A Spanish sewer worker developed a roundworm infection so bad that doctors could see the larvae crawling right under his skin.

The New England Journal of Medicine recently published the unusual case of a 64-year-old sewer treatment employee from Spain who realized that something was wrong with him after experiencing mild diarrhea and itching all over his body. He reported to the University Hospital in Madrid where doctors diagnosed him with a parasitic roundworm infection that had become unusually serious. Strongyloides stercoralis infection is usually asymptomatic, but in this particular case, it had become so serious that doctors could see the worms crawling under the man’s skin.

In photos posted in the online medical journal, doctors drew outlines around the red squiggles on the man’s body, which helped them determine that the roundworms under his skin were moving over a 24-hour period. Doctors believe that the man’s profession facilitated the infection with the roundworm that usually lives in tropical and subtropical regions around the world and that he may have been asymptomatic.

People infected with roundworms can spend years without any symptoms, but in this particular case, the patient had been administered hormone therapy for malignant spinal cord compression, which suppressed his immune system, allowing the parasite to proliferate. The hyperinfection got so bad that larvae could be seen crawling under the patient’s skin, like something out of a horror movie.

Photo: New England Journal of Medicine

The abnormal abundance of larvae in the body makes this sort of hyperinfection potentially deadly, as it can trigger sepsis and organ failure. Luckily, in this case, doctors were able to save the sewer worker’s life with strong anti-parasitic drugs.

“After treatment with oral Ivermectin, the patient’s rash and diarrhea subsided,” a hospital spokesperson said.