ANTIBES — Let's set the record straight. A marine bacterium nicknamed the 'flesh-eating' bug — Vibrio vulnificus — has been dominating summer headlines. As seas warm up, it's spreading northward and showing up on coastlines that were previously unaffected. The European Centre for Disease Prevention and Control (ECDC) has warned of an 'increased risk of Vibrio infections throughout the summer season', especially during heatwaves, and is launching dedicated European vibriosis surveillance in 2026. The Baltic Sea — warm and low-salinity in summer — offers the most favourable conditions.
The numbers back up the trend. Denmark records around 200 serious cases during its hottest summers; in the US, infections along the East Coast multiplied eightfold between 1988 and 2018. In southern Spain, a study covering 2010–2023 logged 167 cases, rising from 4 in 2010 to 17 in 2023, with the number of days 'favourable' to the bacterium climbing to as many as 40 per year and a clear correlation with water temperature. The Mediterranean is warming 20% faster than the global ocean average: its high salinity long kept the most dangerous strains at bay, but that buffer is shrinking. In severe cases, the infection remains fatal in 20–50% of cases.
Should you skip the swim? No. Serious infections are still rare and mostly affect people with an open wound, a liver condition, or a weakened immune system. The ECDC and CDC guidance is straightforward: don't swim with an open wound (or cover it with a waterproof dressing), rinse off after your dip, avoid raw or undercooked shellfish, and see a doctor quickly if a wound turns red or swells after sea exposure. Cold, salty Atlantic and North Sea waters keep the bacterium dormant; the real risk zones are warm lagoons and estuaries during peak heatwaves. To keep an eye on the situation in near real time, the ECDC publishes a risk map (Vibrio Map Viewer).
Sources: ECDC — ecdc.europa.eu (Vibrio Map Viewer); Euronews, 24 June 2026; Gavi/VaccinesWork; southern Spain study 2010–2023, ncbi.nlm.nih.gov. General information: if in doubt, always follow the guidance of your local health authorities. Photo: Ramon Karolan / Pexels.
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