West Nile virus spreads in Europe and has already caused 130 deaths this year

West Nile virus, transmitted by mosquitoes, has been diagnosed in 1,715 people this year in the European Union, the highest number ever recorded. The infection has caused 130 deaths, 7.6% of the cases. These are data from an epidemiological report on the disease published today by the European Center for Disease Prevention and Control (ECDC).

Spain, with 139 diagnoses and 6 deaths, is the fourth most affected country in number of cases and fifth in mortality. In Europe as a whole, the two most affected countries are Italy (with 748 cases and 56 deaths), Greece (445 cases and 46 deaths) and France (144 cases and 3 deaths).

West Nile virus is transmitted to people through the bites of Culex mosquitoes, primarily the common mosquito (Culex pipiens). On the contrary, the tiger mosquito, of the genus Aedes, does not transmit it. For contagion to people to occur, the mosquito must first have bitten an infected bird. But, if a mosquito bites an infected person, it cannot then transmit it to another person. For this reason, the virus appears in isolated cases and cannot cause major epidemics.

Only around 20% of infected people get sick, while the other 80% are asymptomatic. The 1,715 cases diagnosed this year in the EU indicate that the real number of infections may be around 10,000.

The infection can cause headache, muscle or joint pain, eye pain, vomiting, diarrhea or skin rashes, as well as fever. In a minority of cases the virus affects the nervous system and causes serious complications that can be fatal such as meningitis or encephalitis.

“West Nile virus is expanding to new areas of Europe,” the ECDC warned today in a statement. “Recent detections in people and animals in Belgium and the Netherlands indicate that it is now circulating further north, a trend that is expected to continue in the coming years.” The virus, which years ago had not reached Europe, has been endemic in Catalonia since the beginning of this decade. Climate change has favored mosquitoes that transmit the infection, which have longer breeding seasons and are active for more months of the year.

Although infections will reduce with the arrival of autumn, “additional cases are still expected in the coming weeks,” says the ECDC, which urges European governments to adopt “prevention, surveillance and control measures of mosquito populations.”

For citizens, it recommends “using mosquito repellent, wearing loose clothing that covers the body during dusk and at night, and using mosquito nets on the windows, protective nets or air conditioning.” According to the ECDC, these measures are “especially important for older people or people with weakened immune systems, as they are at greater risk of suffering severe symptoms” if they contract the infection.