The spread of Vibrio bacteria in seawater around the world is increasing, as water temperatures rise due to climate change, according to the European Food Standards Agency.
To make matters worse, increasing resistance to antibiotics of last resort is being observed in some species of bacteria.
Experts from the German Robert Koch Institute warn that germs can be found in clean and salty water around the world, and can enter the human body through wounds, for example. In rare cases, the bacteria can cause severe and even fatal infections.
But how much should offshore holidaymakers worry?
Regarding how dangerous it is to swim in water in which Vibrio bacteria have been detected, Matthias Grundling, a doctor in an intensive care unit and director of the sepsis unit at Greifswald University Hospital, says: “There is no reason to panic.” “The probability of infection is still very low,” he added.
The Robert Koch Institute says that between 2002 and 2019, fewer than 20 cases of infection were recorded annually along the German coast, especially during the warmer summers.
On the other hand, on the East Coast of America, infection cases increased eight-fold over the two decades until 2018, bringing cases to 80 cases annually, according to a study published by the journal Nature. Swimmers appear to face a greater risk during heat waves, according to a study of hundreds of infections in Danish waters over a period of four years.
The group at highest risk includes the elderly, those who are immunocompromised and suffer from health conditions such as diabetes, or those undergoing radiation therapy to treat cancer.
“There are two conditions that must coincide, but they must not necessarily lead to infection,” explained Matthias Grundling. “First, there must be an entry point, for example an open wound. This could be a mosquito bite or a leg wound. Secondly, people are usually immunocompromised,” he added.
The Robert Koch Institute added that young and healthy adults are rarely among the cases detected in Europe, and their infection is not serious if they become infected.
Open wound
But what should swimmers keep in mind while swimming? “You can’t protect yourself while swimming,” Grundling says. “If you have an open wound and the water temperature is higher than 20 degrees, I recommend not swimming,” he added.
He explained, “This is because recording a temperature higher than this degree, in addition to moderate salt levels, causes Vibrio bacteria to multiply more.”
According to the Robert Koch Institute, these conditions are present along areas of the North Sea and Baltic Sea coasts during warm summers, and this means that there is a risk of infection with Vibrio bacteria in those areas.
“The usual signs include pain, usually in the legs,” Grundling says of signs of Vibrio infection. The Robert Koch Institute describes the pain as localized that “seems to be disproportionate to the visible wound.”
Redness develops and spreads quickly. “This is often accompanied by fever, chills, and a general feeling of fatigue,” Grundling explains. Serious cases can become fatal.
“Sometimes patients have blisters underneath the blisters and classic signs of sepsis such as rapid breathing and a rapid heartbeat,” Grundling explained. Through sepsis, also known as blood poisoning, the body damages organs and tissues as it fights infection.
Grundling explains that in this case, an ambulance must be called immediately, because this situation is life-threatening. “The longer we delay seeing patients in the clinic, the more difficult it will be to control the infection,” he added.
He pointed out that treatment must be provided to each patient individually, because antibiotics must be provided as soon as possible, and if necessary, the source of the infection must undergo surgery. The life-threatening sepsis that often accompanies Vibrio bacteria must also be treated in the intensive care unit.