Keeping Targets in Sight with New Diagnostics for NTDs

By Kerry Gallo, Communications Officer, PATH

In 2012, the private and public sectors pledged substantial resources to fight neglected tropical diseases (NTDs) through the signing of the London Declaration. Donations of drugs from the pharmaceutical industry, funding from donors, and supportive policy at the international and national levels are helping to expand the toolkit for combating NTDs.

But important tools are still missing—diagnostic tests to guide efforts to control and eliminate NTDs.

The lack of effective diagnostics has been identified as a critical gap in the ability to achieve the goals set forward by the London Declaration. The NTD community has taken notice of this gap, as evidenced by new support to PATH for the prioritization and development of novel NTD diagnostic tests, which once commercialized, will be critical in the global fight against NTDs.

In many parts of the world, diagnostics are often taken for granted. But in low-resource settings, these tests are a rarity. People living in remote communities may be far from hospitals and clinics where tests are available, trained health workers who know how to properly administer complex diagnostics are often in short supply and there are few facilities where samples can be processed.

These are some of the challenges that the next generation of diagnostics for NTDs will need to overcome.

Diagnostics for NTDs are especially important because they provide data for informed decision-making throughout the life cycle of a control or elimination program. At the start of an NTD control or elimination program, diagnostics are critical to mapping disease and identifying areas in need of treatment. Interventions like mass drug administration (MDA) are the arrows in the NTD program manager’s quiver and diagnostics bring the target into focus so programs know where to aim. Even if current diagnostics are sufficient for this purpose, the need for new tests comes as NTD programs make progress on the path toward disease control and elimination.

Later on during the program life cycle, as MDA programs and prevention efforts are scaled up, levels of infection will decrease. However, current diagnostics for NTDs are not sensitive enough to detect very low levels of infection. Data from insufficiently sensitive tests might result in decisions to reduce or stop MDA prematurely, which can lead to infection levels bouncing back. New, more sensitive diagnostics will be critical to guide control programs for diseases such as soil-transmitted helminthiasis as MDA is scaled up globally.

New diagnostics will also be critical to conducting surveillance for elimination programs for diseases like onchocerciasis, blinding trachoma, lymphatic filariasis, Chagas disease, human African trypanosomiasis (sleeping sickness), leprosy and visceral leishmaniasis. Identifying individual cases of infection will become more challenging as levels decrease, requiring many samples from target populations to be taken. For this reason, simple, effective and field-ready diagnostics that can be used by minimally-trained staff with limited resources will be essential.

In the coming months, PATH and our partners will be working to identify where the introduction and scale-up of new diagnostics will have the greatest impact, evaluate potential technologies and focus on the most promising new tests. Continued commitment from donors and partners will be essential to bring these tests to market so they will be available for NTD program managers worldwide. Some progress has already been made—we worked to develop a new test for onchocerciasis, which will be available in late 2014.

With new diagnostics to hone our vision and guide our decisions, we will move closer to a future free of NTDs.

For more information, contact dxinfo@path.org.

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