Dr. Mahamadi Kientega from Institut de Recherche en Sciences de la Santé (IRSS) just published an important piece of work highlighting the emergence of insecticide resistance signs in Anopheles mosquitoes, in Burkina Faso. A former member Target Malaria’s Young Scientists’ Network, Dr. Kientega’s, recently featured on Malaria Journal and highlights the importance of monitoring mosquitoes’ resistance to insecticides in Africa. 

You recently published a scientific article in Malaria Journal. Tell us more about the publication. 

Between 2012 and 2017, me and my team members from Target Malaria collected of 1409 Anopheles gambiae sensu lato (s.l.). mosquitoes (978 females and 431 males) in three villages of Burkina Faso: Bana, Souroukoudinga and Pala. We sequenced the genome of these mosquitoes to study the evolution of variants associated with resistance to insecticides. 

The paper we published on Malaria Journal is named “Whole-genome sequencing of major malaria vectors reveals the evolution of new insecticide resistance variants in a longitudinal study in Burkina Faso. It is the outcome of a collective study between several scientific partners: the Institut de Recherche en Sciences de la Santé-IRSS (Institute of Research in Health Sciences) in Bobo-Dioulasso, MalariaGEN Vector Observatory and Target Malaria. The article examines the genetic evolution and resistance patterns of malaria vectors, particularly focusing on how these vectors adapt to insecticides over time in Burkina Faso. 

 What is the contribution of this study to malaria research? 

Our study makes a significant contribution by identifying genetic markers associated with emerging insecticide resistance. This knowledge is critical for malaria control programs, as it highlights the adaptive capabilities of malaria vectors, allowing for more strategic interventions. The findings suggest that current methods, such as the use of insecticide-treated nets (ITNs) and indoor residual spraying (IRS), need to be re-evaluated and possibly combined with new approaches to stay ahead of evolving resistance patterns. This research, therefore, aids in guiding policy and decision-making for malaria vector control efforts at regional and national levels. 

What is the next stage of your research, and what problem do you hope to solve with this project? 

Today more than ever, it is crucial to understand the genomics of mosquitoes to monitor and understand how this champion of biological evolution continues to evade vector control strategies. The next stage of our research will focus on deepening the conclusions of this study and explore new avenues of research to gain a better understanding of the wild mosquito population in Burkina Faso. My aim is to continue investigating genetic diversity, the population structure and the evolution of insecticide resistance variants in the An. gambiae s.l. populations in the western part of the country. I will put to good use the methods for sequencing and analysing malaria vector genomes I acquired during my fellowship at the Wellcome Sanger Institute in the UK. 

Follow Mahamadi on social media: 

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We had the pleasure of exhibiting at New Scientist Live for the first time last weekend! New Scientist Live is a major science exhibition in London on October 12-14, bringing in visitors from all over London. It was a huge opportunity for us to showcase our work to science-keen audiences of all ages. On Monday 14^th, it was schools’ day which allowed us to engage school children who had curious questions and stories about their own experience with mosquitoes. This was also the perfect age group to engage through our video and card games. 

_{Ignacio Tolosana and Lamin Jadama of the Discovery Team at Imperial College London showcasing mosquitoes to a visitor (Left). Video game demonstration for visitors (Right).}

Our stand featured our various communication tools, such as our card game “Mozzie Drive”, the   “Swarm” sonification, live mosquitoes and larvae allowing visitors to come face-to-face with mosquitoes.  Visitors could also play our new microinjection video game. It was created in collaboration with Michael Marston, a British video game developer, and Louise Marston, one of Target Malaria’s senior research technicians at Imperial College London.

The video game allows the player to enter a simulation laboratory, which has been modelled after our real laboratory, and play modules to experience various laboratory processes, such as microinjection. Microinjection is a key part of our research and science. It is a difficult process that necessitates skills and patience to sort out embryos and then inject them with a DNA solution. We have a blog which outlines the process written by Louise Marston, who is our top microinjector of mosquito embryos at the Discovery team in South Kensington. Read the blog here.    

