As climate change reshapes vector ecology and human mobility fuels global connectivity, understanding the transboundary risk of mosquito-borne diseases becomes increasingly urgent. A recent modelling study published in The Lancet Planetary Health by Poongavanan et al. highlights how Africa, a continent with large areas of vector suitability but limited surveillance capacity, is at substantial risk of dengue virus (DENV) introductions.

Despite the presence of competent vectors (Aedes aegypti and Aedes albopictus) and favorable environmental conditions, dengue remains underreported in Africa due to diagnostic gaps and clinical overlap with diseases like malaria and yellow fever. The study aims to identify African airports and regions at the highest risk of receiving viraemic travelers from dengue-endemic countries, integrating air travel data with climate-based transmission suitability.

To estimate the risk of dengue virus introduction into Africa, the authors combined high-resolution climate, demographic, and mobility datasets into a novel modelling framework. They focused on 2019 as a reference year, collecting air travel data from the International Air Transport Association that tracked passenger flows from 14 dengue-endemic countries in Asia and Latin America and 18 African countries that had reported outbreaks over the past decade. This dataset covered 197 commercial airports across the continent. To address the limitations of sparse and often unreliable case data, they used a climate-based “P index” to estimate transmission suitability—essentially the reproductive potential of an infected mosquito under local environmental conditions. They then enhanced this metric by integrating population density, creating a composite index that reflects both ecological and demographic drivers of local transmission potential.

Using these data, the team developed a “risk flow metric” that calculates the probability of dengue importation into each African airport by combining travel volume, transmission suitability at the point of origin, and temporal alignment with local conditions conducive to dengue spread. This approach allowed them not only to rank countries and cities by relative importation risk but also to assess whether these risks were likely to coincide with seasonal windows of heightened local transmission suitability.

Key Findings

Their results revealed that countries in eastern and southern Africa—such as Kenya, Uganda, Mauritius, Egypt, and South Africa—were most exposed to dengue introductions from Asia, driven largely by travel volume and temporal synchrony with local climatic conditions. In contrast, countries in western Africa, including Senegal and Côte d’Ivoire, faced a greater risk of introductions from within the continent itself, suggesting strong regional transmission dynamics. Interestingly, some of the countries with the highest estimated introduction risk, such as South Africa, had relatively low local transmission suitability, implying a low likelihood of outbreak despite frequent viral introductions. On the other hand, countries like Mauritius and Egypt exhibited both high introduction risk and seasonal windows of high suitability, marking them as potential hotspots for outbreak emergence.

Another key insight from the study was the importance of intra-African connectivity. Patterns of regional travel were found to contribute significantly to dengue risk in both western and eastern Africa, highlighting the need for improved surveillance and early detection efforts not only at international borders but also within the continent. Furthermore, the study emphasized the potential impact of climate change on dengue suitability in areas that are currently considered low-risk, such as the Ethiopian highlands, which may become more vulnerable as temperatures rise.

By combining travel data with climate and population metrics, this modelling approach offers a powerful, data-driven tool to guide dengue preparedness strategies in Africa and beyond, exemplifying how modelling approaches integrating climate, demography, and mobility data can enhance early warning systems. However, the authors also caution that several limitations must be considered. The analysis is based on relative risk estimates derived from ecological and statistical models, rather than direct counts of imported cases. Moreover, due to the lack of comprehensive genomic data and traveller screening records, the model’s predictions have yet to be empirically validated. In regions with more robust surveillance systems, travel histories of infected individuals could help refine such models, and the ongoing expansion of dengue virus genome sequencing may soon enable high-resolution reconstructions of transmission chains.

Additionally, the climate-based “P index” used to estimate transmission suitability does not incorporate vector abundance, mosquito control measures, or behavioral factors, all of which can modulate real-world transmission risk. The reliance on air travel data also underrepresents land-based and informal travel routes—especially between neighbouring countries—which are harder to quantify but may significantly contribute to viral spread. Finally, trade-related pathways, such as the movement of mosquitoes in goods like used tyres, remain outside the scope of this framework. Despite these constraints, the model represents a major step forward in forecasting dengue introduction risk and offers a scalable, adaptable approach for guiding future surveillance strategies—particularly in light of expanding dengue suitability zones under climate change.

