A North Korean defector who was shot fleeing the country Monday is struggling to recover due to the “enormous number” of parasites in his intestines, doctors say.

“We are struggling with treatment as we found a large number of parasites in the soldier’s stomach, invading and eating into the wounded areas,” the lead surgeon, Lee Cook-jong, told a briefing of journalists Wednesday.

“In my over 20-year-long career as a surgeon, I have only seen something like this in a textbook.”

Cook-jong said the longest worm removed from the man’s intestines was 11 inches long.

The North Korean’s condition offers insight into hygiene and nutrition in the impoverished and isolated state, where human feces is widely used as a fertilizer due to a lack of a chemical alternative. Parasites can enter the body through contaminated food grown using the makeshift fertilizer, known as “night soil.”

The unnamed soldier – an army staff sergeant in his mid-20s – was left in critical condition after his former comrades opened fire as he tried to cross the border between the two countries Monday.

The defector had attempted to reach the border in a jeep, but ran once the vehicle became stuck in a ditch, and was shot in his buttocks, back, shoulder, armpit and knee.

A South Korean soldier found him collapsed in some bushes south of the Military Demarcation Line that separates the countries, and he was rushed by helicopter to a hospital in Gyeonggi Province for emergency surgery.