_{Divine Dzokoto of Target Malaria Ghana looking at mosquitoes with a visitor. (Left) Visitors playing the card game. (Right)}

“It was a great opportunity for us to reach a new audience who were very supportive and amazed by our work!” – Divine Dzokoto 

We also showcased our new shirts featuring a design which aims to emulate a traditional African design. The artwork is inspired by the countries that we operate in, and that are primarily affected by the malaria endemic. We have two version, one in green and one in blue. Both versions of the design incorporate scientific illustrations to raise awareness on the lifecycle of the Anopheles mosquito, the contributions of Target Malaria but also other tools to fight malaria such as bednets, insecticide sprays and antimalarial drugs, as well as a figure representing our stakeholders and the women who have a hand in the fight against malaria.

Thank you to all the visitors who visited the exhibition and our stand! 

Malaria is a significant global public health challenge in Africa with the region carrying the burden over 90% of malaria cases and deaths. In the World Malaria Report 2023, Uganda is part of a group of five countries, including Ethiopia, Nigeria, Pakistan and Papua New Guinea, as collectively responsible for an increase in global malaria cases and deaths in 2022. Despite all the efforts to control the disease, WHO reported that there were an estimated of 12,7 million malaria cases and over 17,556 estimated deaths in Uganda. It also significantly strains our healthcare systems, as evidenced by the high rates of outpatient visits, hospital admissions, and deaths. 

This devastating impact of malaria in my country necessitates the need to design and deploy novel tools to supplement existing ones, whose effectiveness is being compromised by the emergence and spread of insecticide and drug resistance, changes in mosquito behaviour, and climate change.  

Target Malaria is working to develop genetically modified mosquitoes to complement existing vector control tools. Our objective is to develop gene drive mosquitoes to reduce the population of malaria mosquitoes and stop the transmission of the disease.  

The Uganda Virus Research Institute (UVRI), a department in the Ministry of Health, and constituent member institution of the Uganda National Health Research Organisation (UNHRO) is Target Malaria’s collaborating partner In Uganda. Since 2012, Target Malaria Uganda has been involved in characterizing mosquito populations in selected villages within Mukono and Kalangala districts to explore mosquito populations: species diversity, medical importance, seasonal population dynamics among others. Sustained stakeholder engagement has been taking place in these regions to consult local communities and to explain the purpose of the collections, the studies and the objectives of the project.  

This year in May, the UVRI team imported a strain of non gene drive genetically modified mosquitoes, called “male bias” strain. This is the same strain that was imported in 2022 in Burkina Faso. The male bias mosquitoes were imported from our partner institution, the Centers for Disease Control and Prevention (CDC) in the United States of America.  

Approval for this importation and contained use studies was obtained from the competent national regulatory authorities in Uganda, specifically the Uganda National Council for Science and Technology-UNCST (supported by technical review of the National Biosafety Committee-NBC) and the National Environment Management Authority-NEMA. Agreement was also obtained from the local communities around the UVRI campus. 

The studies on the male bias mosquitoes have been taking place these past months in UVRI’s Arthropod Containment Level 2 (ACL-2) insectary, the first of its kind in Uganda, inaugurated in 2019. The insectary was built and operates strictly following recognized international guidelines. It also meets national guidelines for biosafety.  

The insectary team is currently carrying out experiments on both local wild-type and genetically modified mosquitoes. UVRI researchers will conduct several studies on the male bias mosquitoes and will report the results to the regulatory authorities and stakeholders. The objectives of the studies are to confirm that the modification is working as intended, namely that it produces more male than female offspring; and collect information on the development and behaviour of the male bias mosquitoes. 

The male bias strain does not carry the gene drive technology. It is genetically modified to produce mainly male offspring (up to 95% under laboratory conditions). The male bias strain is not a vector control tool. The purpose of this phase is to understand this new fertile strain (compared to the sterile strain imported, studied and released in Burkina Faso), develop capacity, train Target Malaria teams at UVRI and engage with regulatory authorities and stakeholders in Uganda. 

