South Korean Soldiers stand guard on the South Korean side of the military demarcation line separating North and South Korea Aug. 16, with two standing partially behind the buildings to reduce their silhouettes, should they be shot at. (U.S. Army/Spc. Jeremy Reuse_

South Korean surgeons operating on a North Korean defector who escaped across the Demilitarized Zone between the two countries under a hail of gunfire on Nov. 13 have found a parasite in the man's stomach unlike any other they had seen.

The defector, who was shot five times, remained in critical condition after hours in two rounds of surgery, according to an article in the Korea Biomedical Review published on Nov. 15.

"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," Lee Guk-jong, the physician who treated him, told the Review.

"We have also discovered a parasite never seen in Koreans before," Lee said. "It is making the situation worse and causing tremendous complications."

It's unclear whether the parasite has been seen in other parts of the world.

A professor at a medical school told the Review that North Korean defectors would often come to South Korea riddled with parasites, with one patient having more than 30 types of roundworms in her body. The problem is common among defectors, the professor said, but may not be reflective of the North Korean population.

Related: North Korean Soldier Who Defected Used A Vehicle To Escape Under Hail Of Gunfire »

But the case of this defector stands above the others — his small intestine is ruptured, contaminated with fecal matter, and infected with parasites, Lee told the Review.

"He has everything that he could have," Lee said. "It is very likely that the prognosis will be worse than other general trauma patients as he has been in a state of shock induced by heavy bleeding and we expect to deal with many complications."

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