Although cases of West Nile Virus have more than doubled over the past three years, the control measures put in place have ensured the safety of transfusions and transplantations, with no instances of donor-to-recipient transmission being recorded.
The data were presented during the conference on the epidemiological surveillance of arboviral diseases in Italy, held on 18 June at the Pocchiari Hall of the Italian National Institute of Health (ISS) and organised by the National Blood Centre and the National Transplant Centre.
The event provided an important opportunity for dialogue among all stakeholders involved in the system, with the aim of strengthening preparedness and response measures against endemic and epidemic arboviral diseases in Italy, following the launch of the new season of surveillance and preventive measures for vector-borne infections in the fields of transfusion and transplantation medicine, which officially commenced on 1 June.
The conference was held within the context of a national epidemiological situation marked by a rising number of infections in recent years. In 2025, the spread of West Nile virus reached an unprecedented geographical scale, involving almost all regions of Italy.
Over the last three years, data from the ISS integrated surveillance system have highlighted a substantial rise in infections. The number of confirmed cases increased from 332 in 2023 to 460 in 2024, reaching 773 in 2025, corresponding to a 133% increase over the three-year period.
Of the 773 infections reported in 2025, clinical presentations varied considerably. A total of 367 neuroinvasive cases were recorded across several regions, with the highest numbers reported in Lazio (87), Campania (83) and Lombardy (56). In addition, 339 cases of West Nile fever were notified, including three imported cases acquired in Kenya, Egypt and the Maldives, respectively.
Despite the progressive rise in infections, the preventive screening system ensured the full safety of donated blood, organs, tissues and cells for recipients. In 2025 alone, the effectiveness of these measures allowed for the prompt detection of 56 asymptomatic blood donors and two asymptomatic organ donors who tested positive for infection, thus preserving both the continuity of donation programmes and the safety of transfusion and transplantation practices.
In parallel, imported viruses such as dengue and chikungunya have been responsible for recent and significant autochthonous outbreaks across the national territory. In this epidemiological context as well, the safety of the supply chain has been maintained through targeted screening of donations: to date, no donors have tested positive.
To keep stakeholders updated on the evolving situation, the National Blood Centre and the National Transplant Centre regularly publish dedicated circulars on their websites regarding surveillance and the measures to be implemented in areas reporting cases of arboviral infections, both in humans and animals (National Blood Centre website; National Transplant Centre portal).