Much of Europe presents a broad risk of transmission of the Chikungunya virus and Portugal is part of the area where this possibility is greatest, warned a study by the United Kingdom’s Center for Ecology and Hydrology.
The Chikungunya virus, responsible for a debilitating tropical disease caused by the bites of infected mosquitoes, represents a “greater health threat in Europe than previously thought, as it can be transmitted when air temperatures are as low as 13 degrees Celsius”, concluded research published this Wednesday, February 18, in the scientific journal The Royal Society.
In practice, the new study revealed that the virus can transmit at temperatures of just 13 to 14 degrees Celsius, unlike previous research that indicated a minimum of 16 to 18 degrees, revealed the independent research institute with around 600 researchers from various areas.
This means there is a risk of local Chikungunya outbreaks in more areas and for longer periods of time than previously thought, warned researchers, who created a map for Europe with three risk levels – high, moderate and low.
Portugal falls into the highest risk area, along with countries such as Greece, Italy, Malta and Spain, with the study predicting that transmission can occur for around six months of the year.
The risk gradient is greatest in the southern regions of Europe, decreasing as one moves to the north and northwest, the study also concluded, warning that approximately 50% of Europe’s geographic area is now prone to transmission during July and August.
In 2025, there will be record numbers of local Chikungunya outbreaks in France and Italy and the tiger mosquito (Aedes albopictus) has also been responsible for the increase in dengue cases in these countries in recent years.
Researchers have warned that as Europe is warming rapidly due to climate change, the tiger mosquito is gradually expanding north of the continent.
“The lower temperature threshold we have identified will result in more areas – and more months of the year – potentially suitable for transmission” of the virus, highlighted Sandeep Tegar, an expert at the UK research center who led the study, emphasizing that warmer weather also increases the rate of virus replication in an insect’s body, thus increasing the risk of transmission.
The first known outbreak of Chikungunya was reported in Tanzania in 1952, but the virus currently affects public health in more than 110 countries in Asia, Africa, Europe and the Americas.
Identifying specific locations and months of possible transmission will allow local authorities to decide when and where to act to reduce the risk or scale of outbreaks, highlighted Sandeep Tegar.
In November 2025, the president of the National Health Institute Ricardo Jorge (INSA), the institution that officially coordinates the Vector Surveillance Network, highlighted that Portugal is prepared to respond to possible emergencies caused by diseases transmitted by mosquitoes and ticks.
Fernando Almeida told Lusa that Revive – Vector Surveillance Network has around 350 employees across the country, ensuring the early detection of vectors transmitting diseases such as Zika, Dengue and Chikungunya, at a time when the Aedes albopictus mosquito is already widespread throughout almost the entire country.
Revive’s 2024 report indicated that the mosquito species in question was detected, from 2017, in the North, Algarve, Alentejo and Lisbon and, in 2024 for the first time, in the Center, which points to a “situation of establishment and geographic dispersion” across several regions of the country.
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