Fever, chills and sudden sores all over your body — it sounds like the type of fatal disease affecting mankind in an apocalyptic movie. But the illness is real when someone is infected with flesh-eating bacteria.

The condition known as necrotizing fasciitis, in which an infection rapidly kills the body's soft tissue, comes when dangerous bacteria enters the bloodstream. One of the most recent cases was in September in Ocean City, Maryland, where a man was cleaning crab pots when Vibrio vulnificus bacteria got into a cut on his leg. DelmarvaNow reported that the man, Michael Funk, fell ill within hours. “Days later, ulcerated and full of lesions, it was ‘like something out of a horror movie,' his wife, Marcia, told the newspaper. The flesh-eating bacteria was in his bloodstream.” Funk died four days after getting the cut.

Read: How Your Body Fights Off a Fungus

When one of the harmful types of bacteria — Group A Streptococcus being the most common culprit — is ingested by, for instance, eating undercooked shellfish, the worst that may happen is diarrhea and vomiting. But when those bacteria cause necrotizing fasciitis, severe pain and soreness will progress to swollen and discolored skin, ulcers and blisters, the Centers for Disease Control and Prevention says. Victims will also have a fever, chills, fatigue and vomiting. According to the CDC, “These confusing symptoms may delay a person from seeking medical attention. If you think you may have these symptoms after a wound, see a doctor right away.” Live Science adds life-threatening symptoms like crticially low blood pressure and septic shock in the later stages of the infection.

Infections of flesh-eating bacteria are rare, and are more likely to occur in people who have weakened immune systems, like those who have liver disease. But in these rare cases, the bacteria infects tissue around muscles, nerves, fat and blood vessels. The CDC says people with these infections should be treated with antibiotics immediately. Severe infections stemming from wounds may require amputation to stop the bacteria from advancing.

Prevention is the most effective defense against flesh-eating bacteria, however. Live Science notes that not eating raw or undercooked shellfish is one way to avoid a foodborne bacterial illness, and properly caring for wounds could also stop bacteria from entering your system.