One Health and NTDs—A unified approach to eliminate neglected tropical diseases in India

The world is at a tipping point where now, more than ever before, human, animal, and ecological health are intricately linked and impacting each other. Zoonotic diseases, representing 65 per cent of new and recent global outbreaks, highlight the need to tackle the interacting system of humans, animals, and the environment. Moreover, climate-driven vector-borne diseases are responsible for more than 17 per cent of all infections, leading to more than 700,000 annual deaths globally. These challenges highlight the critical need to comprehensively understand environmental, animal, and vector reservoirs to develop an adaptive healthcare system—particularly in the context of Neglected Tropical Diseases (NTDs).

NTDs, a group of 21 debilitating infectious diseases, affect over 1 billion people globally, causing significant morbidity, disability, and death. These diseases, including visceral leishmaniasis (VL), lymphatic filariasis (LF), and dengue, are often vector-borne, zoonotic, and environmentally driven. Their complex epidemiology calls for an integrated approach—One Health—that addresses human, animal, and environmental health through collaborative and interdisciplinary efforts.

Why Adopt the One Health Approach?

The One Health approach is founded on the premise that human, animal, and environmental health are inextricably linked. This approach is highly important to the successful prevention and cure of NTDs for the following reasons. Firstly, a significant number of the NTDs are zoonotic, i.e., animals play a critical role in spreading them. For example, both rabies and visceral leishmaniasis (VL) are diseases that can be transmitted from animals to humans, and managing the animal populations that carry the diseases is crucial in controlling human cases.

Second, environmental factors significantly influence disease transmission. For example, climate change impacts vector-borne diseases like malaria and dengue and alters the breeding grounds and behaviour of mosquitoes. One Health promotes an integrative view and study of such environmental effects and, thus, more focused interventions.

Third, the approach encourages coordinated surveillance among human, animal and environmental health agencies, thereby facilitating early detection and rapid response to outbreaks. It is also critical to avoid a resurgence of the disease in endemic areas through continuous entomological studies. Lastly, One Health is a cost-effective approach that leverages multisectoral synergy to optimize resource utilization. It provides a holistic framework to address the multidisciplinary challenges of NTDs.

Ground-Level Work: One Health Implementation in the Real World

India has made significant progress in eliminating neglected tropical diseases (NTDs), with visceral leishmaniasis (VL) cases dropping by 95per cent since 2014. The country is on track to earn WHO certification for eliminating Kala-azar, having reduced cases to less than one per 10,000 population. India has also successfully eliminated guinea worm disease, yaws, and trachoma in 2000, 2016 and 2024 respectively. However, diseases like Lymphatic Filariasis (LF), Dengue and Rabies continue to pose a significant public health challenge, which can only be addressed through an integrated approach.

For the elimination of lymphatic filariasis (LF), of which India accounts for nearly 40per cent of the global burden, we follow a five-pronged strategy: biannual Mass Drug Administration (MDA), Morbidity Management and Disability Prevention (MMDP), strengthened vector control, inter-sectoral convergence, and a focus on innovative approaches across the board. While the introduction of ivermectin has shown promising results, achieving high drug uptake during MDA is crucial for the new drug regimen to be effective. For this, extensive block-level training of health officials and drug administrators is needed to ensure successful implementation. Additionally, integrating the treatment/management of lymphoedema and elephantiasis within the existing health system is vital to provide sustained care.

Tackling dengue requires an integrated approach that includes enhanced vector control, a focus on water, sanitation, and hygiene (WASH), addressing environmental factors, and utilizing available vaccines for prevention. The introduction of new dengue vaccines and the anticipated development of additional options offer hope, but adequate financing and effective distribution will be essential for success. For rabies, challenges persist in ensuring vaccine affordability and accessibility, especially in remote areas. A strong supply chain and effective strategies for managing stray dog populations are crucial to maintaining progress.

Moreover, even as India approaches the cusp of VL elimination, we must not get complacent. Our neighbour Nepal has seen the disease spread from endemic to non-endemic areas. Additionally, post-kala-azar dermal leishmaniasis (PKDL) and HIV co-infections are challenging, posing a persistent risk of VL resurgence due to the high number of parasites in the skin lesions of infected persons. This further reinforces the need for robust surveillance and strong vector control measures.

The foundation built to combat these NTDs can be strengthened through the One Health approach, integrating human, animal, and environmental health to address these diseases more holistically. In research and development, the collaboration between the Indian Council of Medical Research (ICMR) and the Indian Council of Agricultural Research (ICAR) has been instrumental in advancing zoonotic disease research for VL and rabies, focusing on understanding cross-species disease transmission. This partnership is vital for controlling zoonotic spillovers and preventing human outbreaks.

For effective vector control, the National Centre for Vector Borne Diseases Control (NCVBDC) employs Integrated Vector Management (IVM) strategies, considering human and animal health data. This integrated approach helps to optimize control measures for diseases like malaria, dengue, and chikungunya, targeting local conditions and host interactions.

India has shown effective collaboration across sectors at the community level. Across endemic states, the Ministry of Health, in partnership with the Ministries of Rural Development, Panchayati Raj, Agriculture, Youth Affairs, and others, has implemented various initiatives that have enabled the nation to achieve over 94per cent participation from the eligible population in Mass Drug Administration (MDA) of anti-filarial medicines. This extensive collaboration has been instrumental in reducing lymphatic filariasis transmission.

Additionally, the mapping of and subsequent outreach to Krishi Vigyan Kendras (KVKs) across Uttar Pradesh, Bihar, and Jharkhand has helped the LF elimination program to engage million farmers in the MDA rounds and for disease prevention education. By linking agriculture with health, this initiative addresses environmental and animal-related factors contributing to NTD transmission.

These examples demonstrate the power of the One Health approach in real-world applications, showcasing how integrated efforts across sectors can effectively reduce the burden of NTDs. Continued strengthening of community participation through coordinated knowledge dissemination, strategic outreach, and treatment incentives will play a crucial role in sustaining our NTD elimination efforts.

Future of One Health in NTD Elimination

While India continues to refine its strategies for combating NTDs, integrating health impact assessments into development priorities will be crucial for reducing exposure to environmental risk factors. Proactive measures, such as climate adaptation plans and increased investment in disease surveillance and capacity building, will significantly improve early detection and response, particularly in rural and remote areas. If we are to achieve WHO’s 2030 target of reducing the number of people needing NTD treatments by 90per cent, we must stay consistently vigilant.

The Kigali Declaration, a global commitment to end NTDs made in June 2022, specifically called for “sustaining a multisectoral and multidisciplinary approach to tackling NTDs, including One Health, that recognises the interactions of human, animal and environmental health and mitigates against the impact of climate change on NTDs.” With this approach, India is poised to strengthen its healthcare infrastructure, accelerate progress toward NTD elimination, and ensure equitable health outcomes for all, including the most marginalized communities building on its successes even more. By fostering research, innovation, and intersectoral collaboration, India is on a clear path to achieving lasting success in the fight against NTDs.

This article is written by Dr. N.K. Ganguly, Former Director General Indian Council of Medical Research (ICMR).

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