European West Nile Virus Outbreak Intensifies: 69 Local Cases, 8 Countries on Alert, Potential Outbreak Period in Coming Months

As of 31 July 2024, a total of 69 local cases of West Nile virus infection have been reported in eight countries in Europe. Specifically, 31 cases have been reported in Greece, 25 in Italy, 5 in Spain, 2 each in Austria and Hungary, 1 each in Serbia and France, and 1 in Romania. Of those cases, eight deaths have each been reported in Greece, Italy and Spain.

Europe-wide, the total number of cases reported so far this year is in line with expectations, although the number of cases in Greece and Spain has exceeded previous years. Indicators of clinical presentation and severity remained consistent with previous years. All of the areas affected this year have either had previous cases or are adjacent to areas where cases have been reported.

Given the favourable climatic conditions for West Nile virus transmission in Europe, the number of human cases is expected to increase in the coming weeks and months.

West Nile virus is mainly transmitted through mosquito bites. Transmission is most common in birds, but humans and mammals can also be infected. About 80 percent of infected people do not develop any symptoms. Most human cases occur between July and September, when mosquito activity is high.

The widespread geographical spread of West Nile virus in Europe is attributed to the large number of Culex mosquitoes that transmit the virus. This mosquito is native to Europe and is now found throughout the continent.

About 20 percent of people infected with West Nile virus develop West Nile fever symptoms, which include headache, malaise, fever, vomiting and fatigue. Less than 1% of those infected are likely to develop severe disease that affects the nervous system.

To prevent WNV infection, individuals can take the following precautions: use mosquito repellent, wear clothing that covers most of the body, and sleep in a shielded or air-conditioned room.