Our current containment studies are part of our step-by-step development pathway taking us one step closer to finding long-lasting solutions to fighting malaria in Africa. Our objective in the near future is to develop gene drive mosquitoes that could be used as a vector control tool to supplement existing interventions. 

When most  people hear about research into mosquitoes, they see it as fascinating. Today, I wish to delve into an innovative study by Target Malaria Ghana, which aims to shed light on one of Africa’s most pressing public health issues—malaria transmission. If you have been wondering how scientists unravel the secrets of these tiny, yet mighty creatures, your question is about to be answered. 

The mesocosm magic 

Target Malaria Ghana is conducting a mesocosm study at its laboratories, The Mosquito Ecology Facility, based in the Department of Animal Biology and Conservation, at the University of Ghana, Legon. A mesocosm study can be likened to a world where scientists create a miniature ecosystem an outdoor space that simulates the natural environment of mosquitoes. This is precisely the case where researchers control and observe mosquito populations under various conditions without the unpredictability of a natural setting or the rigidity of a lab. 

_{A mesocosm setup} 

Why mosquitoes? 

In Ghana and many parts of the world, mosquitoes are more than just a nuisance – they are vectors of diseases like zika, west nile, chikungunya, dengue, and malaria. Together, mosquito-borne diseases claim over 700,000 lives every year around the world. Malaria alone kills over 600,000 mostly in Africa ( World Malaria Report 2023). Target Malaria Ghana is particularly interested in studying the Anopheles gambiae type, a primary culprit in malaria transmission in West Africa. 

The study at a glance 

In this mesocosm study, the scientists in the Mosquito Ecology Facility, are investigating how the population of Anopheles gambiae is regulated through measured actions like density manipulation, daily monitoring, and the observation of their transition to adulthood. To manipulate the density, the scientists vary the number of larvae in their mesocosm setups (from as few as 25 to as many as 400), this way, they can observe how different population densities affect the mosquitoes’ survival and development.  Every day, they watch larval and pupal mortality rates, the time it takes for the larvae to develop, and the percentage of mosquitoes that do not survive to the pupation stage. 

_{Image of an Anopheles gambiae pupa} 

After the larvae become pupae and then adult mosquitoes, they are moved into the laboratory. Here, scientists study their emergence rates, size, and mortality to understand the long-term effects of their early life conditions. 

As the mosquito population increases, competition for resources like food and space begins. This competition can influence their growth, survival, and overall health. By understanding these dynamics, Target Malaria Ghana hopes to develop effective protocols for mosquito rearing and, their control.  

_{The life cycle of a mosquito} 

The broader vision 

This study is not just an isolated scientific experiment, it is part of a larger scheme. Target Malaria Ghana is working towards developing protocols for rearing genetically modified mosquitoes. While Target Malaria Ghana does not study genetically modified mosquitoes, the objective of the mesocosm studies is to ensure that the genetically modified mosquitoes are introduced into the wild efficiently and sustainably.  

In the fight against malaria, every piece of information counts. The mesocosm study by Target Malaria Ghana offers crucial insights into the life cycle of one of the world’s deadliest pests, the one that kills the greatest number of people in the world, mostly in Africa. By learning more about how mosquitoes live, grow, and die, scientists get a step closer to a world where malaria is a thing of the past. 

For World Mosquito Day 2023, we shared a video answering the question Is it possible to dissect a mosquito? To answer the question simply: yes, it is possible to dissect a mosquito, but very carefully. 

Mosquitoes are dissected to learn more about their anatomy and function. Two organs that are important for their studies are the spermatheca (where the sperm is stored after mating) and the midgut.  

_{Female mosquito anesthetised. CDC Foundation (from video)} 

To better picture the anatomy, we recorded a live footage of a dissection. In the video, show a female mosquito that has been anesthetised. To remove the spermatheca, which can be seen through a dissecting scope, the mosquito body is anchored with one pair of fine forceps, using another pair of forceps to gently pull on the last segment of the body to tear it from the body. Internal organs remain attached to this last segment. 

Among the first to be released is the spermatheca. The spermatheca is a round black disc that stores sperm transferred from the males to the females during mating.

