Infections with a sea-borne bacteria, Vibrio vulnificus, are on the rise in the US as ocean waters warm due to climate change.
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A new study published this week found that infections of a type of "flesh-eating bacteria" have been on the rise in the Eastern US, thanks in part to climate change.
The analysis, published Thursday in Scientific Reports, found that the number of wounds in the US infected with a bacteria called Vibrio vulnificus increased from about 10 cases per year in 1988 to about 80 cases per year in 2018.
The bacteria thrives in warm seawater, and infections tend to occur along the southern Atlantic coast. But rising sea temperatures mean that the bacteria can now live as far north as Philadelphia. The study authors predicted that, as the climate continues to warm, Vibrio infections will reach New York in about 20 to 40 years — and the number of infections each year will double.
Most Vibrio infections occur when people eat raw oysters contaminated with the bacteria, causing watery diarrhea and cramping that usually resolves within a few days.
In rare cases, the bacteria can enter through a break in the skin — even something minor as an insect bite or a recent piercing — and infect the wound. Sometimes, this can cause a flesh-eating infection known as necrotizing fasciitis. The infection spreads rapidly and can be deadly if not treated immediately, according to the Centers for Disease Control and Prevention (CDC).
Early signs of a flesh-eating infection include red, swollen skin that's hot to the touch; fever; and pain extending beyond the inflamed area, according to the CDC. As the infection progresses, blisters or black spots may appear on the skin, and symptoms such as fatigue, dizziness, and nausea set in.
A flesh-eating infection must be treated with IV antibiotics extremely quickly. If the bacteria has consumed too much tissue on a limb, for instance, blood flow to the area stops and doctors may have to amputate the limb to remove the dead tissue.
Other complications of necrotizing fasciitis include severe scarring, sepsis, shock, and organ failure. Up to 1 in 5 flesh-eating infections are deadly, and fatality rates for Vibrio infections are similar at about 18%. According to the recent study, people may die of these wound infections as quickly as 48 hours after exposure to Vibrio.
Climate change has warmed ocean waters around the world, increasing the possible reach of water-borne bacteria like Vibrio. This is not the first time researchers have noted the movement of an opportunistic pathogen related to climate change, and it won't be the last.
Naegleria fowleri, known as the brain-eating amoeba, has also spread northward as waters have gotten warmer. Unlike Vibrio, it can only survive in freshwater, so the amoeba is usually found in lakes and rivers during summer months. The associated brain infection is almost always fatal, but cases are extremely rare.
Ticks and mosquitoes — and the viruses and bacteria they carry — are also taking advantage of warmer temperatures. The peak season for insect bites has grown longer in recent years, driving a rise in rates of West Nile disease and new tick-borne illnesses across the US.
