You open your eyes one summer morning and discover several bites on your skin. Days later, you have a high temperature, feelings of nausea and your joints are incredibly painful. At the doctor’s, you receive a disturbing diagnosis: dengue fever. “But isn’t that an exotic disease?” you wonder. The answer is obvious: not anymore.

Although it may sound like the beginning of a dystopian novel, this could actually happen where you live. In Spain, for instance, there have been reports of some indigenous cases of tropical diseases that, until recently, had never set foot on European soil. However, what’s most worrying is that these aren’t isolated incidents but signs of a far-reaching change. 

“Some of these diseases used to occur sporadically, such as West Nile virus, but now they’re endemic. Others, such as dengue, Zika and chikungunya, arrive as imported cases and cause sporadic small outbreaks in Europe” says Jordi Figuerola, a CaixaResearch researcher at the Doñana Biological Station (CSIC) and CIBERESP.

Jordi Figuerola, a CaixaResearch researcher at the Doñana Biological Station (CSIC) and CIBERESP.

As with any health emergency, understanding why it’s happening is essential in order to tackle it. “Population growth and deforestation are altering the habitat of animals capable of spreading tropical diseases. Added to this are climate change and international travel, which help to spread pathogens and insect vectors, such as mosquitoes and ticks” explains Jose Muñoz, head of the International Health Service at Hospital Clínic and a researcher at ISGlobal.

“To prevent their spread, it’s not enough to know where the pathogens are but also which vectors inhabit each area and how they interact with animals and humans. If we reduce the vector, we reduce the chances of infection” adds Aitana Oltra, a “la Caixa” Foundation fellow and specialist in science management at CEAB-CSIC, as well as co-founder of the Mosquito Alert project, with support from CaixaResearch. 

In countries where these diseases are endemic, there are control programmes tailored to each case, such as impregnated nets for the mosquito that transmits malaria. In Europe, on the other hand, the strategy consists of preventing such diseases from establishing themselves and starting transmission cycles.

José Muñoz’s team is developing a surveillance model called FAMBA, based on international travel. “It’s a remote medical system for travellers that collects real-time health data, analysing this information with artificial intelligence to detect emerging diseases at an early stage” he explains. “Our goal is to perform a proof of concept at a European level to demonstrate its effectiveness”.

Jose Muñoz, head of the International Health Service at Hospital Clínic and a researcher at ISGlobal.

The research carried out by Jordi Figuerola, on the other hand, focuses on West Nile virus, whose incidence continues to rise in Spain, with 158 cases and 20 deaths in 2024. “Our aim is to produce predictive models for the number of mosquitoes and risk of virus transmission to improve control. Thanks to our work, we’ve discovered new vector species and detected the circulation of the virus a month before the first human cases appeared”. 

Citizen involvement also plays a key role in monitoring viruses and vectors, as demonstrated by the Mosquito Alert app. “Thanks to the participation of society and new technologies, the platform can collect data and photos on mosquito vectors in Europe almost in real-time, even detecting new species in places where they were previously unknown. This information enables control protocols to be activated quickly” notes Aitana. 

Citizen involvement has greatly enriched data collection and has speeded up vector detection in large areas, overcoming the limitations of traditional methods. In addition, “an informed and active society is better prepared to implement control measures and understand the complexity of the problem” adds Aitana.

Aitana Oltra, a “la Caixa” Foundation fellow and specialist in science management at CEAB-CSIC, as well as co-founder of the Mosquito Alert project, with support from CaixaResearch. 

Indeed, while the research progresses, there’s also a lot that can be done to prepare the public for this new threat. “Our protection starts at home: emptying containers with standing water where mosquitoes can breed, such as saucers under plant pots or air conditioning units. It’s also a good idea to cover windows with mosquito nets and, in areas where this insect is abundant, wear long sleeves and repellents” says Jordi.

“The most important thing is to follow the instructions issued by the public health authorities. In summer, for example, there’s a higher density of tiger mosquitoes and more cases of dengue fever are diagnosed in our country” warns José.

The map of infectious diseases is constantly evolving but experts are clear on one thing: science, prevention and the active involvement of society are key. Only then can we anticipate risks, be better prepared and avoid worrying scenarios such as the one described at the beginning of this article.