Recent outbreaks of 'flesh-eating bacteria' worldwide

Hundreds have died in recent outbreaks of the so-called flesh-eating bacteria Vibrio vulnificus and Group A strep. In 2026 Vibrio is spreading through the Mediterranean, driven by warming seas, after silently killing for decades. Calling it "flesh-eating bacteria" is technically inaccurate, but the nickname captures what it does: destroying tissue so fast that limbs have to be amputated within hours. The popular term in fact covers several bacterial species capable of causing necrotising fasciitis, the progressive death of muscle and skin tissue. The two under closest scrutiny today are Vibrio vulnificus, which lives in the sea, and group A Streptococcus pyogenes, which spreads from person to person. Vibrio thrives in warm, brackish waters, where rivers flow into the sea, and reaches humans in two ways: when an open wound comes into contact with contaminated water, or through eating raw shellfish, especially oysters. In healthy people, infection usually causes only gastrointestinal symptoms. The trouble starts in vulnerable groups: patients with liver disease, people with weakened immune systems, diabetes or advanced age. In them, the bacterium can trigger sepsis and tissue necrosis within hours. According to the United States Centers for Disease Control and Prevention (CDC), one in five patients with a severe infection dies within a few days. Streptococcus pyogenes has a different biology. It is transmitted via the respiratory route or through wounds in the skin, not through seawater. In its most dangerous form it causes streptococcal toxic shock syndrome (STSS), with a mortality rate of around 30%. Although it has been known about for decades and responds well to antibiotics such as penicillin and amoxicillin, the number of severe cases has risen sharply in recent years. The two bacteria share the nickname, but their routes of transmission and risk profiles are different. The latest outbreaks: from Florida to Japan via the Mediterranean The recent record of Vibrio vulnificus in the United States is the best documented in the world. Since 1988, the country has recorded more than 2,600 infections and over 700 deaths linked to this bacterium. The cases are concentrated along the southern coast, especially in Florida and Louisiana, where the climate is ideal for it to proliferate. In 2024, Hurricane Helene’s landfall in September caused coastal flooding that sent infections soaring: Florida reported 82 cases and 19 deaths, record figures according to state authorities. Total deaths linked to Vibrio in Florida that year reached 89, according to the state Department of Health. The year 2025 was no better. By August, Florida had recorded 13 cases and 4 deaths, while Louisiana — where the historical average rarely exceeded one death a year — reported 17 hospitalised cases and another 4 deaths, a 400% increase in fatalities compared with previous years. The most recent case occurred on 21 July 2025, when a 77-year-old man died in Bay St. Louis, Mississippi, after becoming infected through a scratch on his leg while working with a boat trailer. In all, eight people died from this bacterium in the US in just the first months of that year. In Asia, the focus of concern has been different. In Japan, cases of streptococcal toxic shock syndrome caused by Streptococcus pyogenes reached 941 in 2023, the highest figure on record at that point. In 2024, that number was surpassed in barely six months: Japan’s National Institute of Infectious Diseases confirmed 977 infections before the halfway point of the year, with 77 recorded deaths. The country had been registering between 100 and 200 cases of this disease a year since 1992, which makes the recent figures particularly striking. Europe, for its part, is facing the problem from the marine flank. Between 2014 and 2017, the average annual number of Vibrio infections on the continent stood at 126. In 2018, an especially hot summer tripled that to 445 cases, mainly in Baltic countries: Norway, Sweden, Denmark, Finland, Poland and Estonia. In June 2026, as summer began, the European Centre for Disease Prevention and Control (ECDC) was already classifying the months ahead as a high-risk season. Spain is not starting from scratch: Galicia recorded three significant outbreaks caused by Vibrio species in the last two decades — 64 people affected in 1999, 80 in 2004 and nearly 100 in 2012 — all linked to the consumption of local shellfish. Heat as an ally: a threat that rises with the thermometer The key question is not just how many have died, but why the numbers keep going up. The answer lies, to a large extent, in water temperature. Bacteria of the Vibrio genus thrive between 20°C and 35°C in waters with moderate salinity. Those conditions, once confined to tropical and subtropical coasts, now extend every summer to latitudes that were too cold for this microorganism thirty years ago. Jan Carlo Semenza, an epidemiologist at Umeå University in Sweden, has documented this direct correlation: the higher the sea surface temperature, the more infections. The European Environment Agency calculates that sea surface temperatures in Europe have risen between four and seven times faster than the global ocean average. The Mediterranean, regarded by the scientific community as one of the regions most vulnerable to global warming, is particularly exposed. And not just because of temperature: as bodies of water shrink in size due to heat, the remaining mass concentrates bacterial density, increasing the risk of exposure. In July 2024, the European Food Safety Authority (EFSA) published a comprehensive assessment of the risks posed by these bacteria, and its conclusion was clear: their prevalence in seafood is expected to increase, both in Europe and in the rest of the world, as a consequence of climate change. This projection includes the geographical spread of the bacterium to coastal areas where it is currently barely detected. The ECDC, for its part, has developed a surveillance system based on satellite data on sea temperature and salinity, which generates real-time risk maps to guide national alerts. The impact is not only on health. Hatim Aznague, Climate Action and Energy Resilience analyst at the Union for the Mediterranean, sums it up neatly: "Bacteria are not the story; they are the messengers. The story is a sea thrown off balance by heat and pollution". A beach closed in high season means immediate financial losses for hotels, restaurants and tour operators. The Mediterranean is the most visited holiday region in the world, which amplifies the impact of any health alert. Vibrio infections have risen by more than 84% globally since the early 2000s, according to consolidated data. If the trend does not change, what is now a seasonal, localised risk could become a structural public health problem before 2050.