Bridging the Diagnostic Gap: WHO’s Battle Against Neglected Tropical Diseases

The sixth meeting of the WHO Diagnostic Technical Advisory Group for Neglected Tropical Diseases underscored the urgent need for improved diagnostics to combat NTDs. Key discussions focused on the progress and challenges in developing diagnostic tools for diseases like lymphatic filariasis and visceral leishmaniasis. The meeting highlighted innovative cross-cutting initiatives, such as the development of a biobank and an NTD diagnostic portal, and concluded with recommendations to accelerate diagnostic development and deployment.

Geneva, Switzerland - In a determined effort to address the diagnostic challenges of neglected tropical diseases (NTDs), the World Health Organization (WHO) recently convened its sixth Diagnostic Technical Advisory Group (DTAG) meeting. This gathering, held on February 14-15, 2024, brought together experts from around the globe to discuss and strategize on improving diagnostic tools for these often-overlooked diseases. The outcomes of this meeting could shape the future of global health, particularly for regions plagued by NTDs.

The Urgent Need for Better Diagnostics

Neglected tropical diseases affect over a billion people worldwide, predominantly in low-income countries. These diseases, which include ailments like lymphatic filariasis, visceral leishmaniasis, and schistosomiasis, impose a heavy burden on communities and health systems. Effective diagnosis is crucial for controlling and eventually eradicating these diseases, but it remains a significant challenge due to the lack of reliable, accessible diagnostic tools.

At the heart of the discussions during the DTAG meeting was the need for improved diagnostics. WHO's roadmap for NTDs from 2021-2030 emphasizes the development of new tools and technologies to meet diverse epidemiological and diagnostic challenges. The DTAG plays a pivotal role in this by identifying and prioritizing diagnostic needs, defining evaluation processes for new tests, and informing WHO’s strategies on diagnostics.

Breakthroughs and Challenges

The meeting highlighted several breakthroughs and ongoing challenges in the field of NTD diagnostics. For lymphatic filariasis (LF), significant progress was reported in both laboratory and field evaluations of new diagnostic tests. Despite the absence of a gold standard reference test, field evaluations in Samoa, Sierra Leone, and India showed promising results. Similar advancements were noted for visceral leishmaniasis (VL), where efforts are focused on evaluating rapid diagnostic tests based on antibody detection.

However, these advancements are not without challenges. The lack of standard reference panels for laboratory evaluations and the variability in country-specific processes and timelines pose significant obstacles. The meeting underscored the importance of establishing clear use cases for diagnostic tests and developing a robust framework for monitoring and evaluation.

Cross-cutting efforts and Innovations

Several cross-cutting initiatives were also discussed during the meeting. One notable area of focus was the development of a biobank and an NTD diagnostic portal. These initiatives aim to enhance the visibility of the diagnostic landscape for NTDs and maximize the use of existing resources. The DxConnect Virtual Biobank (VBB), for instance, provides a global view of sample collections from various institutions, promoting transparency and efficiency in developing diagnostic tools.

Another critical area is the development of reference standards for new NTD diagnostic tests. The WHO is working on synthesizing evidence into recommendations for evaluating the sensitivity and specificity of these tests. This effort is crucial for ensuring that new diagnostics meet the required performance standards and are fit for purpose.

The meeting also addressed the urgent need for validated tests for dengue, given the severe outbreaks affecting multiple regions. With over 6 million cases and 7000 deaths reported since 2023, the development of reliable in-vitro diagnostics for dengue is a top priority.

Moving Forward: Recommendations and Next Steps

The DTAG meeting concluded with several key recommendations aimed at accelerating the development and deployment of diagnostic tools for NTDs. These include.

Expediting the ERPD process for dengue diagnostics.

Developing standard operating procedures for harmonizing laboratory and field evaluations.

Exploring the establishment of WHO-supported biobanks in collaboration with FIND and WHO Collaborating Centres.

Moreover, the meeting emphasized the need for ongoing collaboration and strategic resource mobilization. The advocacy and resource mobilization subgroup highlighted the importance of mapping and coordinating the donor landscape to meet the needs on the ground.

In his closing remarks, Professor Patrick Lammie, Chair of the DTAG, stressed the critical role of diagnostics in achieving the WHO's 2030 targets for NTDs. He urged participants to reflect on the discussions and identify actionable steps to expedite the development and implementation of diagnostic tools.