_{Spermatheca. CDC Foundation (from video)} 

On the right we can see a spermatheca from a mated female. The black arrow is pointing at the sperm in the opened spermatheca compared to the one on the left from an unmated female that does not contain sperm.  

If you continue pulling on the last segment of the body, the midgut will become visible. The midgut is an essential organ responsible for digesting the blood after the female mosquito has fed. If a mosquito was infected with malaria parasites when consuming their blood meal, the parasites will form oocysts in the gut wall. The midgut can be stained 6 to 8 days after the feeding to check for malaria infection, and the oocysts will look like round dots. 

_{Midgut wall. CDC Foundation (from video)}

For example, the midgut on the left is from an uninfected mosquito with no malaria parasites.  

On the right, black arrows are pointing at some of the oocysts, indicating the mosquito was infected with the malaria parasite.  

To find out more about Target Malaria’s work at the CDC Foundation, please visit here. 

I am excited to join the team at the Imperial South Kensington campus as a Research Technician, driven by my passion for malaria research and exploring new tools to combat the disease. I hold a BSc in Public and Environmental Health from the University of The Gambia, and I bring over six years of experience in malaria transmission blocking experiments, mosquito culturing, field mosquito collection, and other molecular work. 

My career as an entomologist began 6 years ago through an internship at the Medical Research Council (MRC) The Gambia unit at the London School of Hygiene & Tropical Medicine (LSHTM), working on a project aimed at using Anopheles gambiae s.l. swarm trapping as a complementary tool against residual malaria transmission in eastern Gambia. This experience set a high standard for me and inspired me to strive for excellence in the field of medical entomology. In 2018, I was hired as a Trainee Scientific Officer with the Vector and Molecular Biology team at MRC The Gambia unit at LSHTM, and a year later, I was promoted to Scientific Officer. 

I am now eager to expand my knowledge in malaria control research by exploring gene drive technology as a new tool to suppress wild mosquito populations and reduce malaria transmission. I look forward to this next phase of my journey with the innovative Discovery Team. 

The high-pitched buzzing of a mosquito typically brings to mind memories of itchy bites and thoughts of the deadly disease malaria, and other viral infections like dengue, zika, and chikungunya. While these associations are well-known, it is lesser known that mosquitoes, may be occasional plant feeders.

Both male and female mosquitoes from various species feed on plant fluids, and some even contribute to pollination. The Culex and Aedes mosquito species have been documented feeding on floral nectar and aiding in plant pollination, but there was no scientific evidence suggesting that Anopheles gambiae played a role in pollination. Further scientific investigation needed to be undertaken.

Investigating Mosquitoes in the Wild

To explore this potential, I conducted an extensive study in two malaria-endemic villages in Ghana. Over 608 hours were spent searching for interactions between Anopheles gambiae and flowers. The result of this observation demonstrated that no such interactions were observed. Not a single Anopheles gambiae was seen on any flowers. In contrast, a few Culex species were found on petals and leaves.

         _{Culex mosquito species spotted on various plant parts in the wild.}

To further investigate this, 709 Anopheles gambiae mosquitoes were collected – 246 from indoor environments and 463 from outdoor locations such as under leaves, in abandoned houses, and among packed blocks. These mosquitoes were examined under a light microscope for pollen grains, but none were found.

Controlled Experiments: Testing for Pollination Potential

To determine if Anopheles gambiae could pick up pollen in a controlled environment, 120 newly emerged, unfed Anopheles gambiae mosquitoes were introduced to the flowers of 11 different plant species in cages. The mosquitoes visited all the flowers provided to them overnight.

_{An. gambiae visiting flowers in the laboratory}

Upon examination the following morning, some mosquitoes were found with pollen grains, mostly attached to  the head region (antennae and mouthparts), abdomen, and legs.

_{Pollen attached to An. gambiae under light microscope (x100).}

Energy Sources and Flower Visitation

The next experiment was to try to understand how Anopheles gambiae obtains energy if not frequently visiting flowers. The mosquitoes were introduced to branches of the same 11 plant species, and their visits to various plant parts were recorded.

