The soldier, whose name and rank have not been disclosed, defected to South Korea last Monday by driving a military jeep near a line that divides the Koreas and then rushing across it under a barrage of bullets.
Hospital officials said yesterday that it was too early to tell whether he will make a recovery.
While treating the wounds, surgeons found the large parasites, which may be reflective of poor nutrition and health in North Korea's military, the hospital said.
"I spent more than 20 years of experience as a surgeon, but I have not found parasites this big in the intestines of South Koreans," Lee Cook-jong, who leads the soldier's medical team, told reporters last week.
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Lee is a famous trauma specialist who was hailed as a hero in 2011 after conducting life-saving surgeries on the captain of a South Korean freighter ship who was shot during a rescue mission after being held by Somali pirates.
While the North Korean soldier's vital signs were stabilising on Saturday, he continued to remain unconscious and relying on a breathing machine. After consecutive surgeries to repair internal organ damage and other injuries, no further surgeries are planned as of yet, said Shin Mi- jeong, an official at the Ajou University Medical Centre near Seoul.
A United Nations Command helicopter later transported him to the Ajou hospital.
It remains unclear whether the North Koreans chasing the soldier fired at him even after he crossed into the southern side of the border, which would be a violation of an armistice agreement that ended the 1950-53 Korean War.
The Joint Security Area is jointly overseen by the American-led UN Command and by North Korea, with South Korean and North Korean border guards facing each other only meters (feet) apart. It is located inside the 4-km-wide Demilitarised Zone, which forms the de facto border between the Koreas since the Korean War.