Hurricane Ian made landfall in Florida on 28 September as a Category Four hurricane, according to the National Weather Service. Ian deposited 20 inches of rain and caused flooding from the west coast to the Atlantic coast. The Florida Department of Law Enforcement reported 130 deaths as of 1 November.

One of the results of Hurricane Ian was a spike in Vibrio vulnificus infections. As of 4 November, the Florida Department of Health reported 66 cases of V. vulnificus and 13 deaths. This was highly concentrated in Lee County, which experienced 28 cases and six deaths. This is the highest burden of V. vulnificus infections since 2008, the oldest data reported by the Florida Department of Health. GlobalData epidemiologists predict that the consequences of Hurricane Ian, like flooding and infrastructure breakdown, will increase the risk of waterborne infection in the coming weeks and months. 

Vibrio vulnificus is a bacterium that lives in water and can grow on shellfish such as oysters. It is classified as a halophilic bacterium, meaning it requires a salty environment such as seawater. Vibrio species thrive in warm water, and the Centres for Disease Control and Prevention (CDC) report that 80% of infections are between May and October. Vibrio vulnificus exposure happens in two ways; the first is ingestion via raw shellfish, while the second is through open wounds in the skin. Events such as Hurricane Ian, which cause flooding and high exposure to brackish water, increase the likelihood of exposure.

Infection with certain Vibrio species results in a disease called vibriosis. Vibriosis caused by eating the bacterium results in abdominal pain, vomiting and diarrhoea. Skin or wound infection by V. vulnificus specifically can cause necrotising fasciitis, earning it the moniker ‘flesh-eating bacteria’. Symptoms of wound and bloodstream infection include fever, pain, swelling, discharge and low blood pressure. V. vulnificus infection can lead to amputation and ultimately has a 20% mortality rate.

Certain populations are at higher risk of serious illness from V. vulnificus, including those with liver disease, low stomach acid, cancer, diabetes or immunocompromised status. According to GlobalData epidemiologists, by the end of this year, the US will reach 22.61 million diagnosed prevalent cases of type 2 diabetes, 1.32 million diagnosed prevalent cases of HIV, and 2.20 million diagnosed prevalent cases of hepatitis C. Individuals in these high-risk groups should remain vigilant about exposure to potentially contaminated waters, especially in flood conditions.

The CDC recommends avoiding saltwater with open skin, covering wounds with waterproof bandages, and cleaning skin thoroughly after contact with seawater. Areas with heavy flooding are at increased risk of brackish water exposure, so diligence with cleanliness and access to first aid are essential for preventing infection.