Time to innovate:
Malaria in a changing world

I come from Madagascar, a country with a high morbidity and mortality in terms of tropical and infectious diseases, particularly malaria. As a medical doctor, I saw first-hand the ravages of these diseases on people’s lives. Although my role as clinician was important, it was limited, and I wanted to move to a field that may have larger impact. 

My PhD project focuses on the evaluation of a novel digital diagnostic test for the detection of malaria parasite infections in Africa. The test has high sensitivity, so can detect asymptomatic infections and low levels of parasites, which are often missed by conventional diagnostics. 

To achieve the goal of malaria elimination, it is important to detect and treat these infections because they constitute a substantial malaria reservoir that helps maintain malaria transmission. The test could also be used as a point-of-care test, with a time to result of less than 30 minutes, making it suitable for the African context where access to a laboratory is often difficult. 

Climate change and land use changes represent great threats for malaria control, and the African continent is especially vulnerable to these changes. It is crucial to closely monitor the trends in terms of infections and deaths attributable to malaria with a robust and timely surveillance system. For this system to be effective, having an accurate and easily deployable diagnostic tool able to detect all malaria infections is required. 

Before its deployment at large scale, however, we need to understand if the test performs accurately and efficiently in real field conditions. This represents the focus of my PhD project. 

I think the youth, and especially the African youth, have a fundamental role in the fight against malaria, including in research. I was very lucky to have been selected to do my PhD thesis with the Digital Diagnostic for Africa research group, but there are many young people in Africa very motivated and with new ideas just waiting to be encouraged and supported. 

I spent many years of my upbringing in countries that are affected by malaria and other vector-borne diseases. Working on malaria is particularly important to me, because it’s a disease that predominantly kills very young and poor children in sub-Saharan Africa, who should have the right to a healthy childhood.  

I chose to pursue a PhD in genetic engineering because I found the science fascinating and, on a more practical level, I truly believe it can bring about an important contribution to the fight against malaria. My research centres around developing self-limiting genetic strategies to suppress populations of the main malaria mosquito in Africa, Anopheles gambiae. In practice, this means genetically modifying this mosquito species to create versions of it that, if released, could reduce wild populations of this disease vector. 

Importantly, the effects of this reduction are temporally and geographically localised. The hope is that these or other self-limiting strategies could be released, both as population-reduction tools, and to strengthen the regulatory pathway for the potential release of the more powerful gene drive mosquitoes. 

The changing world is affecting malaria in several ways, from climate change that threatens to widen the geographical scope of this disease, to the emergence of pandemics that hamper malaria programs, to migration of vector species in regions where they are not native to. On the other hand, the changing world also means more research on new tools, socioeconomic development and better health systems, so there are also good reasons for being cautiously optimistic.   

The intervention I work on is called seasonal malaria chemoprevention, which aims to prevent disease in young children specifically. In areas with high levels of malaria transmission, which is very seasonal, community health workers go house to house once a month to deliver preventive medication to children at high risk of severe disease. However, there is established resistance to the medicines we use for seasonal malaria chemoprevention in most of East and Southern Africa. My work revolves around using a variety of approaches to estimate the effectiveness of seasonal malaria chemoprevention in places where resistance is already high.   

The malaria parasite is highly adaptive and has developed resistance to every treatment used, as well as diagnostic tools. My work is predominantly orientated around understanding the impact of resistance on malaria chemoprevention, how environmental factors affect seasonality and how to combine this to most effectively use our current tools to save lives in a changing landscape.   

My background is in mathematics, and I always really enjoyed mathematical biology, but had only done a tiny bit of mathematical epidemiology before I applied for my PhD at Imperial, totally on a whim.

My advice to other young scientists is to invest in your network, especially with researchers living and working in countries affected by your field of research. These conversations and relationships have been one of the most rewarding parts of my work and being able to align my research with public health priorities allows my work to have the most impact. But most of all, don’t lose hope. Sometimes tackling malaria burden can feel insurmountable, but remembering that even small gains have the potential to save lives keeps me motivated.

My hope is that we are able to reverse the trends we have seen in current years of the malaria burden increasing year on year and starting to see decreases again in cases and deaths globally.   

I am part of an interdisciplinary team that develops mechanistic models to predict malaria transmission given different intervention strategies.  

My specific project involves what it takes for an individual mosquito to transmit malaria. One important factor is that infected mosquitos must survive while the parasite matures (the extrinsic incubation period, EIP). However, while the parasites need 10 days to reach maturity, the average adult mosquito lifespan is typically less than 10 days. We think that a small number of long-living mosquitoes are responsible for a disproportionate amount of transmission.  

During my PhD, we developed a mathematical model of parasite development within the mosquito to characterise variability in EIP. We then investigated how incorporating these new EIP estimates into a malaria transmission model affected the ability of the model to predict long-term changes in malaria transmission in a high-transmission region of Senegal. 

One of the many reasons insecticide-treated bed nets (ITNs) have been so important for reducing malaria is because the insecticide can reduce the average mosquito life expectancy even if they do not completely block biting. However, resistance to the class of insecticides used on nets is spreading, so we have been modelling the short-term public health impact of distributing nets treated with a new insecticide. 

I strongly believe social justice and public health are integral to reducing the burden of malaria. Inequality in the geographic distribution of malaria is extremely high, and within endemic countries malaria disproportionately affects people who are most economically marginalised. 

There is, however, hope: since 2015, nine countries have been certified by the World Health Organization (WHO) as malaria-free, and with continued funding, political will and a reduction in global inequality more countries will be able to reach elimination. 

Health inequalities across the world is something I have always sought to proactively remedy. The complexity of malaria as a disease, its global burden, as well as the impact that global issues and politics can have on it make it a fascinating and challenging field of study. 

Malaria is a complex disease at the intersection of human social patterns, demography, economics, and environmental factors – and any change in these patterns may affect disease transmission and our strategies to combat it. 

Since the 1950s, insecticides have been one of the most effective tools in driving down the spread of malaria. Resistance to these insecticides has steadily been emerging ever since in malaria mosquitoes, and we now see many high-transmission malaria areas with very complex and intense resistance patterns. 

Adding extreme environmental variations caused by climate change to this will likely impact current transmission patterns and highlights the need for new adaptable tools to control malaria. My work focuses on characterising these different resistance patterns and tries to understand how these changes may impact malaria transmission, so we can adapt our control strategies in a timely manner. 

Over the next 10 years, I’m hoping to see a range of new tools to prevent and control malaria, including new insecticides, vaccines, and gene-drive technologies. This would have to be combined with greater community engagement and empowerment in malaria-affected areas, as well as improved access to diagnosis and treatment. 

I also hope for more political commitment and funding for malaria control and elimination, both domestically and internationally. New partnerships and collaborations, particularly between malaria-affected areas, will hopefully also be something we see more of in the next decade.