The appearance and expansion of Aedes aegypti and Aedes albopictus mosquitoes in national territory, capable of transmitting diseases such as dengue, Zika, and chikungunya, represent a growing challenge for public health in Portugal. As a researcher at the GIMM Foundation who works directly with these mosquitoes and the diseases they transmit, I believe this reality should be taken seriously, without alarmism, but with the awareness that action is necessary to avoid more complex scenarios in the future.

Aedes aegypti, present in Madeira, has already demonstrated its impact with the dengue outbreak of 2012–2013, while Aedes albopictus has been consolidating its presence in mainland Portugal, having been recently detected in Lisbon and the Algarve. Both are proven vectors of diseases such as dengue, Zika, and chikungunya, and their presence requires an integrated response between science, health authorities, and society.

Science and surveillance as essential tools

The risk of transmission of these viruses does not depend solely on the presence of the mosquito. It is necessary for a person already infected with one of these viruses in Portugal to be bitten by the mosquito, which must then transmit the virus to other people. However, with the increase in international travel and climate change, this risk is becoming more present.

Epidemiological and entomological surveillance is, therefore, an essential pillar. The early identification of suspected cases and the monitoring of mosquito populations make it possible to anticipate potential outbreaks and adopt effective preventive measures. We must act preventively, not just when outbreaks occur.

In Portugal, the REVIVE program (Vector Surveillance Network), coordinated by the National Institute of Health Dr. Ricardo Jorge (INSA), plays a crucial role in this effort. Through continuous monitoring of mosquito populations, early detection of invasive species, and the assessment of disease transmission, REVIVE enables a faster and better-informed response. This type of initiative, based on science and concrete data, is essential to ensure that control and prevention strategies are effective and adapted to the national reality.

At the GIMM Foundation, we study mosquito biology and the mechanisms that enable virus transmission, with the aim of developing innovative strategies for controlling viral infections transmitted by these insects. Our research focuses on approaches such as the introduction of a bacterium that prevents mosquitoes from transmitting viruses (Wolbachiabacteria), the development of new antiviral molecules that can reduce virus spread, and the study of mosquito resistance to insecticides, allowing the creation of more effective and sustainable control methods. These scientific advances are fundamental to combating the growing threat posed by vector mosquitoes in Portugal and worldwide.

The role of collective responsibility in mosquito control

Institutional and scientific efforts are fundamental, but there is an essential component in this equation: individual and collective responsibility. Aedes aegypti and Aedes albopictus reproduce in small amounts of standing water, often in backyards and balconies. Each of us can contribute to reducing their presence by eliminating potential breeding sites, such as plant saucers, pet water bowls, poorly sealed water reservoirs, or accumulated debris.

Moreover, citizen science platforms such as MosquitoWeb and MosquitoAlert allow anyone to contribute to monitoring the spread of these insects by identifying and recording suspected mosquitoes. With these tools, citizens can take photos and send them to specialists who validate the presence of invasive species, helping to map their distribution in real time. This type of active participation strengthens the responsiveness of health authorities and the scientific community, enabling quicker and more targeted interventions.

Raising public awareness about adopting preventive measures can make a significant difference. If we reduce the conditions favorable to the proliferation of these mosquitoes and contribute to their early detection, we are tackling the problem at its root. Prevention, in this case, as in many others, is more effective and economical than responding to a viral outbreak.

The balance between caution and action

As a researcher, I cannot ignore that there is a delicate balance between informing the population and avoiding unnecessary panic. The presence of these mosquitoes in Portugal does not immediately mean disease outbreaks, but we also cannot dismiss the warning signs.

We need a coordinated approach, based on the best available scientific evidence, where public health, research, and society work together to mitigate risks before they become crises. Science has already shown us that there are innovative ways to control mosquito populations without aggressive environmental impacts. It is now up to us to ensure that these strategies are adopted and effectively applied.

Portugal now has an opportunity to act before facing a more complex situation. Investing in surveillance, research, and public awareness are the first steps to ensuring that these vectors do not become a greater threat.

Gonçalo Seixas

Researcher, Nuno Santos Lab