By Henry Rosenbloom
During the 2024 rainy season in Kenya, catastrophic rainfall left people vulnerable to neglected tropical diseases. From May to June, Kenya’s ‘long rain’ season, parts of the country – including Nairobi – saw as much as 200% of the average in central regions and some Rift Valley areas seeing more than double the usual rainfall.
While acute damage from the bombardment of rainfall led to several days of flooding, more than 300 deaths, and thousands of displacements, long term significance of the unprecedented flooding could become a far more alarming development.
As regional sea temperatures rise in the Indian ocean because of climate change, extreme weather events in East Africa like the historic heavy rainfall increase in frequency.
Human activities – burning fossil fuels and changes in land use – release greenhouse gasses like carbon dioxide and methane that trap heat in the atmosphere, warming the planet, according to the Intergovernmental Panel on Climate Change (IPCC).
“Africa is and will be the center of multiple severe impacts of global warming,” warns Dr. Githinji Gitahi of Amref Health Africa.
“African populations are disproportionately affected by climate change, compounding the health risks already facing local populations, and aggravating the pressures on an already suboptimal health system. This, despite the fact that Africa only contributes 4 percent of global emissions responsible for climate change.”
As Dr. Gitahi theorizes, the rising intensity of extreme weather in the region brings to light a stark reality: for communities already grappling with neglected tropical diseases, these types of alarming new weather patterns are more than natural disasters; they’re a catalyst for further disease spread.
The heavy rains flooded sanitation infrastructure making the spread of disease like schistosomiasis and soil-transmitted helminths more likely. The flow of displaced families make it more difficult to contain outbreaks and further disrupt regular programming for neglected tropical diseases.
“Extreme weather events intensified by climate change disrupt healthcare infrastructure, hinder the delivery of essential neglected tropical diseases interventions, and strain already limited resources,” as reported by a recent study by the END Fund and Panorama Strategies.
“As these disruptions to healthcare systems and socioeconomic development increasingly occur simultaneously, the challenges faced by communities already burdened by the health and socioeconomic ramifications of neglected tropical diseases will intensify.”
In Ethiopia, these changing weather patterns have led to consecutive years of below average rainfall increasing the spread of visceral leishmaniasis, another neglected tropical disease.
In the spring of 2023, Berkede, a member of the Mursi tribe – a nomadic community that straddles the border between Ethiopia and South Sudan – was admitted to a field clinic in southwestern Ethiopia to treat a potentially deadly case of visceral leishmaniasis.
Berkede was part of a wave of new cases of visceral leishmaniasis in the area. Normally the region may see a handful of cases a year, but in 2023 there were hundreds. The small one room clinic housed up to 25 people at a time, many in critical condition.
Visceral leishmaniasis invades the blood system, attacking every organ in its path. It causes fevers, fatigue, and uncontrollable bleeding, and it destroys the immune system. If left untreated, it is deadly.
The visceral leishmaniasis parasite, spreads from sand flies that live near giant termite mounds, common to the arid lowlands of the South Omo region in southwestern Ethiopia. The climate change fueled drought in the region is causing malnutrition. The weakened immune systems from malnourishment makes it more difficult for the body to fight off a visceral leishmaniasis infection.
And as nomadic communities like Berkede’s move to follow the rains in search of ever-shrinking grazing for their livestock, they come in closer proximity to visceral leishmaniasis endemic territories.
The World Health Organization’s recently published “Climate change, malaria and neglected tropical diseases: a scoping review,” underlining the challenge, noting, “Climate change will perturb human health in profound and long-lasting ways, both directly and indirectly … There is already empirical evidence of climate change having amplified more than one half of all known human infectious diseases.”
At this early stage in our understanding, part of the issue is that research into the intersection of climate change and neglected tropical diseases – particularly climate sensitive diseases – is a profound lack of research, especially in Africa.
“What [climate change] does is potentially subvert the current road map. There is going to be less stability in transmission patterns, which means that current paradigms for elimination and eradication for most NTDs are no longer fit for purpose. There is a lot more uncertainty.” – Mark Booth, Climate and NTD researcher at Newcastle University. (Policy Perspectives)
There is an alarming overlap in where the impacts of climate change are likely to be most severe and those regions already disproportionately affected by neglected tropical diseases.The disparate impacts are felt most by populations living in low-income countries and those in disadvantaged communities of middle-income countries, especially in Africa and the Western Pacific region.
Climate change intensifies the difficulties of neglected tropical disease control by expanding vector habitats, disrupting water and sanitation systems, displacing populations, threatening food security, straining health infrastructure, and altering ecosystems and livelihoods. To meet these challenges, we must integrate climate resilience into neglected tropical disease control strategies and bolster the adaptability of health systems and communities.
Despite such tangible impacts from a warming planet, very little empirical research into direct impacts on neglected tropical diseases exists. It is clear that vectors like mosquito and sandfly populations are on the rise, but how their proliferation impacts the lives of communities at risk of neglected tropical diseases is still largely unknown.
The 2023 report of the Lancet Countdown on health and climate change recognized that “the multiple and simultaneous risks of climate change are amplifying global health inequities and threatening the very foundations of human health.”
While more research is needed, some interventions and strategies have shown promise in eliminating neglected tropical diseases within the context of a changing climate.
Combining traditional public health measures like mass drug administrations with climate-responsive strategies is crucial, highlighting the need for flexibility in response to evolving environmental conditions.
For example, integrated vector management, which incorporates climate data to mitigate changes in vector distribution, has proven effective in controlling diseases like malaria. This approach has also been pivotal in recent efforts to verify the elimination of river blindness in West Africa (Partner Perspectives).
Additionally, mobile health solutions, which have sped up the diagnosis of neglected tropical diseases, show potential for enhancing disease surveillance in climate-impacted areas. Research indicates that the effectiveness of mass treatment campaigns for diseases such as schistosomiasis, trachoma, and lymphatic filariasis is influenced by climate change, with factors like altered rainfall patterns affecting vector behavior and predictability, and drought periods.
By integrating climate resilience into neglected tropical disease control strategies and leveraging advancements in mobile health and community-driven interventions, the global health community can adapt to these growing threats. Collective efforts must focus on research, flexible public health measures, and resilient healthcare infrastructure to protect vulnerable communities.