Learning from Failure
Renewed interest in malaria at home and abroad makes this a politically opportune time for new initiatives. Articles in both the popular press and scientific journals have called attention to the looming crisis posed by the disease. In January 1997, malaria experts from 35 countries and representatives from the major agencies that fund malaria research convened at an international conference to address the spread of the disease in Africa. And the World Health Assembly, the governing body of the World Health Organization (WHO), passed a resolution calling on member states to renew their political commitment to malaria control and to guarantee sufficient funding, staff, and other resources to sustain this effort.
This is not the first time that public and private agencies have geared up to assault the disease. In the 1950s, WHO, the United Nations International Children’s Emergency Fund (UNICEF), and the U.N. Food and Agriculture Organization enthusiastically declared that the time was right to eliminate malaria as a public health problem throughout the world. The malaria eradication programs they sponsored relied on a combination of prevention – spraying with the insecticide DDT – and early identification and treatment of infected individuals, deploying an arsenal of new antimalarial drugs, the best known of which was chloroquine. (Although WHO described this effort as a global eradication campaign, sub-Saharan Africa was not included in the early phases, probably because high transmission rates, the lack of administrative and financial resources, and the logistical problems of reaching rural areas were so daunting. Presumably, the plan was to include Africa after success had been demonstrated elsewhere.)
Despite its initial promise, the DDT campaign backfired. Programs in many malaria-endemic countries were unable to sustain the level of thoroughness and efficiency required to make residual insecticide spraying effective. The result was inadequate or erratic coverage. Mosquitoes that survived low doses of insecticide reproduced, creating populations of insecticide-resistant, malaria-carrying pests. In response to erratic spraying, mosquitoes simply changed their behavior – for instance, they stopped settling on the walls of houses that had been sprayed and moved to nearby vegetation that hadn’t.
Where the malaria eradication program worked, it soon became a victim of its own success. As the incidence of malaria became negligible in these areas, international organizations downgraded the disease as a priority health issue; at the national level, politicians and government agencies withdrew their support. The result was a dramatic resurgence of infection. In Sri Lanka, for instance, the incidence of malaria reached its lowest point in 1963, when 17 cases were reported. But by 1969, the number of registered cases had shot back up to more than half a million. Today Sri Lanka, like most other malarious countries, is still struggling to control the disease and has abandoned the goal of eradication. Overall, the eradication campaign showed little result outside the United States, Europe, and some parts of northern Africa.
Compounding the political failure of these early efforts was the emergence of drug resistance. As early as 1960, chloroquine-resistant strains of Plasmodium falciparum, the parasite that causes the most deadly form of malaria in humans, began to spread in Southeast Asia and South America. In Southeast Asia, resistance to second-generation drugs such as Fansidar emerged rapidly after their introduction for treatment of chloroquine-resistant infections. Resistance to both chloroquine and Fansidar has now spread to Africa and infections with multidrug-resistant P. falciparum are now common in many areas where the parasite is endemic.
To the extent that the parasite represents a moving target for drugs and insecticides, no single chemical compound is likely to defeat it. In the 1950s, we had the best weapons against malaria that we’ve ever had, yet we failed to control the disease. The failure of these early eradication campaigns teaches that multiple strategies – and a sustained commitment of significant resources – are required to solve the problem.
Over the past two decades, however, we have failed to apply that lesson. Indeed, past interventions have done more to eradicate funding for malaria research than they have to eliminate disease. In the initial years of the eradication effort, DDT appeared so promising that international agencies saw little need to study the disease further. Only in 1965, 15 years after the eradication program began, did WHO finally begin to encourage malaria research. The de-emphasis on science combined with a decline in the number of malariologists left countries ill prepared to deal with the crisis we face today.
Research on malaria remains severely underfunded. According to a 1996 report released by the Unit for Policy Research in Science and Medicine (PRISM) of the Wellcome Trust, a private charity that is one of the major sponsors of biomedical research, expenditures for malaria research equal about $42 per death, while expenditures for research on diseases like AIDS, cancer, or asthma are 100 to 1,000 times higher. According to the PRISM report, in 1993 only $84 million was spent on malaria research worldwide. The largest share – more than one-quarter – was devoted solely to vaccine development. Indeed, for decades, the hope of defeating malaria has rested largely on the belief that a vaccine for the disease is just around the corner.