The World Health Organization (WHO) has cautioned that dengue fever, which is transmitted by mosquitoes, has surfaced in Spain.

The World Health Organization (WHO) has issued a warning about the arrival of dengue fever, a mosquito-borne virus, in Spain. The mosquito responsible for transmitting dengue fever is known as the tiger mosquito or 'Aedes albopictus'. This species is native to Southeast Asia's tropical rainforests but has spread around the world over the past few decades due to factors such as global travel and climate change.

The Spanish Ministry of Health has confirmed that the tiger mosquito is now present throughout the Spanish Mediterranean area and the Balearic Islands, as well as inland and northern parts of the country. The mosquito is most active between May and November, and the risk of new cases in Spain during that period is considered moderate.

The tiger mosquito is black, with a distinctive white stripe on the thorax and striped legs. It measures between 2 and 10 millimetres and prefers humid areas and rural environments with dense vegetation, although it can also be found in urban environments where it can find water. The mosquito is known to move from one area to another through vehicles.

Symptoms of dengue fever include high fever, severe headache, muscle and joint pain, nausea, vomiting, rash, and pain behind the eyes. Between 40% and 80% of dengue cases are asymptomatic, but if it does cause symptoms, they are similar to those of the flu. Only 5% of infections lead to severe dengue or dengue haemorrhagic fever, which can be life-threatening, especially for vulnerable patients such as children, the sick, or the elderly.

The WHO and the Carlos III Institute in Madrid have both issued warnings about the increasing risk of dengue fever due to factors such as global travel, migration, and climate change. The WHO's technical head of the global program for the control of tropical diseases, Diana Rojas, has stated that climate change has accelerated the spread of the tiger mosquito, and the increase in the number of countries where the mosquito has become established is alarming. She has also emphasized the need for preparedness and vigilance in the face of this emerging threat.