The European Center for Disease Prevention and Control (ECDC) has announced that the number of infection with West Nile virus in Europe, registered in 2025 to August 6, is slightly above the average of the last decade. Six European countries reported 202 cases acquired locally, among them Romania.
Confirmed cases of West Nile infection.
In the last epidemiological summary of ECDC, it is mentioned that six countries in Europe have reported 202 cases of infection with the West Nile virus in humans, with a well -known infection. The first case was reported on June 2.
Italy is the country with most cases acquired locally – 168, followed by Greece – 26, France – three (a case with unknown infection), Romania – three, Bulgaria – one case, Hungary – a case. There were reported in Europe and 10 deaths.
“The number of cases reported so far this year is slightly above the average of the last decade of the same period (163). However, these figures remain lower than those observed in 2024 and 2018 – years in which the circulation of the virus was particularly intense, with 382 and 385 cases reported until this time of year ””ECDC shows. Until August 6, 40 regions of the six mentioned European countries reported locally acquired cases, compared to 10 regions (out of 11 countries) in the same period of 2024 and 68 regions (from seven countries) in 2018, these being the years with a strong circulation of the virus and with numerous infections.
In Italy, the most worrying situation is recorded, being 168 confirmed human infections, including 10 deaths. Two regions of Italy, Latin and Frosinone, reported confirmed human cases for the first time. Similarly, Romania reported the first cases in Sălaj County, ECDC mentions.
All cases required hospitalization
“As observed in previous years, most cases have been among men aged 65 and over. The hospitalization rate has been raised compared to previous years, 100% of cases being hospitalized this year, compared with 93% in the last decade. The fact that most cases are hospitalized is most likely due to the nature of West Nile virus surveillance, which tends to predominantly capture the most serious cases. The mortality rate so far this year is 7%, comparable to 11% observed in the previous decade ”, It is mentioned in the report of the European Center for Disease Supervision.
Neurological manifestations were reported in 56% of cases in 2025, compared with 66% in the previous decade. In general, a predominance of neurological cases is expected, because cases with more severe symptoms are more likely to be diagnosed, ECDC specialists show.
Dozens of outbreaks at equidae and birds
This year, in Europe, 16 outbreaks of West Nile infection were also reported in Equidee (horses, wild horses, mugs, etc.) and 20 outbreaks in birds. Veterinary outbreaks started on January 15, 2025 in Germany and February 16 in Italy. Focus on equida were reported by Italy (11), Greece (2), Germany (1), Hungary (1) and Spain (1). Focus on birds (common elbow – 4, common wind – 4, Cioara Neagră – 3, Golden Pescărușul – 3, Cioara Griva – 3, Găinușa de Balta – 1, rock pigeon – 1, unidentified Columbidae – 1) were reported by Italy (19) and Austria (1).
In June and July 2025, the monthly outbreak number at equidee easily exceeded the average for 10 years (2015-2024) from June and July, while the monthly number of outbreaks from birds to July 2025 decreased below the historical monthly average, with a significant decrease in July 2025. Until August 6, 2025, or 2325 From six countries, compared to 47 regions (eight countries) in the same period of 2024 and 16 regions (three countries) in 2018. All six countries that reported outbreaks and equidae this year also reported cases, reflecting the endemic activity of the West Nile virus in these territories. In three provinces in Italy, outbreaks were reported in 2025: Foggia, L’Aquila and Lecco. In addition, the outbreaks of equida were reported for the first time by Greece in Etolia-Acarnania and Kavala, and by Spain in Almería, it is mentioned on the EDCD website.
“West nile virus outbreaks in winter, when the activity of mosquitoes is minimal, should be carefully evaluated, as it raises questions about the moment of infection. Two such reports – an outbreak of equida reported by Germany in January and one in birds reported by Italy in February – justifies a prudent interpretation, as they can reflect residual detection (for example, persistent antibodies or infections acquired in the previous year), rather than an active transmission in 2025. West Nile, as well as outbreaks at equidae and birds. On August 6, 2025, Italy represented 83% of all reported human cases and all outbreaks related to equidae and birds, emphasizing the significant activity of the West Nile virus. This is probably due to favorable climatic conditions and hot ecological points (for example, wetlands, agricultural areas) that support the transmission of the virus by influencing the populations of mosquitoes and the host’s dynamics ”ECDC shows.
The fact that in Italy the circulation of the virus is intensively supervised in Italy can contribute to high rates of detection of human cases and outbreaks to birds and equidae, ECDC stresses. On the other hand, the identification of cases of infection in humans and animals in anteriorly unaffected areas emphasizes the continuous geographical expansion of the virus, which is most likely due to environmental, climatic and ecological changes. In addition, an increased monitoring surveillance or sensitivity and increased awareness in these areas could play a role in detecting cases, the European institution shows.
The actual number of cases is most likely, much higher, ECDC appreciates, but most West Nile infections are asymptomatic or subclinical. The small reported number is also explained by the fact that seasonal supervision in humans focuses mainly on identifying confirmed cases in the laboratory, which contributes to the delay of diagnosis, specialists notes.
“Given the favorable weather conditions for WNV transmission to Europe, we expect the number of cases to humans and outbreaks in equidae and birds to continue to increase in the coming weeks. In previous years, the peak of transmission was observed in August-September. Both ECDC and EFSA will closely follow the situation in Europe, especially in terms of severity indicators ”, conclude ECDC.
How to transmit West Nile (WNV) virus
The West Nile virus is mainly transmitted by the sting of infected mosquitoes and less rarely in other ways. Mosquitoes are infected when feeding on the blood of virus -carrying birds and then when they sting people or other manifestations can transmit the virus.
People and horses are considered terminal hosts, because the virus is no longer transmitted from them.
Although rarer, there are other ways of transmission. Blood transfusions can be such a path, which is why during periods with active transmission there are screening tests in donors and areas from which donors cannot be accepted (areas with confirmed cases of infection). Another rare way of transmission is that from mother to child, transplacental, during birth and extremely rare by breastfeeding. The virus is not transmitted instead by ordinary contact between humans, nor by water consumption or food.
What are the symptoms of WNV infection
Most of the people infected with West Nile (80%) have no symptoms. The mild form can occur in 20% of infected people, symptoms-fever, headaches, muscle and joint pain, marked fatigue, rash (especially on the trunk and limbs)-manifesting 2-14 days after the infected mosquito. Usually the evolution is favorable and the symptoms disappear in a few days or weeks. In less than 1% of the infected, that is, very rarely, severe forms of disease (more commonly in the elderly and in people with low immunity). The disease can take the form of meningitis, encephalitis or myelitis and require immediate hospitalization, and can be lethal.
This severe form manifests itself with high fever, intense neck pain, stubborn neck, confusion, disorientation, speech or vision disorders, convulsions, paralysis or muscle weakness.
