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The first step in treating an infectious disease outbreak or slowing down an epidemic is finding affected individuals. Yet decades into the course of epidemics that ravage underprivileged areas, adequate diagnostic tests are still sorely missing. When tests exist, they are often ill-adapted for areas where resources and trained staff are limited.

Presently, screening for tuberculosis infection is still done by microscopic examination of sputum, which is 40–60% sensitive in the best cases. It takes several days to get the results, and the test cannot be performed at the point of care in isolated rural areas. As a consequence, even this poorly performing test is beyond the reach of the majority of tuberculosis patients. In a Commentary on page 887, Robert Grant discusses the methodological needs in resource-poor regions for diagnostic and patient monitoring, in the context of tuberculosis and HIV/AIDS epidemics. The same recurring themes apply to many so-called neglected diseases such as malaria and sleeping sickness.

Research ongoing at the cutting edge of technological sophistication could find important applications in low-tech solutions for point-of-care diagnostics. For example, progress in microfluidics may lead to integrated, disposable analysis devices that could be manufactured at reasonable cost and used by staff with little medical or laboratory training. Studies on nanoparticles may generate new, robust colorimetric tests that could be applied to detect infection by revealing the presence of a microbial protein or an antibody against a pathogen. Isothermal nucleic acid amplification may provide molecular assays requiring only simple instrumentation. More examples of elaborate technologies that could lead to innovative low-tech solutions adapted to field work are presented in the Commentary (p. 887) and in a Research Highlight (p. 882).

In the budgets of funding agencies and philanthropic organizations, diagnostics occupy only a tiny fraction of the investment needed to address poverty-related diseases. For example, in the European Research Program on HIV/AIDS, malaria and tuberculosis, funded under the European Union 6th Framework Program (2002–2006), diagnostics received only 3% of the allocated budget, compared to 48% and 49% for treatment and prophylactic research, respectively. Whether this exact distribution is adequate is debatable, but it seems realistic that a relatively small investment in diagnostic development could go a long way. The Stop TB Partnership, a network of 500 international organizations that has issued a Global Plan aiming at a tuberculosis-free world by 2050, has evaluated the financial needs for development of new diagnostics over the 2006–2015 period as $0.5 billion. This constitutes only 5.5% of the research and development needs of the Global Plan to Stop TB, or 0.9% of its total needs.

Though representing such a small fraction of the investment, new diagnostic development could have major positive implications—not only because the ability to determine who is infected is a prerequisite to treatment, but also because for several infectious diseases such tests are needed to guide treatment and avoid promoting drug resistance. In addition, appropriate diagnosis and monitoring tests are needed to enable clinical trials for new treatments, which are more meaningful if they are conducted locally, and to permit epidemiology studies that can help predict the progress of disease.

So the question becomes, who should develop these tests? On one hand, there is no business model to speak of to justify investment by commercial companies. For diseases like sleeping sickness that affect exclusively the poorest areas, the perspective of low return on investment discourages companies from committing the large sums of money necessary to commercialize a test. For diseases that also affect the industrialized world, such as HIV/AIDS, the diagnostic industry tends to favor high-technology solutions that can only be implemented in well-resourced laboratories.

On the other hand, the academic world is ill-equipped to develop the needed tests. First, developing a test and its proof-of-principle application, even making it work for routine use in the research lab, is one thing. Getting the same test to graduate to an assay that can be used reliably to diagnose disease—let alone diagnose disease in conditions of resource and staff shortage—is a different matter. Although this assay development process is the daily preoccupation of many industry scientists, academic researchers lack expertise in this area, and universities do not have the necessary resources. Second, the academic culture, by defining achievement in terms of high-profile papers and patents, focuses on conceptual innovation and does not offer incentives for researchers to do the nitty-gritty job of product development.

The answer probably lies somewhere in between, and a path for progress has been blazed over the past 10 years by emerging private-public partnerships. Several not-for-profit partnerships have been created to facilitate the discovery and development of new drugs for neglected diseases—for example, the TB Alliance and the Institute for OneWorld Health. They negotiate intellectual property rights on 'unprofitable' leads and contract drug development to the private and public sectors. Again, diagnostics represent only a small proportion of their activities.

A notable exception is the Foundation for Innovative Diagnostics (FIND) based in Geneva, which is entirely dedicated to developing new diagnostics and focuses its efforts on tuberculosis, malaria and sleeping sickness. In September, FIND received a $62 million grant from the Bill and Melinda Gates Foundation, and it has previously benefited from other donations, notably from the Dutch government. The foundation applies a business-like approach to diagnostic development, complete with ISO13485 certification and membership in the European Diagnostic Manufacturers Association, while considering implementation issues specific to resource-poor settings throughout the development pipeline.

Such a private-public partnership approach makes sense as a means to develop and deliver quality products, but it still relies on funding from governments and philanthropic organizations. Similarly, the fundamental research it draws on to generate innovative solutions is in need of funding. Even if this challenge appears smaller than that of finding drugs, developing adequate diagnostics for poverty-related diseases will require just as much creative energy and focus. It may also have an equally important impact on the quality of life of millions of people.

This article is part of the Global Theme on Poverty and Human Development, organized by the Council of Science Editors. All articles from the Nature Publishing Group are available free at http://www.nature.com/povhumdev. The content from all participating journals can be found at http://www.councilscienceeditors.org/globalthemeissue.cfm.