Read the full open access here: https://doi.org/10.1016/S2542-5196(24)00272-9

Poongavanan, J., Lourenço, J., Tsui, J. L.-H., Colizza, V., Ramphal, Y., Baxter, C., Kraemer, M. U. G., Dunaiski, M., de Oliveira, T., & Tegally, H. 2024. Dengue virus importation risks in Africa: a modelling study. The Lancet Planetary Health, 8(12), E1043–E1054. 10.1016/S2542-5196(24)00272-9 External Link

As arbovirus outbreaks continue to surge globally, a new study sheds light on the overlapping environmental risks for dengue, Zika, chikungunya, and yellow fever—all transmitted primarily by Aedes aegypti and Aedes albopictus mosquitoes. Among the contributing authors is Moritz Kramer, a researcher at the University of Oxford and a key member of the E4Warning project. The study is a result of international collaboration between leading institutions, including Oxford, the London School of Hygiene & Tropical Medicine, the University of Melbourne, the Boston Children’s Hospital, University of Washington University of Cambridge, Nagasaki University, niversity of Florida, the World Health Organization, and the Harvard Medical School.

 In this large-scale study, researchers compiled over 21,000 occurrence records and developed the most comprehensive global environmental suitability maps to date, using a joint ecological niche modelling approach. What makes this work stand out is its integration of multiple diseases, correcting for long-standing biases in surveillance data, and providing a common suitability framework for all four diseases.

 Key findings include:

• An estimated 5.66 billion people live in areas suitable for dengue, Zika, and chikungunya—around 73% of the global population.

• 1.54 billion people live in areas suitable for yellow fever transmission.

• The study reveals high overlap in suitable areas for dengue, Zika, and chikungunya, indicating that any region reporting one of these diseases could be at risk of the others.

• Risk maps show new potential hotspots in areas like West and Central Africa, southern Europe, and parts of Asia, where surveillance is low or diseases are underreported.

• Models highlight that underreporting and limited diagnostic capacity in low-income countries may skew perceived disease distribution, underlining the importance of adjusting for surveillance capability in global risk mapping.

By using a two-stage modelling strategy—one for disease risk and one for surveillance capacity—the researchers produce more accurate and actionable risk assessments, offering a better foundation for targeted disease surveillance, early warning, and response systems.  The results emphasize the need for integrated arbovirus monitoring and the value of cross-disease models in a world of expanding ecological and climate pressures.

Read the full open access here: https://doi.org/10.1038/s41467-025-58609-5

Lim, A., Shearer, F. M., Sewalk, K., Pigott, D. M., Clarke, J., Ghouse, A., Judge, C., Kang, H., Messina, J. P., Kraemer, M. U. G., Gaythorpe, K. A. M., de Souza, W. M., Nsoesie, E. O., Celone, M., Faria, N., Ryan, S. J., Rabe, I. B., Rojas, D. P., Hay, S. I., Brownstein, J. S., Golding, N., & Brady, O. J. 2025. The overlapping global distribution of dengue, chikungunya, Zika and yellow fever. Nature Communications, 16, 3418. https://doi.org/10.1038/s41467-025-58609-5

And in the E4Warning Zenodo repository: https://zenodo.org/records/15223772

As members of the E4Warning consortium, Gina Tsarouchi, Quillon Harpham (HR Wallingford), Lyra Tyson (UPF), and Remy Hoek Spaans (BSC) traveled to Sri Lanka in November to participate in a workshop organized by Dr. Lahiru Kodithuwakku and Gina Tsarouchi. The event, in collaboration with the National Dengue Control Unit (NDCU) and the Ministry of Health, focused on enhancing innovative tools for dengue prediction and control.

The workshop aimed to train participants in using the D-MOSS platform, a live dengue forecasting system combining satellite earth observation data, climate models, and statistical tools to provide probabilistic forecasts of dengue outbreaks. It also served as a valuable opportunity to adapt the methods to Sri Lanka’s unique public health context, informed by input from local professionals.

Bringing Together Experts from Across Sri Lanka

The workshop attracted over 80 participants from districts across the country, including entomologists, regional epidemiologists, medical officers of health, academics, NGOs, and representatives from the NDCU. This diverse group ensured that the discussions were enriched with practical insights and multidisciplinary expertise.

