Doctors in Seoul treating a North Korean soldier, who was critically injured while crossing the border on November 13, removed a 10.6-inch long parasitic worm from his digestive tract, Reuters reported.

“In my over 20 year-long career as a surgeon, I have only seen something like this in a textbook,” said lead surgeon Lee Cook-jong, while showing photos of dozens of flesh-coloured parasites removed from the wounded soldier’s digestive tract.

The parasites highlight the food shortages and poor hygiene in the isolated nation. Hundreds of North Koreans defect to the South every year, and many of them have described the lack of nutrition and poor living conditions in the North.

North Korea, which lacks chemical fertilisers, still relies on human excrement to fertilise its fields, helping parasites spread, the experts said, according to The New York Times. In 2014, the country’s leader Kim Jong Un asked farmers to use human faeces to fertilise their fields. In a study that year, South Korean doctors checked a sample of 17 women defectors from North Korea and found seven of them infected with parasitic worms, the report said.

On Monday, after his dramatic escape, the soldier was flown by helicopter to a hospital. He is believed to be an army staff sergeant in his mid-20s, the Reuters report said. North Korea has not commented on the defection.

This is the fourth defection by a North Korean soldier through the demilitarised zone in the last three years, the BBC reported.