The extreme heat affecting Europe has raised sea temperatures, causing the dangerous Vibrio bacteria to spread much earlier than usual. Health experts are urging swimmers to take precautions against the bacteria, which can be found in coastal waters and river estuaries, particularly in popular holiday destinations.
The European Centre for Disease Prevention and Control (ECDC) has produced a risk map using satellite data based on sea temperature and salinity levels.
According to the analysis, the concentration of the bacteria, which would normally increase in mid-summer, has reached elevated levels much earlier this year due to above-average seasonal temperatures.
The bacteria multiply rapidly in warm, low-salinity waters, particularly in river estuaries where freshwater mixes with seawater and along sheltered coastal areas with lower salt concentrations.
Regions at Greatest Risk
Experts note that the Mediterranean Sea and the Atlantic Ocean generally do not provide favorable conditions for the bacteria because of their high salinity. However, heavy rainfall can alter these conditions by increasing the amount of freshwater flowing into coastal areas.
At present, the highest-risk regions are the coastlines of the Baltic Sea and the North Sea, where the bacteria are able to thrive most easily.
The risk map highlights coastal areas in countries including Bulgaria, France, Germany, Romania, and Sweden. In recent days, several beaches in Spain were reportedly closed temporarily because of the threat posed by the bacteria.
People with Open Wounds or Weakened Immune Systems Should Take Extra Care
Although the risk of severe illness remains low for healthy individuals, experts stress that certain groups should exercise greater caution.
People with open wounds, cuts, recent tattoos, or surgical incisions are advised to avoid entering warm seawater without proper protection. Individuals with liver disease, diabetes, or weakened immune systems are also considered to be at higher risk of infection.
If the bacteria enter the body through an open wound, they can cause severe pain, redness, and swelling. If left untreated, the infection may progress to serious complications, including sepsis (blood poisoning).
Be Cautious with Seafood and Avoid Swallowing Seawater
The bacteria can also enter the body through the accidental ingestion of contaminated seawater, posing a particular risk to children.
In addition, experts warn that shellfish such as mussels and oysters can accumulate the bacteria. Consuming raw or undercooked seafood may lead to stomach cramps, vomiting, and diarrhea.
Holidaymakers are advised to pay close attention to local beach safety warnings. Anyone who notices sudden changes in an existing wound after swimming should seek immediate medical attention.