The concept of malaria eradication on a global scale, advocated by the Fourteenth Pan-American Sanitary Conference in 1954, was supported by the Eighth World Health Assembly in Mexico in 1955. In 1957 the World Health Organization approved the principles and practice of malaria eradication activities.
In concept, malaria eradication means the extermination of the malaria parasites of man in the human population of a large area; it does not imply the eradication of the species of Anopheles that transmit the infection. The main conceptual differences between the eradication of malaria and its control is that control attempts only a reduction of the incidence of disease and is virtually a permanent commitment. An eradication program should be limited in time, and aims at the ending of transmission and the elimination of the reservoir of infected cases.
Phases of Malaria Eradication Program And Definition of Malaria Eradication
A malaria eradication program has four phases: preparatory, attack, consolidation, and maintenance. The expected duration of the first three phases that lead to the entry into the maintenance phase is eight years, but this could take longer, as it depends on the epidemiologic features of the area concerned, on technical problems encountered, and on the socioeconomic conditions of the country (vide infra).
The operational methods of malaria eradication are based on an area-wide indoor spraying of dwellings with residual insecticides at the appropriate dosage and frequency. Antimalarial drugs are used either as a complementary method or for prevention of new cases and cure of remaining cases of malaria. Surveillance activities comprise prompt detection, radical treatment, reporting of cases of malaria, and focal spraying. By the end of 1968, of the estimated population of 1733 million people living in the originally malarious areas of the world, a total of 1353 million lived in areas in which eradication programs were in progress or from which malaria had apparently been eradicated. However, there remained 380 million people inhabiting areas of the globe (two thirds of them in tropical Africa) not covered by eradication programs.
In its initial stages, the general progress of the global malaria eradication program was satisfactory, but at the present time a number of biologic, technical, administrative, and other difficulties are hindering its early completion in developing countries and particularly in tropical Africa. Among the technical and biologic problems are the resistance of Anopheles to residual insecticides (DDT or dieldrin) and the high degree of exophily of certain malaria vectors. The type of housing that precludes the use of residual insecticides and mobility of certain human populations must be mentioned. Resistance of plasmodia to present antimalarial drugs is a potentially serious problem. The administrative obstacles are related to the shortages of trained staff, operational shortcomings, financial provision, and other similar problems bearing on the socioeconomic levels of the countries concerned.
The global strategy of malaria eradication was reviewed at the Twenty-Second World Health Assembly (Boston, 1969), and several important changes of policy were made so that control methods could be more widely used in countries where eradication of malaria proves difficult at present.