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Climate change is amplifying mosquito-borne disease outbreaks

Learn how entomologist Ruth Müller and her team work to prevent and control this global threat

Dr Ruth Müller is a biologist and Professor of Entomology at the Institute of Tropical Medicine in Antwerp. She talked to Samik Kharel about her research which aims to better understand the relationship between climate change and mosquito-borne disease risks to humans.

DSC06832_crop2 Prof Dr Ruth Müller

Can you explain how mosquito-borne diseases are affected by climate change? What innovative approaches are you bringing to address them? 

When we talk about climate change, it is not just about the temperature increase, but also about changing precipitation patterns and drought, which all directly influence our social behaviour and the population dynamics of mosquitoes. My research focuses on understanding these dynamics and our options to prevent and control mosquito-borne disease outbreaks. For vector control, it is important to use multiple methodologies. Different geographic regions host a variety of vector species with different ecologies, and we need to understand their behaviour before taking action. For example, the primary dengue vector species, Aedes aegypti, is less well-adapted to colder ecoregions than the vector species Aedes albopictus (the Asian tiger mosquito), with a lesser ability to transmit the dengue arbovirus. There are many innovative biological and genetic vector control tools which we test for their suitability in a different contexts. We prioritise interventions which involve local communities as they can significantly contribute to preventive measures and co-develop new solutions. The exploration of the traditional vector control methods in various parts of the world has been also our priority.

Nov_07_Rasipauwa (56)crop Preparing traps to collect mosquito eggs in Nepal

Can you share some examples of your research in Nepal which were exploring the impacts of climate change? 

A few years ago, prior to the Covid-19 pandemic and recent dengue outbreaks, we conducted an eco-bio-social study in collaboration with the Ministry of Health and Population. The study aimed to explore perceptions of climate change across various ecoregions of the country. By comparing meteorological data on climatic changes with people's perceptions—such as the observed temperature increase in summers and milder winters over the past few years—we demonstrated that individuals accurately perceive climatic changes. They were also well aware of the indirect effects of these changes on their lives over the years, such as the emergence of new vector species or increased abundance of mosquitoes during post-monsoon season. The recent natural disasters and disease outbreaks in the Himalaya Hindukush region and Nepal makes parts of the country inaccessible, so there have been several challenges to our much-needed follow-up study.  

DSC06001_crop Car tyre collection in Nepal is common for recycling purposes - tyres are a favourite habitat for dengue vectors

With growing outbreaks of vector-borne diseases in the country, what are your perspectives on mobilising public awareness and on actions needed to address these challenges? 

First of all, the government needs to disseminate basic information about vector-borne diseases and their prevention and control. We have set up a mosquito disease information centre at the National History Museum of the Tribhuvan University, which helps to educate people on mosquito-borne diseases. We also believe in a bottom-up approach, where the community informs the experts about the presence of invasive mosquitoes and co-develops preventive measures for vector-borne diseases. For example, in Belgium, citizens have been helping us tremendously by taking pictures and informing the national public health authority about the presence of exotic mosquitos. We are going to use a similar citizen science approach in Nepal, where many villages and towns are hard-to-reach, especially in the high mountainous regions. Such a web-based, citizen science project could be feasible since  almost everyone is using a mobile phone nowadays. The knowledge from active and passive mosquito monitoring will allow us to closely follow-up the spread of mosquitoes and associated vector-borne diseases and hopefully induce a faster response to these climate-related health threats.

I am proud to say that our research on the spread of dengue vectors towards colder ecoregions in Nepal is truly spearheading. Typically, major research on global warming is limited to countries in the North, while only few countries in the Global South put this type of research on their priority agenda. I believe that the voice of the Global South needs to be louder to create a critical mass of policymakers asking for solutions and making “health in the face of climate crisis” a high priority. The global community could strongly benefit from a collaborative South-North effort to study the impacts of climate crisis on health.

Nov_09_Dunche (33)_crop Nepali and ITM entomologists

As the co-chair of the scientific committee for the 2023 ITM Colloquium, jointly organised by ITM and the Nepal Health Research Council in Kathmandu, could you elaborate on the importance of this event?

It is an honour to organise such an important event, which will amalgamates climate science, environmental health and human health and stimulate a much needed interdisciplinary and multisectoral discussion. Our aim is to bring internationally renowned scientists from different health disciplines and sectors together to share expertise and knowledge from all over the world and establish a joint force to tackle diseases burdened by the climate crisis.

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