Current estimates of the number of people who die annually from malaria in the world today range from 1.1 to 2.7 million. The annual incidence of clinical cases of malaria is estimated to be between 300 and 500 million. In light of numbers of this magnitude, the World Health Organization (WHO) and a diversity of governmental and private organizations are attempting to put into place a new set of initiatives with the stated objective of dramatically reducing the malaria burden in the 100 countries and territories where transmission is currently active.

There is now a major emphasis on research, with the transition from stated objective to actual strategy emphasizing development of new tools such as vaccines, transgenic mosquitoes, and a new generation of antimalarial drugs. Extant tools (e.g., insecticide-impregnated mosquito nets, combination of antimalarial drugs, and chemical insecticides such as DDT) are often discussed in cost-effectiveness analyses where only a single tool at a time is assessed. Overall, however, the entire discussion of strategy is centered around research leading to new high technology interventions. The disconcerting feature of this emphasis is that the research community itself - the immediate beneficiary of the resources being brought to the table - is forecasting time horizons of 12-15 years before new tools would actually be ready for large-scale antimalarial campaigns.

By accepting these estimates at face value and accepting the fact that mosquito nets alone or the use of combinations of extant antimalarials are not going to solve the vast malaria problem, the question immediately arises as to whether or not there are any potentially effective malaria control strategies that can be put into place now. An immediate, almost embarrassing, affirmative answer to this question derives from the fact that the basic technologies and strategies for implementation are well described in the historical literature focused on successful malaria control programs.

Virtually without exception, the successful programs note that:

(1) Environmental management is the central focus, with several intervention or surveillance methods acting simultaneously (e.g., different combinations of larvicides, vegetation clearance, drainage of standing water, house screening, surveillance of mosquito larvae, use of larvivorous fish, intermittent irrigation).

(2) Tuning the package of interventions to minimize the number of malaria cases per year is an adaptive process involving ongoing performance evaluations of each of the tools and of the outcome measure. (Interventions are adjusted over time in response to these evaluations.)

(3) Three to five years was required before a given package of interventions exhibited a high level of performance.

(4) Diagnosis of malaria cases, antimalarial drugs, mosquito nets, and the use of chemical insecticides (following the discovery of DDT) were necessary but, decidedly, not sufficient components for success of the program.

(5) The program staff contained people knowledgeable about entomology, hydrology, epidemiology, ecology, and clinical aspects of malaria.

(6) The implementation strategy, including the mix of tools employed, was highly idiosyncratic to the particular locality.

Point 6 is of fundamental importance for thinking about what to do now.

A diversity of malaria control programs, emphasizing the adaptive tuning of interventions to achieve sustained high-level performance, is exemplified by a consideration of British colonial experiences and rice field malaria control under the commune system in China. The ecological settings included the copper belt in northern Rhodesia, rubber and tea plantations in the Malay states, jungle villages on the island of Borneo, and irrigated rice fields in China.

The take-home lessons of the successful control programs in these settings are the locality-specific implementation strategies. The question raised by these examples is: what should replace the colonial infrastructure, including the financial resources, in the multifaceted political and cultural environments of the tropics today? In addition, we need to identify strategies outside of the Chinese commune system for forging cooperative agriculture-health linkages in irrigated rice field zones so that malaria control and, correlatively, increased rice yield, can be sustained on a wide scale in the tropics today.

Organization and implementation of control programs - modeled, in terms of technical detail, on the colonial and commune experiences, but consistent with contemporary regional, national, and, above all, local political realities - are the fundamental challenges for achieving sustained malaria control now and in the future. Major emphasis should be given to strong financial, educational, and technical support of local primary health care facilities. This broad but inadequately supported infrastructure can be the base of operations for malaria control now. In addition to supporting major general improvements in local health services, I envision a small augmentation of personnel at primary health care facilities to include an entomologist and hydrologist. Depending upon the locality, the establishment of symbiotic relationships with the local agricultural personnel would also be essential. The Chinese rice field experience is a role model for this; however, we need to seek the analogue of this cooperative experience throughout the tropics, where a commune-like system does not exist.

