Neglected Tropical Diseases: A Blind Spot in Global Healthcare

Jan 30 is observed as World NTD Day

Meaning and History

Neglected Tropical Diseases (NTDs) encompass a diverse group of infections primarily affecting impoverished populations in tropical and subtropical regions. Historically, these diseases have been overlooked in global health agendas due to their association with poverty and their often asymptomatic nature, which masks their impact on communities. The term ‘neglected’ reflects the lack of attention and resources allocated to combat these diseases compared to more prominent health issues like HIV/AIDS, tuberculosis, and malaria.

The recognition of NTDs began to gain momentum in the 2010s, particularly with the inclusion of targets related to these diseases in the Sustainable Development Goals (SDGs) established in 2015. The WHO’s NTD roadmap for 2021-2030 aims for significant reductions in the burden of these diseases through integrated health approaches.

Spread and Epidemiology

NTDs are primarily spread through poor hygiene, inadequate sanitation, and vector-borne transmission. Environmental factors such as climate change and urbanization further exacerbate their spread. They are prevalent in regions where people live in close proximity to disease vectors and reservoirs, such as water bodies that harbor parasites or insects like mosquitoes.

The complex life cycles of many NTD pathogens complicate public health interventions. For instance, diseases like schistosomiasis and lymphatic filariasis require specific environmental conditions for transmission, making control efforts challenging. The WHO estimates that over 1 billion people are affected by NTDs globally, with an additional 1.6 billion requiring interventions.

Types of Neglected Tropical Diseases

Some notable examples of NTDs include:

1. Schistosomiasis: Caused by parasitic worms; affects over 200 million people globally.
2. Dengue Fever: A viral infection transmitted by mosquitoes; increasingly prevalent due to climate change.
3. Leprosy: A chronic bacterial infection that can lead to severe disability if untreated.
4. Chagas Disease: Transmitted by triatomine bugs; affects millions in Latin America.
5. Lymphatic Filariasis: Causes significant morbidity through lymphatic system damage.

These diseases not only lead to physical suffering but also impose substantial economic burdens on affected communities due to healthcare costs and lost productivity.

The Disease Burden of NTDs in India

Being a tropical country, NTDs represent a significant public health challenge in India, where the burden is among the highest globally. Our country accounts for a substantial proportion of cases for several major NTDs, impacting millions of people, particularly in impoverished communities. India has the largest absolute burden of at least ten major NTDs, including: Dengue Fever, Lymphatic Filariasis, Leprosy, Visceral Leishmaniasis (Kala-azar), Rabies, Hookworm Disease, Ascariasis, Trichuriasis, Cysticercosis, and Trachoma.

Over 670 million people in India are at risk for infections caused by Wuchereria bancrofti and Brugia malayi, which are responsible for lymphatic filariasis. The country also reports nearly half of the global cases of visceral leishmaniasis and dengue.

The high burden of NTDs in India has profound implications:

1. NTDs contribute to morbidity and mortality, affecting productivity and quality of life in affected populations.
2. The consequent economic burden extends beyond healthcare costs to include lost income and reduced educational opportunities due to illness.
3. This disease burden signifies a parallel social burden, as it largely lies at the intersection of socio-economic and educationally backward communities. 

Challenges in Monitoring and Control in India

1. Only a few NTDs like dengue, rabies, snakebite, and leprosy are classified as notifiable diseases, making it difficult to assess the true burden of NTDs in India.
2. The prevalence of NTDs is unevenly distributed throughout the country, heavily concentrated in areas of urban and rural poverty.
3. India’s inability to achieve set targets on account of several factors has resulted in  multiple targets being set for NTD elimination over the years. Initially aimed for 2015, then 2018 and 2020, the latest target is now set for 2030. 

Government Initiatives

The Indian government’s strategies to eliminate NTDs includes:

1. Mass Drug Administration (MDA) programs: where drugs are provided at no cost to large populations, targeting diseases like lymphatic filariasis and soil-transmitted helminths. Approximately three-quarters of children needing deworming have received treatment.
2. Vector Control Programs: Initiatives by the National Centre for Vector Borne Disease Control aim to eliminate vector-borne diseases through prevention strategies.

Despite some progress, many NTDs still lack effective treatments or vaccines. This situation underscores the need for increased global attention and resources dedicated to combating these diseases.

A Blind Spot

NTDs have been a healthcare blindspot also because the pharmaceutical industry’s response has historically been limited. Factors contributing to this neglect include:

1. Low Profitability, as many NTDs primarily affect low-income populations, making them less attractive for pharmaceutical investment.
2. Minimal public awareness and advocacy for NTDs compared to other diseases.
3. Research into treatments and vaccines for NTDs has lagged behind more prominent diseases due to insufficient funding and prioritization.

Implications of the Neglect

This neglect of NTDs has had serious implications for global health equity. Continued prevalence of these diseases perpetuates cycles of poverty, social stigma, and exclusion. As a result, affected individuals often face discrimination, reduced educational opportunities, and diminished quality of life. Furthermore, the lack of effective interventions can lead to increased morbidity and mortality rates within vulnerable populations.

The Way Forward

At the global level, SDG Target 3.3 calls on global collaboration to “[E]nd the epidemics of AIDS, tuberculosis, malaria and neglected tropical diseases and combat hepatitis, water-borne diseases and other communicable diseases”. Several G20 countries have also committed resources to combat NTDs, emphasizing the importance of sustained funding for research, drug development, and public health interventions. These resources, especially financial, must be sustainable and not put a disproportionate burden on the developing countries in the form of future debt servicing liabilities. 

Partnerships between governments, NGOs, and international organizations – which by themselves fall under SDG 17 – must aim to enhance the effectiveness of interventions through shared resources and expertise.

At the domestic and local levels, traditional medicine and alternative medicine systems (AYUSH: Ayurveda, Yoga & Naturopathy, Unani, Siddha, and Homeopathy) ought to be leveraged, given their accessibility, affordability and cultural acceptance. For the most part, these systems of medicines use herbal remedies which are locally available, and hence possess a greater propensity to treat tropical pathogens. For example, Atractylodes lancea has shown potential against cholangiocarcinoma and may be explored for broader applications. This approach has been recognized and encouraged by the WHO’s Traditional Medicine Strategy as well. 

Conclusion

To summarize, the persistent neglect of tropical diseases represents a glaring inequity in global healthcare, disproportionately affecting vulnerable populations and perpetuating cycles of poverty and marginalization. Despite recent advancements, significant challenges remain in combating these diseases, particularly in India, where the burden is among the highest in the world. Addressing this blind spot requires a comprehensive, multi-stakeholder approach involving international collaboration, sustained funding, innovative research, and grassroots public health initiatives. Leveraging traditional medicine alongside modern biomedical strategies can further enhance the reach and effectiveness of interventions. Prioritizing neglected tropical diseases within global and national health agendas is not only a moral imperative but also a critical step toward achieving universal health coverage, reducing health disparities, and fostering sustainable development. The path forward demands collective action, political will, and a commitment to leaving no one behind in the pursuit of health equity.

References:

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