Dr. Preshila Samaraweera kicked off the workshop with an informative presentation on Sri Lanka’s progress in dengue control, highlighting current research projects and interventions. This set the stage for the D-MOSS training sessions, where participants had hands-on opportunities to test the system and provide feedback.

Training, Feedback, and Collaboration

The D-MOSS platform was well-received, with participants exploring its ability to visualize past, current, and forecasted dengue trends. One participant noted:

“These elements collectively offer a comprehensive view of past, present, and predicted dengue trends, supporting proactive planning and response.”

Following a lunch break, attendees learned about the statistical modeling methods used in E4Warning, with a focus on interpreting probabilistic forecasts. A group discussion then explored ways to enhance the dengue early warning system, including the integration of new data sources such as mobility patterns and socio-economic data. The day concluded with a presentation on the Mosquito Alert platform, sparking a lively conversation about how citizen science could contribute to vector control in Sri Lanka.

Lessons Learned and Next Steps

Reflecting on two intensive days of learning, several valuable lessons emerged from the experience. As highlighted during the workshop discussions, effective dengue control—particularly larval source management—requires a multi-sectoral approach. For example, Aedes mosquitoes often breed in artificial containers that fall under the responsibility of different sectors, such as road maintenance crews for potholes or port authorities for harbor areas.

Another critical area for improvement is the integration of entomological data into a digital infrastructure. Currently, much of this data is collected on paper, limiting its accessibility and use for coordinated control efforts. Digitizing these records would enhance monitoring, analysis, and intervention strategies.

Additionally, dengue prediction models could be further refined by incorporating mobility patterns and socio-economic census data, offering a more comprehensive understanding of how the disease spreads and where interventions could be most effective.

By continuously enhancing the digital tools developed through the E4Warning project, we aim to support the Sri Lankan National Dengue Control Unit (NDCU) in achieving its ambitious goals for dengue control and prevention.

Our partner and WP leader, Rachel Lowe, ICREA Research Professor and Global Health Resilience (GHR) Group Leader at the Barcelona Supercomputing Center (BSC), was recently interviewed by HERA (Health Emergency Preparedness and Response Authority) and featured on their website: https://ec.europa.eu/newsroom/hera/items/852413/en

HERA is an EU body established to strengthen Europe’s ability to anticipate and respond to health emergencies, particularly in the wake of the COVID-19 pandemic. It aims to ensure the provision of critical medical countermeasures and enhance Europe’s readiness for future health threats.

In the interview, Rachel Lowe discusses the intricate connections between climate change and the outbreaks of climate-sensitive infectious diseases, exploring why these outbreaks are increasing and spreading to new regions, particularly in Europe. She also explains how shifting climate patterns could influence emergency preparedness and response strategies, highlighting the need for proactive, integrated approaches. She shared insights into specific climate-sensitive diseases that pose a potential threat to the EU, including dengue, chikungunya, and West Nile virus, and discussed ongoing efforts like the development of the EpiOutlook platform within the IDAlert project, which is part of the European Climate-Health Cluster. This platform aims to provide early warnings of climatic suitability for various infectious diseases in Europe. They also track the impact of climate change on these diseases in the Lancet Countdown in Europe collaboration.

As part of E4Warning, Professor Lowe also elaborated on her work in developing decision support tools like the D-MOSS (Dengue forecasting Model Satellite-based System) for dengue in endemic regions in collaboration with HR-Wallingford, as well the efforts on integrating different data sources such as citizen science initiatives like Mosquito Alert, which could enhance the monitoring and management of disease vectors across Europe, providing critical support for future public health interventions.

For more details, read the full interview on the HERA website and gain valuable insights into how E4Warning and its partners are addressing the growing challenges posed by climate-sensitive diseases in Europe.

In a recent study conducted in Brazil by researchers from the Instituto Oswaldo Cruz, the E4Warning project successfully deployed smart traps with the VECTRACK sensor developed by IRIDEON, to improve mosquito surveillance in urban settings. These smart traps, equipped with AI and IoT technologies, have been tested in two Brazilian cities—Rio de Janeiro and Brasilia—where they demonstrated high accuracy in identifying mosquito species such as Aedes aegypti and Culex quinquefasciatus, both key vectors for diseases like dengue, Zika, and chikungunya.

