In the hidden corners of global health, a silent crisis reemerged while the world watched a single pandemic.
Imagine firefighters so focused on a blazing skyscraper that they fail to notice smaller fires reigniting throughout the city. This analogy captures the story of Neglected Tropical Diseases (NTDs) during the COVID-19 pandemic. As global health resources rapidly pivoted to confront SARS-CoV-2, many long-standing battles against lesser-known diseases lost crucial ground, creating a devastating ripple effect that continues to impact over one billion people worldwide 1 .
People affected by NTDs worldwide
Diseases classified as NTDs by WHO
Of global disease burden from NTDs
NTDs represent a group of chronic disabling diseases that primarily affect the world's most impoverished communities. These diseases, including dengue, chikungunya, leishmaniasis, and schistosomiasis, thrive in tropical regions and disproportionately impact those with limited access to clean water, sanitation, and healthcare. The World Health Organization had developed an ambitious road map to eliminate NTDs by 2030, but the COVID-19 pandemic dramatically disrupted these plans, leading to an alarming resurgence of these ancient scourges 1 .
The connection between these two health crises reveals much about the fragile interconnectedness of our global health systems. As one researcher noted, the pandemic "significantly impacted global socioeconomic and healthcare infrastructure over the past three years," creating perfect conditions for NTDs to resurge . This article explores how the COVID-19 pandemic reshaped the landscape of neglected tropical diseases, the innovative scientific responses being developed, and the path forward in managing these intersecting health challenges.
Neglected Tropical Diseases represent a diverse group of communicable diseases caused by pathogens including bacteria, viruses, fungi, and parasites. Many involve complex transmission cycles between humans, animals, and insect vectors, making their epidemiology particularly sensitive to disruptions in healthcare services 1 4 . The WHO currently lists 21 distinct conditions as NTDs, with Noma being added as recently as November 2023 .
NTDs predominantly affect marginalized populations in rural areas, urban slums, and conflict zones with limited healthcare access 4 .
NTDs receive insufficient research and development funding due to limited commercial prospects despite their significant global burden .
Mass drug administration programs for diseases like filariasis were severely interrupted as health systems redirected personnel, funding, and attention toward pandemic response 1 .
Critical medicines, diagnostic tools, and vector control materials faced global shortages as manufacturing and transportation networks were disrupted.
Vector control programs, community health worker initiatives, and vaccination campaigns were paused during lockdown periods.
Limited healthcare access during lockdowns meant many NTD cases went undiagnosed and untreated, creating reservoirs for future transmission.
| Disease | Pathogen Type | Region Affected | Impact During Pandemic |
|---|---|---|---|
| Marburg virus disease | Virus (Filovirus) | Ghana | Outbreak with ≈90% mortality rate |
| Dengue virus | Virus (Flavivirus) | North India | 77.58% of acute febrile illness cases |
| Bovine babesiosis | Parasite (Babesia bovis) | Tropical regions | Underestimated impact due to diverted resources |
| Dermatophytosis | Fungal infection | Nepal prisons | Prevalence exacerbated by crowded conditions |
| Zika virus | Virus (Flavivirus) | Americas | Continued transmission despite diverted resources |
The COVID-19 pandemic didn't just disrupt disease management—it also stimulated innovative research into NTD treatments. One compelling example comes from the battle against bovine babesiosis, a tick-borne parasitic disease that affects cattle in tropical and subtropical regions. Though often overlooked, this disease has significant economic impacts on agricultural communities already struggling with poverty.
A 2025 study conducted by Cardiollo and colleagues offers a revealing look at how comparative drug research may lead to more effective treatments for NTDs. The researchers designed an elegant experiment to compare the efficacy of two drugs—imidocarb dipropionate (ID) and buparvaquone (BPQ)—against the Texas T2Bo strain of Babesia bovis 4 .
The findings were striking: BPQ demonstrated superior efficacy by completely eliminating Babesia bovis parasites at 150 nM concentration, while ID required 300 nM to achieve the same effect 4 . This twofold increase in potency suggests BPQ could represent a more effective first-line treatment for global babesiosis control programs.
| Drug Compound | Concentration for Complete Parasite Elimination | Relative Efficacy | Potential Clinical Implications |
|---|---|---|---|
| Buparvaquone (BPQ) | 150 nM | 2x more effective than ID | Potential first-line treatment |
| Imidocarb dipropionate (ID) | 300 nM | Baseline efficacy | May be superseded by more effective alternatives |
The broader significance of this research extends far beyond bovine babesiosis. It exemplifies the type of targeted therapeutic development that remains critically needed for NTDs, even during global health emergencies. As the authors concluded, "BPQ was superior in efficacy to ID" 4 , highlighting how methodical comparative studies can identify optimal treatments even when resources are limited.
