Criticism of WHO's revised malaria eradication strategy

Fred L. Soper played a key role in promoting the idea that malaria could be eradicated world-wide. He believed eradication to be feasible based on the ability of household insecticide spraying to interrupt malaria transmission. He opposed WHO's strategy to reduce the number of years devoted to spraying and to rely instead on chemotherapy to wipe out remaining foci of malaria. While his criticism was intense, it neither featured in the discussions of the World Health Assembly nor the WHO malaria Expert Committee. The author concludes that had his criticism been heard the global campaign could have been stopped far earlier than in fact it was. Furthermore, failure to openly address Soper's criticism represented a major failure on the part of the WHO Secretariat to ensure that policy decisions reflected a full consideration of all underlying issues, technical or otherwise.     

Some lessons for the future from the Global Malaria Eradication Programme (1955-1969)

Encouraged by the early success of using dichloro-diphenyl-trichloroethane (DDT) against malaria, the World Health Organization (WHO) embarked on the Global Malaria Eradication Program (GMEP) in 1955. Fourteen years later, the campaign was discontinued when it was recognised that eradication was not achievable with the available means in many areas, although the long-term goal remained unchanged. During the GMEP, malaria was permanently eliminated from many regions. In other areas, however, substantial gains were lost in resurgences, sometimes of epidemic proportions. During the 1970s and 1980s, because of economic and financial crises, international support for malaria control declined rapidly, but in the past decade, following increasing demands from endemic countries and promising results from scaling up of control activities, interest in malaria elimination and the long-term goal of eradication has received international political and financial support. In 2007, there was a renewed call for malaria eradication and a consultative process to define a research and development agenda for malaria eradication (malERA) was established. Lessons learned from the GMEP (1955-1969) highlight the fact that no single strategy can be applicable everywhere and that a long-term commitment with a flexible strategy that includes community involvement, integration with health systems, and the development of agile surveillance systems is needed.     

Epidemiology in the strategies for malaria control

A rapid overview is presented of the evolution of the main orientations of malaria control, since the discovery of mosquito transmission. Stated control objectives appear to have oscillated between expectations to eradicate the vector, or at least the disease, and more modest approaches to minimise the effects of the infection. High optimism was raised when a new control measure, or new combination of existing measures, appeared to be highly effective and was expected to have universal applicability. The implementation of large scale campaigns eventually found the limits of applicability of the proposed strategy and the exaggerated expectations soon gave way to disillusion and, eventually, to a revival of research. The longest and most impacting period of exaggerated expectations was the global malaria eradication campaign of the 1950s and 1960s, which completely disregarded the study of local epidemiology, considering that all it was needed was to know if an area was "malarious" or not. Research was practically abandoned and, even when reinstated after the recognised failure of the campaign, it has retained an almost exclusive orientation towards the development of control tools, drugs or eventually vaccines. One of the earliest victims of the eradication campaign was the study of epidemic malaria and its determinants in different epidemic prone areas. In spite of an extremely long period of disillusion, lasting for almost two decades, the reality of the malaria problem led WHO and member countries to agree on a global strategy of control, aiming at a realistic use of existing tools, to at least reduce or prevent mortality. An essential element of this strategy is the prevention or control of malaria epidemics and the selective use of vector control, both of which have to be based on a solid knowledge of local epidemiology, the study of which has to rejoin the path abandoned fifty years ago.     

Epidemiology and control of malaria in Colombia

Malaria is currently one of the most serious public health problems in Colombia with an endemic/epidemic transmission pattern that has maintained endemic levels and an average of 105,000 annual clinical cases being reported over the last five years. Plasmodium vivax accounts for approximately 70% of reported cases with the remainder attributed almost exclusively to Plasmodium falciparum. A limited number of severe and complicated cases have resulted in mortality, which is a downward trend that has been maintained over the last few years. More than 90% of the malaria cases in Colombia are confined to 70 municipalities (about 7% of the total municipalities of Colombia), with high predominance (85%) in rural areas. The purpose of this paper is to review the progress of malaria-eradication activities and control measures over the past century within the eco-epidemiologic context of malaria transmission together with official consolidated morbidity and mortality reports. This review may contribute to the formulation of new antimalarial strategies and policies intended to achieve malaria elimination/eradication in Colombia and in the region.     