Over a year of field testing, the traps showed a remarkable 99.8% accuracy in distinguishing target mosquito species from other insects and a 93.7% accuracy in differentiating between the two genera of mosquitoes. The smart traps collected data on 9,151 insect flights, of which 1,383 were mosquito vectors.

These findings indicate the potential of the E4Warning tool to provide real-time monitoring and classification of mosquitoes in areas with high vector-borne disease risks: by the end of September 2024, over 9.5 million dengue cases had been reported in Brazil. In this context, the data gathered from the smart traps could be instrumental in aiding public health authorities to make timely interventions, such as targeted vector control measures, enhancing the preparedness and response to mosquito-borne disease outbreaks.  The successful implementation of the IRIDEON smart traps in Brazil showcases how cutting-edge technologies can revolutionize mosquito surveillance, making it faster, more accurate, and less reliant on manual labor.

The paper has been published in the Parasite & Vector journal: Njaime, F.C.B.F.P., Máspero, R.C., Leandro, A.d., Maciel-de-Freitas, R. Automated classification of mixed populations of Aedes aegypti and Culex quinquefasciatus mosquitoes under field conditions. Parasites Vectors 17, 399 (2024).

It can be consulted at the following link: https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-024-06417-z

It can also be founded in the E4Warning Zenodo community: https://zenodo.org/records/13868673

Eva Veronesi (SUPSI) attended the 6th International Workshop on Aedes albopictus in Phnom Penh, Cambodia, from March 28-29, 2024. Organized by the Institute Pasteur of Cambodia, the workshop was led by Dr. Sébastien Boyer (head of the Medical and Veterinary Entomology Unit at the Institute). The opening session was presided over by Prof. André Spiegel, Director of the Institute Pasteur of Cambodia, with the presence of Professor Chheang Ra, Minister of Health of Cambodia, Mr. Jacques Pellet, Ambassador of France to Cambodia, and Dr. Boyer, who delivered the introductory talk.

The Aedes albopictus, commonly known as the tiger mosquito, is a principal carrier of Dengue fever, Chikungunya, Zika, and at least 20 other significant pathogens impacting public health. Originating from the tropical and subtropical zones of Southeast Asia, the tiger mosquito has expanded its reach globally over the last century, facilitated by international trade and travel. Distinguished by distinctive white stripes on its legs and body, the species has adapted well to human environments. As a considerable nuisance, the tiger mosquito typically resides close to human habitats and is known for its daytime biting behavior, especially during early morning and late afternoon periods.

The event was focused on enhancing scientific collaboration and showing innovative vector control strategies. Key research topics covered included vector models of invasion and dispersal, and the role of the species as a bridge vector, including the influence of climate change on vector behavior. For that, the workshop unfolded five sessions:

• Aedes albopictus in Asia.
• Biology and Ecology of Aedes albopictus.
• Vector control: challenges and innovations.
• Vector control: insecticide resistance.
• New surveillance strategies.

It was during the session on innovative surveillance strategies that E4Warning was spotlighted. The presentation titled “The Role of E4Warning in Combating the Spread of Dengue in Asia and its Potential Incursion into Europe” by Eva Veronesi showcased to the audience the surveillance tools involved in the project, such as Mosquito Alert (CSIC, UPF), VECMAP (AVIA-GIS)  and the smart traps designed by IRIDEON. Additionally, it highlighted the dengue models developed by the Barcelona Supercomputing Center (BSC) and HR Wallingford.

Link to the agenda of the event: Agenda 6th International Workshop on Aedes albopictus

E4Warning participated in the high-level conference “Research Perspectives on the Health Impacts of Climate Change,” organized by the Directorate-General for Research and Innovation (DG RTD) of the European Commission. This event, held in Brussels on February 19th and 20th, 2024, aimed to highlight the crucial nexus between climate change and global health issues.

