Parasitic worms are having a slimy moment. In the wake of news that a 3-inch snake parasite burrowed into a woman's brain comes the horrifying report of giant intestinal worms that went wandering in a man's innards, only to cause a rare, dangerous traffic jam in his bile duct.

According to a report in the New England Journal of Medicine, doctors in Colombia extracted not one, not two, but three large intestinal worms that had crammed themselves into the normally narrow duct, causing an uncommon, dangerous condition called biliary ascariasis.

The worms in this case, Ascaris lumbricoides, are typically found in humans. In fact, A. lumbricoides is among the most common parasitic worms found in humans, estimated to infect some 807 million to 1.2 billion people worldwide, according to the Centers for Disease Control and Prevention.

Adult worms dwell in human intestines, where they spew eggs into the infected person's feces. The worm's next victim is infected from inadvertently ingesting sewage- and egg-tainted food or water. The eggs hatch in the intestines before taking a puzzling trip through the lymphatic system to the lungs. There, they're coughed up and swallowed again, ending back up in the intestines, where they mature into adults. The adults usually lie low in the intestines after that. Most of the people infected have no symptoms of their gut moochers.

Sometimes, though, the adults decide to go for a stroll. Such was the case for the unfortunate Colombian man, a 75-year-old who lived in an area with limited access to clean water. He presented to an emergency department in Bogota with a three-week history of fever, pale stools, and progressive abdominal pain. His doctors quickly noted tenderness in his upper right abdominal quadrant and jaundice. His blood work revealed telltale signs of an infection, and an ultrasound showed "tubular structures" in the common bile duct, a central conduit that collects bile from the liver and gallbladder, passes the pancreas, and drains into the small intestine.

Probing with an endoscope, the doctors visualized a worm at the point where the common bile duct joins with the pancreatic bile duct at the entrance to the small intestine. They extracted that worm—around 8-inches long—and identified it as A. lumbricoides. But they knew they weren't done. Using contrast dye, they found two more worms in the bile duct and extracted them with a balloon catheter.

After that, they prescribed the man the anti-parasitic drug albendazole and a combination antibiotic treatment to treat secondary bacterial infection. A week later, the man's symptoms had improved.