Connecting malaria control to the health services is not a new postcolonial idea. The WHO Expert Committee on Malaria meeting in 1986 indicated that where a strong health infrastructure exists, guided by "strong leadership oriented towards primary health care and preventive services, most routine anti-malaria activities, including vector control, could be undertaken as part of primary health care." Where the infrastructure is less developed, "a specialized unit may be required for some vector control operations." However, where malaria "is a high priority problem" and where primary health care is weakly developed, "a special project may be the only effective means of implementing antimalaria action." The requisite financial resources and an international political will to implement these recommendations has been lacking to date. Here is a place where investment now can make a major difference for malaria control today.

Linkage of the above proposals to international financial resources and national governments requires that a major case be made about why engagement in the types of programs delineated above is, in fact, in the interest of any national government seeking to escalate economic development and establish a solid base in the international economic community. Here again, there are useful lessons from the colonial period. The overarching lesson from the past was that malaria simply prevented economic development. Malaria control in the British colonial experience can hardly be viewed as an altruistic act, targeted at improving the health of local populations in the tropics. It was viewed by the colonial authorities as essential for successful economic development, exploitative of the local population as it was. The common denominator of this experience with the present situation in the tropics is that successful malaria control is still essential for economic development. The issue at hand is how, organizationally, to carry this out so that there is truly elevation of living standards of the local people and economic growth at the district and national levels.

One limitation of the specific examples mentioned above (i.e., the copper belt in northern Rhodesia) is that they focus attention on what can be done in stable communities. This leaves out the substantial contribution of migration-related malaria transmission to the present malaria problem in the tropics. Some insight about how to proceed in these settings (e.g., on the Amazon frontier in Brazil, along the border areas between Thailand and Burma) can be acquired from investigation of the interrelationships between unstable human population movements, ecological transformation, changing land use, and malaria transmission. The word "control" seems to be quite inappropriate in this context. A more useful concept is that of malaria mitigation.

Lessons learned from studies of malaria related to colonization projects on the Amazon frontier indicate that rapid forest clearance (for an agricultural settlement), simple behavioral measures (e.g., staying indoors near dawn and dusk when anopheles biting is at its peak), and locating houses on hills and away from the forest fringe are among a myriad of straightforward mitigation steps that can be implemented now. From the perspective of even malaria mitigation, the negative Amazon experience, to date, at least clarifies what went wrong when new frontier lands were opened for human settlement in the past. They also clearly reveal the likely structure of what could be successful mitigation programs in the future. An essential feature of a contemporary response to the malaria challenge is to develop the organizational mechanisms for bringing malaria mitigation into the international malaria portfolio. The economic incentives for doing this are strong. Indeed, malaria mitigation in zones of unstable human population dynamics can be readily rationalized on grounds of its economic benefits. It provides further support for our answer to the general question: is there an economic basis for malaria control in the tropics? My position is emphatically, yes.

Finally, we need to consider how to integrate control strategies that can be implemented today with the new tools that, if the currently emphasized high technology research is successful, would be coming on stream 10 to 15 or more years in the future. At the present, there is also a need to emphasize education of trained personnel throughout the tropics by taking advantage of the vast information capabilities of the Internet in order to link the limited number of highly skilled personnel to those local areas where enhanced technical and organizational expertise is needed. In this regard, there is already a diversity of excellent Web sites that could readily be adapted to serve as resources for training, targeted to locally specified needs. For example, Malaria: An On-Line Resource contains a step-by-step course in malaria diagnosis based on examination of thick and thin blood films. It also includes a primer on preparation of such films and online interactive tests to assess the skills of students who follow the training course.

The National Malaria Research Programme in Durban, South Africa, is exemplary for its information on malaria risk in southern Africa. This site can serve as a role model for the surveillance components of control programs. The malaria distribution maps presented at different scales of resolution are especially useful for planning resource allocation.

The Supercourse: Epidemiology, the Internet, and Global Health has online courses and a superb set of Internet links that could readily be adapted to serve the training needs of public health workers throughout the tropical regions of the world. Facilitating access to these Internet sites is, in my view, where substantial financial resources should be invested as part of a much more broadly gauged program supporting public health infrastructure. This translates into needed funds from donor countries (in the short run) to support computing and communication capability in developing countries. The payoff to improving the entire public health infrastructure in the tropics is potentially very large.