Chloe Fletcher, a PhD candidate from the Global Health Resilience group at the Barcelona Supercomputing Center (BSC), attended the conference. Her research focuses on developing statistical models for predicting outbreaks of climate-sensitive infectious diseases, such as dengue and leptospirosis. Fletcher presented a poster titled “A Generalized Modelling Framework for Dengue Early Warning Systems in South and Southeast Asia,” a collaborative effort involving Ramy Hoek Spaans (BSC), Sophie Belman (BSC), Chloe Fletcher (BSC), Quillon Harpham (HRW), Gina Tsarouchi (HRW), and Rachel Lowe (BSC), all contributing to the E4Warning project.

This study aims to broaden the successful application of the Dengue Forecasting Model Satellite-based System (D-MOSS), originally implemented in Vietnam, to include Sri Lanka and Malaysia. By employing a Bayesian modeling approach and contrasting it with the conventional practices of dengue outbreak monitoring in each nation, the research seeks to identify which dengue predictors remain consistent or vary across these diverse regions.

The goal is to establish a universally applicable template for developing dengue early warning systems. The D-MOSS platform, which underpins this forecasting system, is managed by HR Wallingford. A key ambition of E4Warning is to collaborate intimately with local partners to deliver actionable data visualizations, thereby enabling an informed, data-driven approach to dengue management.

You can view the summaries of other posters presented during the conference at this link.

The early warning system for dengue fever in Vietnam, developed by D-MOSS as part of the E4Warning initiative, has been highlighted as a significant success story during the launch of the World Meteorological Organization’s (WMO) “Climate Services for Health” report launched the past 2th November 2023. Rachel Lowe from the Barcelona Supercomputing Center (BSC) represented the project, elaborating on the vital work performed by E4Warning.

The presentation underscored how this advanced system is making strides in public health by providing early warnings of dengue fever outbreaks. By harnessing climate data and predictive modeling, the system is aiding Vietnam in taking preemptive measures to mitigate the impact of this vector-borne disease, thereby safeguarding communities and strengthening the resilience of health systems.

The latest World Meteorological Organization’s (WMO) State of Climate Services report delivers a compelling message about the intricate connection between our changing climate and public health. The report acts as a clarion call, highlighting the dire need for precise climate information and services to bolster the health sector amid escalating threats from extreme weather events, evolving disease patterns, and the looming specter of food and water scarcity.

Prof. Petteri Taalas, WMO Secretary-General, brings to the forefront the widespread occurrence of heatwaves across the globe, further intensified by the imminent onset of El Niño. This scenario sets a backdrop for heightened temperature records, amplifying the urgency for increased investment and collaborative efforts to elevate the role of climate science. By doing so, health partners can gain critical support in times when our climate’s unpredictability takes a tangible toll on human health.

In alignment with Prof. Taalas’s observations, WHO Director-General Dr. Tedros Adhanom Ghebreyesus defines the climate crisis as an escalating health crisis. He underlines the vital need for access to high-quality climate services within the health sector to counteract the perilous effects of climate change on human well-being.

Despite this clear need, the report reveals a gap: climate data often does not permeate health decision-making processes as it should. This disconnect points to an essential requirement for improved early warning systems, especially since disaster events are anticipated to surge, with less-prepared countries facing significantly higher mortality rates.

The focus then shifts to the underestimation of extreme heat’s health impacts. Highlighting the efforts of the Early Warnings for All initiative, the report underscores the necessity to expand heat warning services, which are currently absent in many vulnerable regions.

Ultimately, the WMO report connects the dots between the adverse effects of climate change on various aspects of health — from the quality of the air we breathe to the nutritional security of our food and the control of infectious diseases. It’s a comprehensive wake-up call for cross-sectoral action, aiming to fortify the health community against the multifaceted challenges posed by a warming world. This post serves to emphasize that climate action is not just an environmental imperative but a crucial facet of global health strategy.

Tangible solutions

The World Meteorological Organization’s (WMO) State of Climate Services report doesn’t just outline the challenges; it showcases tangible solutions through success stories where climate services have made significant inroads in health outcomes. One such example is the early warning system for dengue in Vietnam, which was presented as a beacon of the potential benefits of climate services for health. This system, alongside other initiatives from Africa, Europe, the Pacific, and the Pan-American region, represents the strides being made in marrying meteorological insights with health sector needs.

The State of Climate Services report can be downloaded here.