Italy reports over 650 West Nile virus cases amid warming climate

Italian health authorities have documented over 650 West Nile virus infections this year, accounting for roughly half of all cases reported across Europe. This surge is occurring as warmer temperatures and extended warm seasons are observed across the continent. Antonino Bella, a researcher at Italy's National Institute of Health, stated that higher temperatures linked to climate change facilitate mosquito reproduction and prolong the transmission season, thereby increasing the likelihood of infected mosquitoes spreading the virus to humans.

West Nile virus has been considered endemic in Italy since 2020, with cases typically appearing each summer and early autumn. While most infected individuals experience no symptoms or mild flu-like illness, a small percentage develop severe neurological complications, primarily older adults and those with pre-existing health conditions. This year's case numbers are consistent with recent seasons, but warmer weather can extend the transmission period into November. Additionally, areas previously unaffected by the virus are now reporting infections, indicating a gradual spread.

The Netherlands has reported more than two dozen West Nile cases this year, along with several deaths, representing the first such occurrences since 2020. Marc-Alain Widdowson of the WHO Europe office noted that warming weather expands the replication period for both the virus and its mosquito vectors, allowing them to survive longer. He cautioned against attributing the phenomenon solely to climate change but acknowledged that a warmer climate leads to a longer mosquito season and better virus survival.

Experts also point to a warming climate, loss of biodiversity, and alterations in land use as contributing factors to the increased West Nile virus activity. A longer mosquito season provides more opportunities for transmission, and a decline in bird diversity may favour species that are efficient reservoirs for the virus. The European Centre for Disease Prevention and Control (ECDC) has warned that Europe's warming trend, characterised by more frequent and severe heatwaves and floods, creates more favourable conditions for invasive mosquito species like Aedes albopictus and Aedes aegypti.

Disagreement on virus spread

While Italian health authorities report over 650 West Nile virus infections this year, accounting for about half of Europe's cases, the digest from Unknown outlet, under the headline "With the Heat Rising, a Virus Hits Italy!", offers a more general statement that "a virus hits Italy" without specifying case numbers or the proportion of European totals.

What the coverage left out

None of the left-rated digests mention the specific detail that Italy's West Nile virus cases have been considered endemic since 2020, when cases began to surge. None of the centre-rated digests mention the specific detail that Italy's West Nile virus cases have been considered endemic since 2020, when cases began to surge. None of the right-rated digests mention the specific detail that Italy's West Nile virus cases have been considered endemic since 2020, when cases began to surge.