Climate change is encouraging the insects to spread across Europe, leading to outbreaks in diseases like dengue fever and West Nile virus.
A Valencia lab sterilises 45,000 tiger mosquitoes weekly to combat dengue and Zika. Photo: ReutersA Spanish laboratory is breeding and sterilising thousands of tiger mosquitoes to combat the rapid spread of dengue fever and other diseases. The increasing prevalence of these diseases in Europe, fuelled by climate change, necessitates immediate and concerted efforts.
Using an advanced electron accelerator, the regional government-funded Biological Pest Control Centre in Valencia successfully sterilises and releases about 45,000 male mosquitoes weekly. They can then pair with females – whose bite transmits diseases among humans – and eventually reduce the overall mosquito population (see graphic).
Dengue viruses are spread to people through mosquito bites of infected Aedes species. These are the same types of mosquitoes that spread Zika and chikungunya viruses. Mosquitoes become infected with dengue when they bite a person infected with it. Infected mosquitoes can then spread the virus to other people through bites.
“[Tiger mosquitoes are] ... becoming more common with climate change ... There is a favourable environment for its development for longer periods throughout the year, and its populations are increasing all the time,” said Vicente Dalmau of Valencia region’s health, agriculture and fisheries department.
The specimens for reproduction come from the region, and scientists then use a machine to separate female pupae from the males before sterilising the males.
Sterilisation techniques have been used in other parts of the world. Still, using its experience with fruit flies, the lab is pioneering their use of tiger mosquitoes in Europe at a time of growing concern over a rise in mosquito-borne diseases such as dengue, Zika and chikungunya.
Data from the European Centre for Disease Prevention and Control shows an increase in cases imported from regions where dengue is endemic and an increasing number of local outbreaks of West Nile virus and dengue in Europe.
The striped tiger mosquito, or Aedes albopictus, is spreading north, east, and west in Europe and now has self-sustaining populations in 13 countries, including Spain.
The World Health Organization said last year that dengue rates were rising globally, with reported cases since 2000 up eightfold to 4.2 million in 2022, as a warmer climate is thought to help the mosquitoes multiply faster.
Reuters
Why do mosquitoes always bite me and not my friends?
How can I tell the different species of mosquito apart?
There are more than 3,500 mosquito species worldwide, but only a few can spread diseases.
Here are three of the more common ones:
Aedes mosquitoes can transmit diseases like dengue, Zika, yellow fever, and chikungunya. They often live outdoors, near houses or forests, and are commonly found in cities. Aedes mosquitoes bite during the day, usually in the early morning and late afternoon. They have black bodies with white or silver patches on their legs and other parts of their bodies.
Anopheles mosquitoes spread malaria. During the day, they prefer to rest in dark, quiet places. They usually bite people at night, often late in the evening. Anopheles mosquitoes have long, thin palps near their mouths that are about the same length as their main mouthpart.
Culex pipiens mosquitoes can spread the Japanese Encephalitis virus, West Nile virus, Usutu virus, and a few others. They can be found in places with cooler weather and often live near homes. Culex pipiens mosquitoes typically bite between dusk and dawn. Their bodies are usually brown without any unique markings.