July 30, 2025, 12:39 pm | Read time: 4 minutes
With the summer heat, the risk of infection from Vibrio bacteria also rises here—an infection can be fatal in the worst case. This is demonstrated by a recent case on the German Baltic Sea coast. TRAVELBOOK explains where you need to be cautious of Vibrio, how to recognize an infection, and how it is treated.
Summer is in full swing, and the beaches are crowded. However, with the high temperatures, the risk of Vibrio infection also increases here at the North and Baltic Seas. These are bacteria that multiply rapidly at temperatures above 68 degrees Fahrenheit and can cause severe wound infections or gastrointestinal illnesses, as the Robert Koch Institute (RKI) informs.
According to the State Office for Health and Social Affairs (LAGuS), the bacteria have claimed the first fatality of the year on the Mecklenburg-Vorpommern Baltic Sea. “A 68-year-old local resident died from the infection despite hospital treatment,” the agency reported. It is not known exactly how he became infected, but the man suffered from various chronic illnesses.
How to recognize a Vibrio infection and why you should avoid swimming even with a small injury—TRAVELBOOK provides an overview.
Where Vibrio Bacteria Lurk
According to the RKI, Vibrio bacteria “occur worldwide in both fresh and saltwater, such as in river mouths/bays, lagoons, brackish water, and also in inland lakes.” The risk of infection is particularly higher in stagnant, shallow areas that warm up quickly.
Infections have also been reported from Sweden, Finland, Denmark, Norway, the Netherlands, the Channel Islands, and the Polish coast. There are also reports of Vibrio from the U.S., Israel, Spain, Greece, Tunisia, and Turkey. The spread of Vibrio is significantly influenced by the water’s salt content, which is particularly favorable for the bacteria in the Baltic Sea, with an average of 0.8 percent.
Climate Change Increases Risk of Infection with Vibrio Bacteria
A 2023 RKI study shows that ongoing climate change has the potential to increase human health risks from waterborne infections and intoxications. It further states that non-cholera Vibrio naturally occur in seawater but can multiply significantly in shallow water at elevated temperatures.
An infection can occur, for example, when a not fully healed wound comes into contact with pathogen-contaminated seawater. This can lead to purulent inflammations that “urgently require surgical treatment.” Additionally, consuming raw or insufficiently cooked seafood and fish can lead to a gastrointestinal infection with Vibrio.
More and more Mpox cases – how travelers can protect themselves
Rabies Risk on the Rise in Bali: What Travelers Need to Know
The Disease Can Be Fatal
The RKI warns of a potential wound infection: “An early symptom is a local pain that seems disproportionately strong given the visible wound. Fever, chills, and sepsis can also occur. Surgical treatments up to limb amputation may be necessary. Severe illnesses can be fatal.”
Regarding a potential gastrointestinal illness, it states: “Gastroenteritic infections cause cramp-like abdominal pain, vomiting, nausea, and watery diarrhea. The course is usually mild overall. In severe cases, sepsis can also occur. If sepsis is not recognized and treated with antibiotics in time, it can lead to multiple organ failure and/or septic shock, which can be fatal.” Theoretically, an infection through the ears is also possible. However, successful treatment with antibiotics is possible if detected early.
Only a Few Cases Per Year in Germany
Overall, the registered cases are low, but likely underreported. From 2002 to 2019, the RKI recorded up to 20 Vibrio infections annually across Germany—almost all in the Baltic Sea. In 2024, a total of five Vibrio infections have been reported so far, according to Mecklenburg.
According to the institute, older people with pre-existing conditions such as diabetes, liver diseases, or cancer are particularly at risk, as are children for ear infections. The known cases typically occurred from June to September.
According to the RKI, the Baltic Sea will continue to be particularly affected: “An increase in infections from non-cholera Vibrio, especially in the coastal waters of the Baltic Sea, is to be expected with ongoing climate change.”