A new scientific study indicates the tiger mosquito, already established across much of Europe, could transmit chikungunya in Belgium at temperatures previously thought too low for the virus to develop. The findings, published February 18, 2026, in the Journal of the Royal Society Interface, suggest local transmission during the summer months is now a possibility.
Researchers previously believed a minimum temperature of 16 to 18°C (61 to 64°F) was required for the mosquito to effectively transmit chikungunya, with the virus having an average lifespan of 8.7 days within the insect. However, the new study demonstrates the virus can now thrive at temperatures as low as 13.8°C (56.8°F), with optimal transmission occurring around 25.6°C (78°F). This lower threshold significantly expands the potential geographic range and timeframe for outbreaks.
The expansion of the tiger mosquito population in Europe is linked to climate change, with outbreaks already reported in Italy and southern France. More recently, cases have been detected in Paris and the Vosges region. While, as of February 19, 2026, Belgium has only recorded imported cases of chikungunya – contracted by travelers returning from affected regions – the increasing presence of the mosquito within the country is raising concerns among health specialists.
Chikungunya, while rarely fatal, can cause debilitating illness. Steven Van Den Broucke, a specialist in infectious diseases at the Institute of Tropical Medicine, explained the disease progresses in two phases. “The first is characterized by flu-like symptoms and a high fever, potentially reaching 40.5 degrees Celsius,” Van Den Broucke said. “Muscle and joint pain, headaches, and sometimes a rash can as well occur. This acute phase typically lasts about a week.”
A second phase can follow, marked by persistent joint pain and inflammation. “Patients often complain of morning stiffness, generally in the ankles, knees, hands, or wrists,” Van Den Broucke added.
Sciensano, the Belgian institute for health, is actively monitoring the presence of the tiger mosquito across the country to anticipate potential virus outbreaks. The mosquito was first detected in Belgium in 2025, with confirmed overwintering in several municipalities, including Hoegaarden in Flemish Brabant. The presence of the mosquito is also being monitored in neighboring areas, as adults typically travel no more than 100-150 meters.
The Belgian Federal Agency for Medicines and Health Products (AFMPS) notes that, until recently, only imported cases of chikungunya were diagnosed in Belgium. The agency currently has no vaccine or specific treatment for the virus, only supportive care.
