European officials have warned that the continent is seeing "record breaking outbreaks" this summer of the mosquito-borne illnesses West Nile virus and chikungunya. Countries affected include Spain, Portugal, Cyprus and France, as well as other parts of mainland Europe.

One of the main reasons behind the increase is that the mosquito season is becoming "longer and more intense" as a result of global warming. Rising temperatures, milder winters and shifting rainfall patterns are creating the perfect conditions for mosquitoes to thrive and spread the viruses, according to the European Centre for Disease Prevention and Control (ECDC). Mosquito-borne illnesses could become endemic in Europe as a result, health and climate scientists have warned. The mosquito that spreads chikungunya, known as Aedes albopictus or Asian tiger mosquito, has now been found in 16 European countries and 369 regions, up from 114 regions a decade ago. 

So far this year, 27 cases of the virus have been reported, which is a new record for Europe the ECDC said. At the same time, there have been 335 cases of West Nile virus, the highest level in three years.

The virus is spreading to new regions on the continent, including Sălaj County in Romania and the Latina and Frosinone provinces of Italy, where at least 10 people have died.

In Spain, Sevilla province has recorded the highest number of West Nile virus cases in Andalucia, with the villages of Puebla del Rio and Coria del Rio along the Guadalquivir River being particular hotspots. Outbreaks have also been detected across Cadiz, Huelva, Cordoba, Malaga and Jaen provinces.

Celine Gossner, head of the ECDC’s vector-borne diseases section, said: "As the landscape of mosquito-borne diseases evolves, more people in Europe will be at risk in the future. This makes prevention more important than ever."

Infections typically peak from July to September, so health officials are expecting the number of cases to rise accordingly.

Chikungya symptoms include fever, muscle and joint pain, as well as itching. Most infected people recover, but a third of those infected may develop chronic arthritis.

Those infected with the West Nile virus typically suffer from sudden high fever, severe headache, body aches, nausea, vomiting and a rash. In severe cases, patients may become paralysed or fall into a coma, although this is rare.

Chikungya, in particular, has been making headlines around the world, as infections once again surge. In China, more than 7,000 cases were reported in Guangdong province this year, with almost 3,000 new infections in the last week.

Although there have been no incidents of local transmission in Spain this year, there were imported cases. An autochthonous case of chikungunya was also reported in July in Hendaye (France), near the Spanish border .