West Nile virus reported in 12 European countries

Twelve countries in Europe have reported locally acquired cases of West Nile virus so far this year, the European Centre for Disease Prevention and Control said Friday as it urged stronger mosquito-control efforts.

The Stockholm-based EU health agency said cases had been reported in 99 regions in Albania, Austria, France, Germany, Greece, Italy, Kosovo, the Netherlands, North Macedonia, Romania, Serbia and Spain.

Italy and Greece had the highest number of cases, with 311 and 157 respectively. The ECDC said 21 regions across Europe had reported their first ever cases. By comparison, 67 regions in nine European countries had reported cases during the corresponding period in August 2025.

West Nile virus is mosquito-borne. It can cause flu-like symptoms and, in extreme cases, tremors, fever, coma, encephalitis or meningitis.

Celine Gossner, the ECDC's head of food-, water-, vector-borne and zoonotic diseases, said the spread of West Nile virus transmission and invasive mosquito species showed why Europe needed to strengthen mosquito-control capacity.

Most human infections in Europe occur during mosquito season, which generally runs from late spring to autumn and peaks between July and September.

The World Health Organization says there are no approved human vaccines and no specific treatments for West Nile virus. Care is limited to symptom management and supportive hospital treatment for severe cases.

The ECDC said Culex mosquitoes, which spread West Nile virus, are already widely present in Europe. It also said the Asian tiger mosquito, which can transmit dengue and chikungunya, is now established in 16 European countries, double the number from 12 years ago.