Malaria Transmission and Fetal Growth

In view of the known relation between infection of the maternal circulation of the placenta with Plasmodium falciparum and impaired fetal growth a study was made of the effect on birth weights of a malaria eradication campaign in the British Solomon Islands. Mean birth weights rose substantially within months of starting antimalarial operations. The increases between 1969 and 1971 averaged 252 g in babies of primigravidae and 165 g in all babies. The proportion of babies with birth weights of less than 2,500 g fell by 8% overall and by 20% among babies of primigravidae. The adverse effect of malaria transmission on fetal growth was apparently reversible if transmission of infection in the community was interrupted up to as late as the third trimester of pregnancy. The beneficial effects of malaria eradication operations on infant survival, child development, and social attitudes in developing countries are discussed.     

Forty years of malaria eradication in Sardinia. A new appraisal of a great enterprise

The campaign against malaria in Sardinia carried out by the Ente Regionale per la Lotta Anti-Anofelica in Sardegna (ERLAAS), appears today as one of the greatest efforts against malaria since the discovery of its aetiology and mode of transmission. The disease was eradicated without achieving the eradication of the vector, Anopheles labranchiae, the main objective of the campaign. This species eradication failure had been at first attributed to the indigenous character of A. labranchiae and its long standing in the island. A more recent analysis, based on paleoclimatological information, makes virtually impossible the presence of A. labranchiae during the last (Würm) glacial period and indicates a comparatively recent introduction of the species in the island. It was the absence of A. atroparvus, with which it has usually to compete in Southern Europe, what permitted the wide distribution of A. labrianchiae in the island. Four decades after the events the concept of species eradication as an anti-malaria weapon appears as basically wrong, the results of Sardinia as well as those obtained in the Italian mainland having demonstrated that the eradication of the vector was not required for the successful eradication of the disease.     

India eradicates guinea worm disease

The WHO officially certifies India and other countries of the South East Asian regions as free of guinea worm disease. The eradication was made possible through the efforts of the Indian government to launch a national guinea worm eradication program in 1983-84, and a sustained campaign at the grass-roots level by agencies such as the UN International Children's Fund and the WHO in collaboration with the government. The recognition was based on the report gathered by three members of the 4th International Commission for Certification of Dracunculiasis Eradication, who visited India in November 1999 and conducted an investigation in 62 villages in 5 states where the disease had been endemic. Also, the national eradication program had been evaluated 7 times and showed remarkable achievement.     

A sticky situation: the unexpected stability of malaria elimination

Malaria eradication involves eliminating malaria from every country where transmission occurs. Current theory suggests that the post-elimination challenges of remaining malaria-free by stopping transmission from imported malaria will have onerous operational and financial requirements. Although resurgent malaria has occurred in a majority of countries that tried but failed to eliminate malaria, a review of resurgence in countries that successfully eliminated finds only four such failures out of 50 successful programmes. Data documenting malaria importation and onwards transmission in these countries suggests malaria transmission potential has declined by more than 50-fold (i.e. more than 98%) since before elimination. These outcomes suggest that elimination is a surprisingly stable state. Elimination''s ‘stickiness’ must be explained either by eliminating countries starting off qualitatively different from non-eliminating countries or becoming different once elimination was achieved. Countries that successfully eliminated were wealthier and had lower baseline endemicity than those that were unsuccessful, but our analysis shows that those same variables were at best incomplete predictors of the patterns of resurgence. Stability is reinforced by the loss of immunity to disease and by the health system''s increasing capacity to control malaria transmission after elimination through routine treatment of cases with antimalarial drugs supplemented by malaria outbreak control. Human travel patterns reinforce these patterns; as malaria recedes, fewer people carry malaria from remote endemic areas to remote areas where transmission potential remains high. Establishment of an international resource with backup capacity to control large outbreaks can make elimination stickier, increase the incentives for countries to eliminate, and ensure steady progress towards global eradication. Although available evidence supports malaria elimination''s stickiness at moderate-to-low transmission in areas with well-developed health systems, it is not yet clear if such patterns will hold in all areas. The sticky endpoint changes the projected costs of maintaining elimination and makes it substantially more attractive for countries acting alone, and it makes spatially progressive elimination a sensible strategy for a malaria eradication endgame.     

