Health authorities in Italy have reported an increase in West Nile virus cases as warmer, wetter conditions extend the breeding season for the mosquitoes that carry the disease, mirroring a broader trend across southern and central Europe linking longer, hotter summers to the northward creep of vector-borne illnesses.

West Nile virus is typically mild or asymptomatic in most people, but it can cause severe neurological illness in a small share of cases, particularly among older adults and those with weakened immune systems. Italian regional health authorities have stepped up mosquito-control efforts and public advisories in affected areas.

Public health researchers say the episode is consistent with projections that a warming climate will expand the range and season of disease-carrying insects across Europe, straining surveillance systems built for a cooler climate.