Every year on January 30, communities around the world take stock of humanity’s struggle against the neglected tropical diseases (NTDs), a group of infectious diseases that primarily affect impoverished populations in tropical and subtropical regions of the world. In this blog post, Savanna Randi, MPH ‘23, a PhD candidate in the Cappello Lab in the Department of Epidemiology of Microbial Diseases, reflects on the impact of climate change on NTDs, and how she is applying the research skills she has acquired in epidemiology and mathematical modeling to advance the field.

Climate change has significantly reshaped our understanding and response to neglected tropical diseases (NTDs). Shifts in climate are creating more favorable conditions for the vectors that transmit many of these diseases. This poses a critical concern in regions such as sub-Saharan Africa where NTDs are already prevalent, compounding public health challenges and straining fragile healthcare systems–particularly in densely populated areas. Climate change can also drive forced migration by displacing populations fleeing the effects of rising sea levels, extreme weather events, and desertification. This not only threatens the health of migrating communities but also facilitates the spread and emergence of diseases in previously unaffected areas.

In my own research in Ghana, climate change is introducing new risk factors for soil-transmitted helminth (STH) infections–a subgroup of NTDs. Around 1.5 billion people are affected by STH worldwide, with hookworm alone infecting up to 500 million people. These infections can be devastating in regions with limited resources, reduced water, sanitation, and hygiene (WASH) capacity, and poor infrastructure. For example, increased humidity and precipitation can create optimal conditions for larval development and transmission dynamics and thereby influence infection rates. I have seen how increased rainfall can lead to severe flooding, which can then facilitate the distribution of hookworm eggs in the soil and increase exposure risk in high-traffic areas.

This mix of socioeconomic, behavioral, environmental, and climatic factors necessitates a comprehensive and locally adapted approach to STH infections. By integrating effective interventions, strengthening WASH infrastructure, and considering the broader impacts of climate change, I believe we can reduce the burden of NTDs and improve health outcomes among affected populations.

For several years, I have conducted epidemiological research on STH in close collaboration with a community in Ghana. Together, we are determining the local prevalence and distribution of hookworm infections, investigating specific host-parasite factors that enable these infections, and evaluating community responses to treatments.

In partnership with the University of Ghana, I am also assessing WASH infrastructure and investigating exposure risks by sampling the soil near water sources. Understanding how these environmental factors contribute to hookworm transmission can help guide local public health interventions. I am also developing screening tools for hookworm infections to better detect infections and inform targeted control strategies. Finally, I am exploring modeling methods to evaluate the effectiveness of existing control programs. While modeling prevalence estimates over time presents challenges, it is a critical step in understanding the dynamics of endemic diseases and determining the most effective strategies for sustainable control. My aim is to identify the limitations and improvement opportunities related to existing diagnostic capabilities and surveillance efforts.

Yale EMD has been instrumental in supporting this work by giving me access to interdisciplinary partnerships, invaluable mentoring, and rigorous training to prepare me to produce high-quality research. I am especially grateful for the opportunity to work alongside dedicated doctors and peers who are deeply committed to advancing global health and our incredible international partnerships.

In regions where NTDs are common, strengthening local economies and infrastructure is vital for sustaining disease control and resilience. To overcome challenges, it’s essential to work transparently with affected communities to ensure solutions are practical, acceptable, and inclusive of local people and healthcare facility staff, governmental agencies, and district officials.

The study of NTDs can be challenging, as there is no "silver bullet." However, I encourage public health professionals and scientists to find inspiration and motivation in the abundant opportunities for discovery in this field. It is through collaborative engagement across disciplines that we can drive meaningful and lasting change.