Campaigns for the eradication of malaria in Tunisia: history and current situation

The authors recall the historic of the different campaigns conducted against the malaria in Tunisia. Started since 1903 under the direction of Charles Nicolle, these campaigns were taken over after the end of each world war. However it must be necessary to wait the last campaign from 1966 to 1972, to conclude at the eradication of the disease, in 1977, into the country. Since this date, the systematic control of malaria is always conducted in the country. This end control is objected to avoid the resurgence of this parasitic disease in Tunisia, for the number of imported cases is increasing and the country presents ecological conditions propitious to Anopheles.     

Design and implementation of a mosquito database through an entomological ontology

There have been constant changes in the biology and behavior of the vector and parasite involved in the transmission of malaria. There is limited interest in developing new technologies and procedures for controlling the underlying factors of this threat, which poses an enormous challenge to health systems. To understand the various vector species and their interrelations is of prime importance in understanding the transmission mechanisms of malaria in order to react efficiently. To attain this objective, we have used an ontological approach to producing a database that we consider to be our own contribution in helping to control malaria vectors if eradication has been unsuccessful in the previous control campaign.     

A research agenda for malaria eradication: drugs

Antimalarial drugs will be essential tools at all stages of malaria elimination along the path towards eradication, including the early control or "attack" phase to drive down transmission and the later stages of maintaining interruption of transmission, preventing reintroduction of malaria, and eliminating the last residual foci of infection. Drugs will continue to be used to treat acute malaria illness and prevent complications in vulnerable groups, but better drugs are needed for elimination-specific indications such as mass treatment, curing asymptomatic infections, curing relapsing liver stages, and preventing transmission. The ideal malaria eradication drug is a coformulated drug combination suitable for mass administration that can be administered in a single encounter at infrequent intervals and that results in radical cure of all life cycle stages of all five malaria species infecting humans. Short of this optimal goal, highly desirable drugs might have limitations such as targeting only one or two parasite species, the priorities being Plasmodium falciparum and Plasmodium vivax. The malaria research agenda for eradication should include research aimed at developing such drugs and research to develop situation-specific strategies for using both current and future drugs to interrupt malaria transmission.     

Overview of malaria control in the Americas

The malaria endemic countries of the Americas have adopted in 1992 the WHO Global Malaria Control Strategy whose difficulties of implementation have been compounded to a major reform in the health sector, as the countries adjust to conform to financial scarcity and new economic policies. Most countries of the Region have reoriented its control program from eradication of malaria to the elimination of malaria mortality and morbidity. The Region has advanced towards these objectives having already reduced its mortality by 60% and is now in the final stages of applying new tools to control transmission and rapidly advance to reduce the incidence of malaria in the Americas.     

Should the use of DDT be revived for malaria vector control?

Indoor residual spraying with DDT was the principle method by which malaria transmission was eradicated or greatly reduced in many countries between the late 1940s and 1970s. Since then, decreasing use of DDT has been associated with a resurgence of malaria in India, Sri Lanka, former Soviet Central Asia, Zanzibar, Venezuela and several other Latin American countries. In India and Zanzibar, DDT resistance in vectors, as well as a decline in spray coverage, are probable causes of reduced effectiveness of DDT in recent decades. In southern Europe, eradication of malaria transmission was achieved by DDT spraying in the 1940s and 50s and eradication has been sustained by adequate treatment of imported human malaria cases. In the highlands of Madagascar and South Africa, recent reversion to DDT spraying has been successful in stemming resurgences of malaria. Continued use of DDT for vector control, but not for agriculture, is approved by the Stockholm Convention on Persistent Organic Pollutants. DDE residues in breast milk have been associated with DDT anti-malaria spraying in South Africa, but it is not known whether this is harmful. A claimed association of DDE residues with breast cancer have not been substantiated. There is a recent report of association of DDE residues with probability of premature birth; the possible relevance of this to anti-malarial use of DDT should be investigated. In Colombia, testing of the DDT stockpile for suspensibility, DDT resistance in Anopheles darlingi and investigation of the present affordability of widespread spraying with DDT, compared with alternative chemicals, are recommended.     

