Thessaloniki: The West Nile virus is moving through Europe earlier and across more ground than usual this summer, according to the latest surveillance from the European Centre for Disease Prevention and Control, which now tracks local transmission in dozens of regions from the Aegean to the Rhine.

By the end of July the centre had logged mosquito-borne infections in 49 regions across seven countries. Italy carries the heaviest load, followed by Greece, with further clusters reported in Romania, North Macedonia, Spain, France and, for the first time this season, a single German region. The pattern confirms what epidemiologists have warned for years: the disease no longer belongs only to the warm south.

Greece has felt the sharpest early surge. Health authorities recorded 21 locally acquired cases by 22 July, and almost all of the patients developed serious neurological illness such as encephalitis or meningitis. That ratio worries doctors, because it suggests the milder infections, which usually outnumber severe ones many times over, are going uncounted.

The virus spreads when mosquitoes bite infected birds and then bite people. Most of those infected feel nothing, but a small share fall gravely ill, and there is no vaccine and no specific cure. Care comes down to managing symptoms, which makes prevention the only real defence.

The centre expects the numbers to climb. Europe’s transmission window runs roughly from early June to late October, and past seasons peaked in August and September. Hot, still weather of the kind now sitting over southern Europe lets mosquito populations swell and shortens the time the virus needs to multiply inside them, so the coming weeks are likely to bring the bulk of this year’s cases.

The agency works alongside the European Food Safety Authority, which tracks the same virus in horses and birds and gives veterinary early warning of where human cases may follow. That joint animal-and-human watch has become a template for the mosquito-borne threats, including dengue and chikungunya, that are creeping northward as the climate warms.

Public health officials are pressing familiar but effective advice. Local authorities are draining standing water where mosquitoes breed, spraying known hotspots and urging residents to use repellent and screens after dusk. Blood services in affected regions are also screening or deferring donations to keep the virus out of transfusions.

The centre publishes case counts every week through the season on its surveillance dashboard, and sets out prevention guidance on its disease pages. For now the message from the experts is steady rather than alarmed: the season is early and broad, and it is far from over.