Italian health authorities are warning that a warmer climate is allowing West Nile virus to spread farther and persist longer across the country. More than 650 infections have been recorded in Italy so far this year, representing roughly half of all European cases, according to the National Institute of Health (ISS).
Climate‑linked rise in mosquito activity
“Higher temperatures linked to climate change help mosquitoes reproduce and extend the transmission season, increasing the chances that infected mosquitoes will spread the virus to people,” said Antonino Bella, a researcher at the ISS. The virus, which has been endemic in Italy since 2020, now appears each summer and early fall, with warmer weather sometimes pushing the transmission window into November.
Impact on public health
About 80% of those infected show no symptoms. Most of the remainder experience a mild, flu‑like illness, while a small minority—particularly older adults and people with underlying health conditions—develop severe neurological complications.
Experts note that this year’s case numbers are broadly in line with recent seasons, but the expanding geographic reach of infections suggests a gradual spread of the virus into areas that were previously largely unaffected.
European concern
Italy’s extensive monitoring network, which tracks mosquitoes, birds, blood donors and human cases, helps explain why the country detects a high number of infections. The experience is drawing attention from northern European nations. A Belgian research team visited the ISS last May to study Italy’s surveillance system, and the Netherlands reported more than two dozen cases this year—the first since 2020—along with several deaths.
“There’s no doubt that warming weather will expand the period of replication for the virus and the vector in more countries,” said Marc‑Alain Widdowson, head of the Pandemic Threats, Communicable Diseases, and AMR Division at the World Health Organization’s Europe office. He cautioned that climate change is not the sole factor, but emphasized that longer, hotter summers give mosquitoes a larger window to survive and transmit disease.
Broader environmental factors
Widdowson also cited loss of biodiversity and changes in land use as contributors to increased activity. Declines in bird diversity may favor species that serve as efficient reservoirs for the virus, while a longer mosquito season creates more opportunities for transmission.
The European Centre for Disease Prevention and Control (ECDC) warned that a warming trend—characterized by more frequent heat waves, flooding and longer summers—creates favorable conditions for invasive mosquito species such as Aedes albopictus and Aedes aegypti. The latter, known for transmitting dengue, yellow fever, chikungunya, Zika and West Nile, has been established in Cyprus since 2022 and could spread further across Europe.
A decade ago, Aedes albopictus was present in eight European countries, affecting 114 regions. This year the mosquito is established in 13 countries and 337 regions, according to the ECDC.
What communities can do
Public‑health officials encourage residents to eliminate standing water where mosquitoes breed, use protective clothing and repellents, and seek medical attention if flu‑like symptoms develop after a mosquito bite. Ongoing surveillance and rapid reporting remain essential tools for containing the virus as Europe adapts to a changing climate.
Original reporting: Alexandria, VA News – WTOP News — read the source article.