Therapeutic efficacy of 3 treatment protocols for non-complicated Plasmodium falciparum malaria, Antioquia, Colombia, 2002

High resistance of Plasmodium falciparum malaria to chloroquine poses malaria as a major public health problem in Colombia. In this context, the therapeutic response of uncomplicated P. falciparum malaria patients to chloroquine (CQ), sulfadoxine/pirymethamine (SDXP) and combined therapy (SDXP/CQ) was evaluated according to the WHO/PAHO protocols of 1998. The comparisons were based on a sample of 160 patients with uncomplicated P. falciparum malaria in Turbo and Zaragoza (Antioquia, Colombia). Patients were randomly assigned each of the treatment categories. The results were statistically similar in each municipality. In Turbo percentage of treatment failure was 87.5%, 22.2% and 22.6% for CQ, SDXP and SDXP/CQ, respectively, whereas in Zaragoza, the corresponding treatment failure was 77.7%, 26.5% and 12.1%. During follow up, 50% of subjects with late treatment failure were asymptomatic in Turbo, while 33.3% were asymptomatic in Zaragoza. A high level of treatment failure occurred with CQ monotherapy, while SDXP and SDXP/CQ had acceptable levels of failure, i.e., below 25%. The high percentage of late treatment failure in asymptomatic patients may contribute to increased risk of persistent transmission.     

Malaria control: achievements, problems and strategies

Even if history has not always been the Magistra vitae, Cicero expected it to be, it should provide, as Baas said, a mirror in which to observe and compare the past and present in order to draw therefrom well-grounded conclusions for the future. Based on this belief, this paper aims to provide an overview of the foundations and development of malaria control policies during the XX century. It presents an analysis of the conflicting tendencies which shaped the development of these policies and which appear to have oscillated between calls for frontal attack in an all-out campaign and calls for sustainable gains, even if slow. It discusses the various approaches to the control of malaria, their achievements and their limitations, not only to serve as a background to understand better the foundations of current policies, but also to prevent that simplistic generalisations may again lead to exaggerated expectations and disillusion. The first part of the paper is devoted to the development of malaria control during the first half of the century, characterised by the ups and downs in the reliance on mosquito control as the control measure applicable everywhere. The proliferation of "man-made-malaria", which accompanied the push for economic development in most of the endemic countries, spurred the need for control interventions and, while great successes were obtained in many specific projects, the general campaigns proposed by the enthusiasts of vector control faced increasing difficulties in their practical implementation in the field. Important events, which may be considered representative of this period are, on the campaign approach, the success of Gorgas in the Panama Canal, but also the failure of the Mian Mir project in India; while on the developmental approach, the Italian and Dutch schools of malariology, the Tennessee Valley and the development of malaria sanitation, included the so called species sanitation. The projection of these developments to a global scale was steered by the Malaria Commission of the League of Nations and greatly supported by the Rockefeller Foundation. Perhaps the most important contribution of this period was the development of malaria epidemiology, including the study of the genesis of epidemics and their possible forecasting and prevention. Although the great effectiveness of DDT was perhaps the main determinant for proposing the global eradication of the disease in the 1950s, it was the confidence in the epidemiological knowledge and the prestige of malariology, which gave credibility to the proposal at the political level. The second part deals with the global malaria eradication campaign of the 1950s and 1960s. It recognises the enormous impact of the eradication effort in the consolidation of the control successes of the first half of the century, as well as its influence in the development of planning of health programmes. Nevertheless, it also stresses the negative influence that the failure to achieve its utopian expectations had on the general disappointment and slow progress of malaria control, which characterised the last third of the century. The paper then analyses the evolution of malaria control funding, which often appears out of tune with political statements. The fourth part is devoted to the search for realistic approaches to malaria control, leading to the adoption of the global malaria control strategy in Amsterdam in 1992, and the challenge, at the end of the century, to rally forces commensurate with the magnitude of the problem, while aiming at realistic objectives. After discussing the conflicting views on the relations between malaria and socio-economic development and the desirable integration of malaria control into sustainable development, the paper ends with some considerations on the perspectives of malaria control, as seen by the author in early 1998, just before the launching of the current Roll Back Malaria initiative by WHO.     

