A Spanish lab is breeding and sterilizing thousands of tiger mosquitoes in a bid to fight dengue fever and other diseases as climate change helps the invasive species spread across Europe.

Using an electron accelerator, the regional government-funded Center for Biological Pest Control in Valencia sterilizes and releases about 45,000 male mosquitoes each week so they can mate with females – whose bites transmit disease to humans – and ultimately reduce the overall mosquito population.

“This is a species that is increasing with climate change… There is a favorable environment for its growth for longer periods of time throughout the year and its populations are constantly increasing“, said Vicente Dalmau from the Health, Agriculture and Fisheries Service of the Region of Valencia.

Specimens for breeding are taken from the area and scientists then use a machine to separate the female nymphs from the males, before using radiation to sterilize the males.

Sterilization techniques have been used in other parts of the worldbut the Spanish lab, using its experience with fruit flies, is pioneering the use of the techniques on tiger mosquitoes in Europe at a time of growing concern about the rise of mosquito-borne diseases such as dengue, Zika and chikungunya.

Data from the European Center for Disease Prevention and Control show an increase in cases imported from areas where dengue is endemic, as well as an increasing number of local cases of West Nile virus and dengue in Europe.

The tiger mosquito, (scientific name Aedes albopictus) is spreading north, east and west in Europe and now has self-sustaining breeding populations in 13 countries, including Spain.

The World Health Organization said last year that dengue rates were rising worldwide, with reported cases since 2000 set to rise eightfold to 4.2 million in 2022, as warmer temperatures are thought to help mosquitoes multiply faster.