West Nile spike puts Alpine towns on mosquito alert

Italy is seeing a spike in West Nile virus infections at the end of August, according to The Local Italy, which has published a guide to the disease and how to protect against it as case numbers rise across the country.

The outbreak has centred on the Po Valley and northern regions, where warm, humid conditions have proven favourable to the Culex mosquitoes that carry the virus. Health authorities are urging residents and visitors to use repellent and eliminate standing water, the outlet reported.

For towns in the Alpine arc, the news is a reminder that climate change is redrawing the map of vector-borne disease. Warmer summers and milder winters are allowing mosquitoes to survive at higher altitudes and for longer seasons than in the past.

Valle d'Aosta, with its cool Alpine climate and fast-flowing rivers, has historically been considered low-risk for West Nile virus. But that assumption is being tested as temperatures at altitude rise. The region's many irrigation channels and livestock farms create pockets of standing water that could serve as breeding grounds for Culex mosquitoes, and the tourism economy brings a constant flow of visitors from affected areas.

The Local Italy's advice is straightforward: wear long sleeves at dawn and dusk, use insect repellent containing DEET, and remove any standing water around homes and businesses. For mountain towns, where windows are often left open to catch the evening breeze, the guidance to use screens and repellent may be a new habit for residents accustomed to thinking of mosquitoes as a lowland problem.

Health officials have not reported cases in Valle d'Aosta this season, but the regional monitoring network remains on alert. The virus is primarily transmitted to humans through mosquito bites, and while most infections are mild or asymptomatic, a small percentage can develop into severe neurological disease, according to The Local Italy's report.

The broader pattern is one that Alpine regions across Europe are watching closely. As temperatures climb, the altitude at which mosquitoes can survive is rising, and with it the reach of the diseases they carry. For now, the advice to travellers and residents alike is the same as it has been all summer: take precautions, and do not assume the mountains will protect you.