Malaria control: history shows it's possible by Jose Antonio Najera-Morrondo alaria has always been one of the most serious obstacles to mankind's efforts to develop agriculture, establish permanent settlements or in any way modify the environment. The earliest civilizations recognized that unhealthy conditions could be created by natural disasters, destructive wars or uncontrolled cultivation of the land. It is no exaggeration to say that malaria has been responsible for much of the human suffering and misery accompanying the process of social and economic development. It has also largely "fuelled" the vicious cycle of poverty, ignorance and disease. A well-documented example occurred in southern Europe where, in periods of war or economic depression, the use and the care of land declined; this favoured the transmission of malaria, which contributed to further neglect of land and the lowering of its value, so that the least productive areas became even more intensely malarious. This direct association of agricultural neglect with this disease is enshrined in an old Italian saying that "malaria flees before the plough." the cause of malaria. Medical treatment for fever also has a long history. Besides magic practices, many herbal remedies were prescribed in different areas of the world, some of them with proven antimalarial action. At least four different remedies, including qinghaosu (Artemisia annua), were used in China during the last 2000 years. Nobody knows how long the Peruvian Indians knew of the properties of cinchona before 1500 AD, when an Indian chief offered the bark of the "fever tree" to the Jesuit missionary Juan Lopez. Nearly three centuries later a physician and "inspector of epidemics" recommended to King Charles Ill of Spain that "since cinchona is so effective in treating and preventing this disease, I cannot but In 1630, the Countess of Chinchon cured her recurrent fever with a decoction from the bark of a Peruvian tree.
Early measures Protective devices against mosquitos also date far back in history. Herodotus (484-425 BC) observed that in parts of Egypt, above the marshes, people slept in lofty towers which mosquitos could not reach, while people living in the marshlands slept under nets. In the 13th century AD, Marco Polo noted that the wealthier residents of the Coromandel Coast in India slept on bedsteads with curtains which could be closed at night. Later, mosquito nets and window screens were regarded as protection not only from mosquito bites but also from "miasma! exhalations" (bad air), then thought to be
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beg Your Majesty to take the most appropriate measures to ensure that all the villages of this continent be provided with such an effective antidote, and that it be sold at a moderate price, so preventing the frequent adulterations that apothecaries (chemists) make of this bark" Cinchona is the origin of today's quinine and its derivatives.
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widely from one area to another. The main lesson we have learnt from history is that many spectacular successes were ephemeral and followed by severe resurgences, while areas where malaria control was in tune with local health and social development have maintained their malaria-free status.
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Malaria was a serious obstacle to the .§ colonization of Africa, where the early J5 colonies-particularly in West Africapaid a heavy price to this disease. ..9 Although Europeans were conscious ~ . of the risks and even had some f knowledge of preventive measures, their urge to exploit natural resources as well as strategic considerations often forced them to establish settlements in highly malarious areas. From the late 18th century, better sanitation at the Malaria. Cartoon of Ronald Ross from trading posts and the increasing use of the French paper "Mauritius", 1908. cinchona and later of quinine permitted large-scale European settlement, Guyana (then British Guiana), Taiwan the massive exploitation of African (province of China) and Venezuela. resources-and a century of intensive Tropical Africa and certain parts of slave trading. South-East Asia posed different probBy the mid-19th century, quinine lems because of their very high endewas being routinely taken as prophy- micity, their underdeveloped state and laxis, a method later standardized by their lack of human and financial Robert Koch in 1900, after the resources. Successes elsewhere, discovery of the malaria parasite. although slower than had been Nevertheless the disease provoked anticipated, were nevertheless remarkmajor disasters. Apart from the failure able. But as more and more areas of the French corporation of Ferdi- embarked on the consolidation phase nand de Lesseps during the construc- of the eradication programme, the tion of the Panama Canal, the expectation that a surveillance construction of many roads and rail- mechanism would be sufficient to keep ways approached the grim mortality areas malaria-free once the spraying rate of the Mamore-Madeira Railway in operations stopped was not fulfilled. north-west Brazil, of which it was More and more frequently, there said- perhaps with some exaggeration was a resurgence of the disease, - that it left a dead man for every particularly in Central America and sleeper laid. South-East Asia, culminating in a masSpecific control of the disease began sive epidemic in 1958 in Sri Lanka, with the discovery of the malaria where malaria had been almost eradiparasite in 1880 by Laveran, and of cated. Evidence began to accumulate the mosquito vector by Ross and that, although it was possible to reduce others in 1897. These findings led and even interrupt transmission by rapidly to practical proposals for the insecticide spraying over large areas, it interruption of transmission, and for was very difficult, if not impossible, to appropriate diagnosis and treatment of maintain efficient surveillance in the malaria. absence of a solid health infrastructure. The expectation of global eradication DDT insectidde of malaria was finally abandoned in The idea of malaria eradication, 1969. Present antimalaria strategies are which had been put forward as early as 1916, gained fresh currency after the based on the recognition that, while it Second World War-when epidemics is relatively easy-provided there are had ravaged the devastated areas of sufficient resources-to bring about southern Europe, while the insecticide rapid success in controlling malaria by DOT had appeared to be extremely effective interventions, the sustainabieffective, not only in controlling those lity of malaria control depends on a epidemics but also in dealing with complex of ecological, epidemiological, malaria in such endemic areas as social and cultural factors which vary
Colonial times
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Appropriate control Specialized technical competence is essential to the planning of appropriate control measures, as well as to the training and reorienting of health and medical services so as to improve their performance and ensure the health education of the local population. Great expectations are now being placed on the development of a malaria vaccine. But, again, history shows that some of the major breakthroughs in research were hailed as the final solution to the problem. The discovery of the curative effect of cinchona, the isolation of quinine, the discovery of the malaria parasite and its transmission by anopheline mosquitos, and the recognition of the residual effects of DOT and other synthetic insecticides all led to proposals for the mass control and even eradication of malaria. Looking back at such proposals, the Second Report of the Malaria Commission of the League of Nations in 1927 commented: "The history of special antimalarial campaigns is chiefly a record of exaggerated expectations followed sooner or later by disappointment and the abandonment of work" Unfortunately that comment is still valid, after the renewed optimism that had been engendered by DOT. A healthy scepticism towards panaceas for malaria control does not mean it would be justified to abandon the more than one hundred million people now suffering from the disease, or to forget that nearly half of the world's population is at risk Although malaria eradication is not feasible at present, malaria mortality and a great deal of the suffering caused by the disease can be eliminated by the judicious use of available technology. Eventually, as part and parcel of health, social and economic development, the malaria risk itself can also be • eliminated. Dr Jose Antonio NajeraMorrondo is Director of the Division of Control of Tropi cal Diseases. WHO. 121 1 Geneva 27 . Sw itzerland.
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