Malaria is a major health problem and is thought to be responsible for about 18% of all deaths of children aged under five years in sub-Saharan Africa, or between 700 000 and 900 000 children each year, as well as aiding the spread of other diseases such as HIV/AIDS by weakening the immune system. Trials to develop an effective vaccine are ongoing. However, treatments using the anti-malarial properties of the bark of the chinconcha tree have been known for centuries, and used for many years against the disease until its active ingredient, quinine, began to be produced artificially.
The folio records a letter from the Royal Society’s prolific correspondent and later member Henri Justel, which mentions ‘Jesuits Bark’, the name being given to the bark of the Peruvian chinconcha tree. The letter does not survive, but the bark was not forgotten and together with numerous other substances it was boiled together with water, spirit of wine and white wine (RB. 6. 213, 1685) in Mr Pappin’s ‘digesting’ machine. Impressed, Pappin reported back that the bark lasted three or four time longer than bones before being reduced to a powder. There is no mention of the medical properties of the bark here, however, and the next reference to it in the Royal Society records occurs in the Philosophical Transactions of 1737/8. By this time the bark is clearly in demand: the author Dr Grey gives detailed information about the four different types of tree in Peru, their various effects and preparations, and reports that the drug enters Europe through Panama. He goes on to express concern that the exploitation by the Spanish will soon wipe out the local indigenous population who had been well aware of the anti-malarial properties of the plant well before the arrival of the colonisers, and that the bark will become scarce due to over-exploitation.
Anti-malarial drugs and the development of insecticides that kill the mosquitos carried the disease were of course a valuable tool in the exploration and final colonisation of Africa by European powers during the next century. This provided impetus for the identification of the parasite of the genus Plasmodium and the artificial production of quinine. Concerns like those expressed by Grey about the availability and intellectual property surrounding anti-malarial drugs still exist today. Problems with malaria prevention include the tendency for insects to develop resistance to insecticides like DDT, as well as their potentially negative environmental and health effects. The Royal Society has continued to engage with the problem of malaria: Hiliary Ranson is currently conducting research into the DNA of insecticide-resistant plasmodium in an attempt to evolve a method of blocking the process of development of resistance. Her research is demonstrated by this interactive tool. The recent winner of the Royal Society’s Pfizer Award, Dr Alex Nzila has taken a different approach: focusing on drug resistance in humans, he has shown that resistance can be reduced by combining an existing anticancer drug, methotrexate, with folic acid.
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