the cycle goes on and even when prophylaxis is used, there are enough people infected to make sure that the mosquito population in any area have enough infected victims to prevent the complete eradication of malaria. Historically, quinine was used as a prophylactic – leading to the anecdotal evidence that all ex-pats in Colonial Africa lived on gin and tonic – but it is not really a proper preventative and all malarial strains are now building up a resistance to most of the other drugs on the market.
The only real preventative against malaria if you live in a malarial area is spraying with insecticide and the use of mosquito nets. Only mosquito nets are without side effects and some malarial parasites are becoming immune to insecticides. There is no vaccination available against malaria, although work continues, and the prophylaxis has some serious side effects in many users and is not really safe for permanent use. This means that malaria will remain a serious problem in Africa for the foreseeable future and the only real defence against it is keeping waterways clean and free of the mosquito larvae and the careful use of mosquito nets wherever possible.