_{Plant branches with inflorescence in a cage to which An. gambiae were introduced}

The results showed that most of the mosquitoes preferred visiting leaves (90 visits) and nodes (54 visits) over flowers (just 10 visits).

This behaviour suggests that Anopheles gambiae likely may be deriving its energy from other parts of the plant more often than from flowers. Since the effectiveness of a pollinator is largely determined by its frequency of flower visitation, it can be concluded that Anopheles gambiae may not be an effective pollinator.

Conclusion

While Anopheles gambiae mosquitoes are capable of picking up pollen in a controlled environment, their infrequent visits to flowers in the wild indicate they are unlikely to play a significant role in pollination. Their primary source of energy seems to be derived from leaves and other plant parts.

The National Biosafety Agency of Burkina Faso published on August 30, 2024 a press release about the biosafety measures taken in the implementation of the Target Malaria in Burkina Faso at the Institut de Recherche en Sciences de la Santé in Bobo-Dioulasso.

This release calls on the Burkina Faso public to trust the decisions made my Burkinabè regulatory agencies authorising research on genetically modified mosquitoes as part of the  Target Malaria  project.

“ANB, in this statement, wishes to reassure national and international public opinion that all biosafety measures have been taken to ensure the safe use of these GMOs both in a contained environment (in the laboratory) and in an open environment (in the environment), for each stage of the project’s development. It also invites the public to have confidence in the state structures and authorities set up to coordinate, develop, monitor and use research for the benefit of our well-being and the development of our country, and to distance themselves from scientific untruths, in particular the conflation of Anopheles mosquitoes, the vectors of malaria (the subject of the Target Malaria project), and Aedes mosquitoes, the vectors of dengue fever”.

Full release (in French): https://www.infosciencesculture.com/en/node/219

Target Malaria supports and scrupulously respects stringent, competent, responsible and transparent regulations to advance research into the use of genetically modified mosquitoes to combat malaria in Burkina Faso and Africa.

This statement reinforces the strong declaration made by the National Academy of Sciences, Arts and Letters in August 2024.

For the past 6 months, I have worked on the Global Communications team at Target Malaria. This has been an opportunity to thoroughly explore the world of science communications and approach the task of simplifying complex scientific concepts for a range of audiences.  

I have had the opportunity to work on numerous campaigns commemorating World Malaria Day and World Mosquito Day, and even got to plan and lead a campaign of my own for Africa Day. I have approached communications from all angles, doing everything from creating illustrations and designing content for campaigns to researching awards to celebrate our hardworking researchers and stakeholder engagement teams. 

Much of my work has been dedicated to the upkeep of the Target Malaria website, from performing admin tasks to writing blogs on events and scientific developments across our country teams; I broke down dense political documents and shared  fun creative concepts for campaigns. 

A mosquito animation created for World Mosquito Day. 

I also enjoyed engaging the public at the Great Exhibition Road festival: playtesting the Microinjection video game, showcasing live mosquitoes in their different life stages (which I later created animated GIFs of) and showcasing the Mozzie Drive card game. 

It has been amazing to witness this year’s major highlights in the entire Target Malaria team, from hosting the President of the National Academy of Sciences, Arts and Letters in Burkina Faso, to gracing the stage of the annual TED conference. 

It has also been a pleasure to work with the Global Communications team and I would like to thank Morgane Danielou for being a gracious and uplifting leader, Yann-Pablo Corminboeuf for helping me flourish creatively and explore new approaches to digital art, and Lorraine Gibson for being a constant guiding presence throughout the internship. During my term we also welcomed Ndeye Mane Sall to our team, and I would like to thank her for her genuine consideration of the whole team’s input and for always being there to lend a helping hand. Finally, as the newest intern, Zainab Shire has brought such a bright energy and fresh ideas to the table and as a fellow recent graduate, I wish her the best of luck as she carves out a career path. 

It has been a pleasure to be a part of this team, and I am looking forward to seeing what the future holds as I go forward.