The simultaneous management of COVID-19 and NTDs required innovative approaches that balanced competing public health priorities. Interestingly, strategies developed for one disease sometimes offered insights for managing the other.
Healthcare systems in low-income countries struggled to allocate limited resources between the acute pandemic threat and persistent NTD burdens.
Both contexts highlighted the need for rapid, accurate diagnostics that could be deployed in resource-limited settings 8 .
Success depends on community adherence to preventive measures, whether for COVID-19 or NTD mass drug administration 6 .
| Strategy Type | COVID-19 Applications | NTD Applications | Key Differences |
|---|---|---|---|
| Vaccination | mRNA and viral vector vaccines with regular updates | Limited availability (only for some diseases like dengue) | Massive investment in COVID-19 vs. neglected NTD vaccine development |
| Drug Therapies | Antivirals (nirmatrelvir/ritonavir, remdesivir) | Repurposed drugs, natural compounds, protease inhibitors | Pharmaceutical industry engagement much higher for COVID-19 |
| Non-Pharmaceutical Interventions | Masking, social distancing, lockdowns | Vector control, improved sanitation, mass drug administration | COVID-19 measures temporary, NTD measures require sustained implementation |
| Diagnostic Testing | Rapid antigen tests, RT-PCR | Limited rapid tests, reliance on clinical presentation | Greater accessibility and innovation in COVID-19 diagnostics |
In the wake of the COVID-19 pandemic, research into NTDs has incorporated several innovative approaches that promise to accelerate progress toward the 2030 elimination goals.
Genomics, transcriptomics, and proteomics approaches allow researchers to identify potential drug targets by understanding pathogen biology and host-pathogen interactions 4 .
These systems enable rapid testing of thousands of compounds for activity against NTD pathogens, significantly accelerating drug discovery.
Carefully selected animal models that replicate human disease aspects are crucial for evaluating experimental treatments before clinical trials.
Computational tools that help researchers predict how small molecules might interact with protein targets, as seen in studies of V. cinerea compounds against dengue virus 4 .
The successful platform technologies used for COVID-19 vaccines—particularly mRNA and adenoviral vector systems—are now being adapted for NTDs. For chikungunya virus, a vaccine candidate using pre-membrane (prM) and envelope (E) glycoproteins has shown more than 90% efficacy in Phase I clinical trials 4 . Similarly, a recombinant yellow fever vaccine using the same proteins demonstrates comparable efficacy. For dengue, two vaccines (Dengvaxia® and Qdenga®) are already licensed for human use 4 .
For Zika virus, researchers have identified several promising candidates, including protein inhibitors such as LAS 52154459, LAS 52154463, and LAS 52154474, which efficiently contain the disease with low toxicity 4 .
Research into traditional medicinal plants has identified promising anti-NTD compounds from V. cinerea, with chrysoeriol emerging as the most effective agent against DENV-2 4 .
The application of omics approaches and computational tools represents perhaps the most promising frontier in NTD research. As Kafle and Ojha described, these include "genomics, transcriptomics, and proteomics" approaches 4 .
The authors observe that "Artificial Intelligence will be very helpful to accelerate NTD-related research and discovery of novel biologics with limited available funds" 4 , opening new avenues to combat infections like the carcinogenic human liver fluke Opisthorchis viverrini and other NTDs of global concern.
The re-emergence of neglected tropical diseases during the COVID-19 pandemic offers a sobering lesson in global health priorities. It reveals the fragility of hard-won gains against diseases of poverty when crisis strikes and highlights the interconnectedness of global health challenges. As we move forward, several principles must guide our approach:
Global health security requires attention to all threats, not just those making headlines. The "neglect" in neglected tropical diseases must become a historical footnote rather than a continuing reality.
Innovation born from the COVID-19 crisis—from mRNA vaccine platforms to decentralized clinical trials—must be applied to the NTD field.
The One Health approach—which recognizes the interconnection between human, animal, and environmental health—provides a promising framework for addressing NTDs .
Sustained progress will require addressing the social determinants that allow NTDs to persist: poverty, inadequate sanitation, limited healthcare access, and climate change .
The COVID-19 pandemic revealed both the vulnerabilities and resilience of our global health systems. As we build back, we have an opportunity to create more integrated, equitable approaches to health that leave no one behind—whether they face a novel coronavirus or ancient tropical diseases that have plagued humanity for centuries. The road to 2030 elimination targets may be steeper after the pandemic's disruptions, but with renewed commitment and innovative tools, it remains within reach.