Eradication of Yaws: Historical Efforts and Achieving WHO's 2020 Target

Background

Yaws, one of the 17 neglected tropical diseases (NTDs), is targeted for eradication by 2020 in resolution WHA66.12 of the World Health Assembly (2013) and the WHO roadmap on NTDs (2012). The disease frequently affects children who live in poor socioeconomic conditions. Between 1952 and 1964, WHO and the United Nations Children''s Fund (UNICEF) led a global eradication campaign using injectable benzathine penicillin. Recent developments using a single dose of oral azithromycin have renewed optimism that eradication can be achieved through a comprehensive large-scale treatment strategy. We review historical efforts to eradicate yaws and argue that this goal is now technically feasible using new tools and with the favorable environment for control of NTDs. We also summarize the work of WHO''s Department of Control of Neglected Tropical Diseases in leading the renewed eradication initiative and call on the international community to support efforts to achieve the 2020 eradication goal. The critical factor remains access to azithromycin. Excluding medicines, the financial cost of yaws eradication could be as little as US$ 100 million.

Conclusions

The development of new tools has renewed interest in eradication of yaws; with modest support, the WHO eradication target of 2020 can be achieved.     

Parasitoses and development: malaria and echinococcosis]

After having placed emphasis on the cyclic oscillations characterizing the interest of the scientific and political world for parasitology, the author analyzes the various standpoints from which parasitic diseases, and above all malaria, have been dealt with ever since the beginning of this century. Specific criticism is addressed to the military model, which has provided the basis for many eradication campaigns. The author also analyzes the "vicious circle theory", which labelled the activity of the WHO in its first decade of life, and which assumed that breaking the disease and underdevelopment circle was possible by acting mainly or even exclusively on endemic and debilitating diseases. Both these models were tested with success in Sardinia with the 1947-49 antimalaria campaign. However, socio-economic development of the island did not occur as expected, and attempts to export the same approaches to other parts of the world soon disclosed their limitations, leading to major failures. The experience on the fight against echinococcosis is subsequently examined. The conclusions drawn are that many successes may be obtained through a systemic rather than a sectorial approach; and that a "conflicting cohabitation" with diseases is foreseen as a long-lasting reality, and must thus be controlled with the appropriate means.     

Strategies for malaria control in Colombia

Attempts at malaria eradication this century have been highly effective but early successes have not been sustained. This has been ascribed to the lack of community involvement in these campaigns. Colombia has put huge effort into malaria control on a number of fronts, from vaccine development to the evaluation of the integrated use of more traditional methods. William Rojas, Fernando Pe?aranda and Mouricio Echavarria describe a pilot programme for integrated malaria control in Colombia whose success they attribute to committed community participation.     

Design and implementation of a mosquito database through an entomological ontology

There have been constant changes in the biology and behavior of the vector and parasite involved in the transmission of malaria. There is limited interest in developing new technologies and procedures for controlling the underlying factors of this threat, which poses an enormous challenge to health systems. To understand the various vector species and their interrelations is of prime importance in understanding the transmission mechanisms of malaria in order to react efficiently. To attain this objective, we have used an ontological approach to produce a database that we consider to be our own contribution in helping to control malarial vectors if eradication has been unsuccessful in the previous control campaign.