World Neglected Tropical Diseases (NTDs) Day is celebrated on January 30 every year and this year the World Health Organization (WHO) urged governments, leaders, communities and individuals to unite, act and eliminate these diseases through "bold, sustainable investments." 

Neglected Tropical Diseases (NTDs) are a group of 21 infectious diseases that primarily impact over a billion people living in poverty across the globe. India experiences the world’s absolute burden of at least 11 NTDs, including hookworm, dengue, lymphatic filariasis, leprosy, kala-azar, and rabies, representing the highest number of cases worldwide.  

These diseases often cause severe disabilities and can persist for long periods. Due to poverty and limited access to resources, millions of people in India are vulnerable to NTDs. 

India's Neglected Tropical Diseases burden, and the progress made 

India has had some success in eliminating certain NTDs; for instance, we successfully eradicated trachoma, a potentially blinding eye infection, in all 27 high-risk districts across 23 states and Union Territories by 2017. Similarly, yaws and guinea worm were also eliminated. 

However, other NTDs such as dengue, kala-azar, chikungunya, leprosy and lymphatic filariasis, among other, continue to pose a significant health burden on some of the most disadvantaged communities in India.  

Dengue remains a significant public health issue. Unlike some other NTDs, dengue is caused by a virus and has four different strains circulating in India. The burden of Dengue increased from about 1.6 lakh cases and 166 deaths in 2019, to 2.9 lakh cases and 485 deaths in 2023.  

Prof Ganguly shared that Takeda dengue vaccine has recently been introduced in India, and vaccines from Bharat Biotech (Dengvaxia) and Serum Institute of India are expected to be available soon. These vaccines could help in managing the disease burden. 

Chikungunya, another viral disease, resurges in different parts of the country.  

"The main concern with chikungunya is severe arthritis, which can cause long-term disability. While a vaccine was developed in France and later acquired by Walter Reed Institute, it has not been commercially viable due to the disease’s irregular occurrence," he explained. 

Rabies remains a major issue in many parts of the world, especially in rural communities. Dog bites and scratches are responsible for 99 per cent of human rabies cases, but they can be prevented through dog vaccination and bite prevention. The WHO factsheet says that if the virus reaches the central nervous system and symptoms develop, rabies is fatal in 100% cases. "This is mainly because many people in affected regions do not have access to vaccines," Prof Ganguly confirmed.  

Lymphatic Fialriasis, commonly known as elephantiasis, is also a persistent issue. As of 2020, the Indian government had told parliament that the country contributes to about 40% of all Lymphatic Filariasis in the world, and is "endemic in 257 districts of 16 States and 5 Union Territories(UTs) and about 650 million people in these States/UTs are at risk of developing it." By 2024, data shows that the cases were being reported in "345 districts across 20 states and union territories." The National Health Policy of 2002 had said they would eliminate the disease in India by 2015, and then later extended it to 2021. The government has now set 2027 as the target year for elimination of Lymphatic Filariasis; about three years ahead of the global target. 

In other cases, for instance, kala-azar, cases have dropped significantly, but is yet to be eradicated completely. India had aimed to eliminate Kala-azar, also known as visceral leishmaniasis, a life-threatening parasitic disease, by 2023. However, government data shows that while the number of cases have dropped significantly since 2014, there were still 438 cases, and 2 deaths in 2024. Bihar  had the highest case load, with 242 cases.  

"Kala-azar cases have significantly declined, but challenges remain [because of the problem of re-occurrence]," said Prof Nirmal Kumar Ganguly, the former Director General of the Indian Council of Medical Research (ICMR) said, while stressing that stronger global efforts are needed to increase awareness, funding, and access to treatment for NTDs.  

"One key challenge is post-kala-azar dermal leishmaniasis (PKDL) [a skin condition that can develop after a person recovers from kala-azar]. In many cases, PKDL appears as patchy skin lesions, which are often ignored or misdiagnosed." he added, highlighting how one disease could be feeding another making elimination of NTDs all the more difficult. 

Dr Kavita Singh, Director, South Asia, Drugs for Neglected Diseases initiative (DNDi) shared that research conducted by DNDi in India has shown that PKDL occurs in 3-5 per cent of patients who have recovered from Kala Azar.  

Prof Ganguly emphasized the need for continued active surveillance in both endemic and non-endemic areas, citing Nepal's experience as an example. "Surveillance must remain active for at least four years, followed by a strong sentinel surveillance system to sustain progress," he stressed. 

According to him, India is working on a new vaccine for leishmaniasis in collaboration with researchers from the U.S. Food and Drug Administration (FDA). The vaccine is currently undergoing regulatory approval and could become an important tool in eliminating the disease, and the associated issues. 

India has also made progress in reducing leprosy cases, but challenges remain. Leprosy has a patchy distribution, meaning some regions still report significant cases, experts say. 

Has climate change influenced the epidemiology and spread of Neglected Tropical Diseases in India? 

Shifting weather patterns—temperature, rainfall, and humidity—are causing neglected tropical diseases (NTDs) to spread into new regions. Meanwhile, previously controlled diseases are making a comeback.  

"Many NTDs are vector-borne or water-borne at the forefront of the climate-sensitive diseases list. Dengue fever, for example, is spreading fast not only in India but to all continents," Dr Singh of DNDi said.  

She explained that rising temperatures due to climate change will lead to increases in vector development rate and, biting frequency- leading to longer transmission seasons and increased incidence of dengue, not only in endemic areas , but also greater spread in areas of lower transmission.  

Way Forward 

The Indian government has identified NTDs as a priority, setting elimination targets for 2015, 2018, 2020, and now 2030. However, a structured, systemic approach to their eradication has been lacking, studies suggest. 

In August 2023, the then Union Health Minister Mansukh Mandaviya inaugurated the second phase of the annual Nationwide Mass Drug Administration (MDA) initiative for Lymphatic Filariasis  India, which was committed to eliminating Lymphatic Filariasis by 2027 

However, Prof Ganguly said that the delays in elimination of NTDs have been because of poor community participation and low compliance.  

Dr Kavita Singh notes that while the focus remains on diseases such as kala azar and lymphatic filariasis—both seemingly close to elimination—sustained attention and adaptable strategies will be essential to achieving and maintaining these targets. 

"Global NTD programmes continue to face several challenges [in terms of] funding gaps and changing financial landscapes," WHO has acknowledged. 

"While the goal of eliminating NTDs by 2030 is ambitious, it is achievable with the right combination of strong political will, resources, and coordinated efforts across multiple sectors," Dr Singh said. 

Also read: 2024: India marks major milestone in eliminating Neglected Tropical Diseases - First Check