My Climate Risk Interdisciplinary Learning Group
11 December 2023; 13:00 – 14:00 GMT
Presenter: Richard Selby
Dr Richard Selby is a parasitologist who has worked on Neglected Tropical Diseases since the mid-2000s. In 2022, Richard joined the NGO Sightsavers as the Head of Portfolio for NTD Research, leading a team of eight African researchers.
Our research centres on improving control of five core diseases (schistosomiasis, soil transmitted helminths, onchocerciasis, lymphatic filariasis and trachoma). Conducting research that addresses current problems faced by Sightsavers’ supported control efforts and anticipates future adaptions needed in our changing environment.
Our portfolio has active research underway in eleven nations including a collaboration with Walker Institute working to predict epidemiologic changes bought by likely climate scenarios.
Paper to be presented
Title: Climate Change and the Neglected Tropical Diseases
Author: Mark Booth
Link to paper: Climate Change and the Neglected Tropical Diseases
On the 11th December Dr Richard Selby, an expert parasitologist, gave the final MCRIRG presentation of 2023. This was an opportunity for all My Climate Risk researchers across a variety of specialisms to consider the interaction between climate change and neglected tropical diseases (NTDs), via the work of Mark Booth.
Dr Selby’s talk encompassed a review into the cross-cutting issues likely to affect the transmission of NTDs in the future, including key information on the most vulnerable stages of the disease cycles and also the current state of research into how future climate change is likely to affect both disease severity and spread. In his role as Head of Portfolio for NTD Research at Sightsavers, a leading NGO which has provided 1.6 billion treatments since it was founded in 1950, Dr Selby leads a team of African researchers at the cutting edge of this work. He explained that the three pillars of Sightsavers involve working across Africa and in some parts of Asia to fight five specific NTDs (Lymphatic Filariasis, Onchocerciasis, Trachoma, Schistosomiasis and Soil Transmitted Helminthiasis), protect sight and promote disability rights. Given Dr Selby’s previous experience researching Human African Trypanosomiasis, he also included this disease in his summary.
We were introduced to the key parasites, vectors and hosts of each of the diseases and how weak points in their lifecycles can be exploited in trying to eradicate the NTDs. For example Water, Sanitation and Hygiene (WASH) improvements can reduce instances of open defecation and improve hygiene standards, thus reducing the spread of Trachoma, Soil Transmitted Helminthiasis and Schistosomiasis. However, despite the apparent simplicity of this approach, as climate change lowers water tables and reduces access to water, diseases that had been eradicated in some areas, may begin to return. Equally, some of the other results of climate impacts, such as population movement and manmade adaptation projects can result in unexpected spreading of disease and proliferation of vectors as they exploit habitats provided by the need to store more water. Climate change can also alter human-animal interactions, causing people and their agricultural and aquaculture projects to encroach on the habitat of some of the disease vectors. Soil, water and air are all critical during phases of parasite and bacteria lifecycles and so a warmer, potentially drier climate will affect where and when these diseases are likely to appear, with some areas becoming less suitable at certain times of year, but others suddenly having to face NTDs for the first time. A key part of these changes could be the way that host behaviour is disrupted by changes to the climate that could cause asynchronicity between hosts and vectors, either increasing or decreasing disease prevalence. Sightsavers need to model how and where NTDs will spread in order to find ways to eliminate them that will remain sustainable in the future.
In the discussion which followed Dr Selby’s presentation, it was suggested that perhaps in trying to harvest water in case of shortages due to climate change, we are providing new habitats for vectors and encouraging their proliferation. Dr Selby was able to explain that whilst yes, this can be a difficult area, with black flies finding that concrete dams are a perfect habitat, there are barriers that can be put in place to reduce the likelihood of vectors settling. The key in cities is surveillance, for example in Liberia, Lymphatic Filaria was found in a suburb where none of the mosquitoes that spread the disease were present. It is important to work out how this happens, as in some cases one species of fly has been known to fill an environmental niche that another cannot.
The importance of community engagement was also discussed and how, for action to reduce the threat of NTDs, decision making needs to be community driven. Top-down projects may be cheaper to deliver at standardised quality and scale, but inclusion of bottom-up approaches allows solutions from the ground, which tend to be more successful in the long term. This led to a question about how we can engage local stakeholders in responding to early warnings, where these are in place. From experience in the field, Dr Selby was able to reflect on how fragility at a local level can be addressed by encouraging local communities to take part in research on NTDs. For example, in the case of Schistosomiasis, asking local stakeholders to capture snails so that researchers can examine them to see if they are infected, not only engages people in a practical way, but also spreads awareness of the dangers of NTDs and how these could be avoided. It was mentioned that one barrier to locally led adaptation is the lack of access to digital reporting systems. Where these are in place, Citizen Science projects have been shown to produce results that are just as robust as expert information and over a larger scale, but even though mobile phones are becoming more prevalent across rural Africa, unreliable communications networks are sometimes holding such initiatives back.
Socio-economic factors were again shown to be very important in the vulnerability of populations to diseases, including those engendered by a lack of WASH, ill health due to poor nutrition, insufficient healthcare resources or understanding of risks posed by NTDs. In working to map how climate change may affect NTD risk, these factors will need to be taken into account. NTDs are a huge part of many sustainable development goals and their massive economic burden has already been realised, but now the effect of climate change will also need to be factored in to any eradication campaigns.
Dr Selby’s presentation was an excellent introduction to NTDs and their devastating effects. However, we were also left feeling hopeful that there are ways to combat these diseases and that the scientific community will be pivotal in plotting the projected effects of climate change on parasite prevalence, whilst also engaging local stakeholders to ensure projects are best fitted to their needs.