Josh Nelson's own body proved to be a deadlier enemy than anything he encountered in Afghanistan or Iraq.

As the pilot of a C-130 Hercules cargo plane, Lt. Col. Nelson flew scores of wartime missions during five overseas deployments with the U.S. Air Force Reserve.

But when he returned home to Otsego, he was knocked off the flight line by a devastating and mysterious disease that cost him years of agony and, ultimately, his large intestine.

The Air Force doesn't look kindly on pilots who lack a colon; it's an automatic disqualification from flight status. Nelson was told that his days in the sky were over.

But with the help of a surgeon at M Health Fairview University of Minnesota Medical Center, Nelson became the first Air Force pilot to return to active duty after a colectomy.

Under his green flight suit is a bag that collects his body waste and, in his words, "gave me my life back."

"I didn't give up. I kept moving forward," said Nelson, who's stationed at the Air Force Reserve base at Minneapolis-St. Paul International Airport.

At 40, Nelson looks like a poster boy for the Air Force. And in a way, he might be just that.

"Hopefully, his case will be an example that people can be part of the armed services even with a stoma," said Dr. Wolfgang Gaertner, referring to the opening in Nelson's belly that allows waste to pass out of his body.

"He's an amazing human being," added Gaertner, who removed Nelson's colon in two surgeries nearly three years ago. "Any challenge you put in front of him — there are no obstacles with Josh."

Nelson grew up in Monticello and joined the reserves as a student at St. Cloud State University. Beginning as a mechanic, he went on to officer training school and qualified to pilot C-130s in 2008. He's a full-time, professional Reserve officer, serving as a flight instructor between deployments.

Nelson did his overseas tours without any problems. But when he returned from the last one, in the spring of 2017, "all the fun broke loose," he said.

Out of nowhere, he began having bowel troubles, with multiple bouts of diarrhea every day. Within months, it got so bad that he was hospitalized. Doctors told him he had ulcerative colitis, an inflammation of the intestinal tissues that affects perhaps one or two people in 10,000.

It's an autoimmune disease, meaning the body is attacking itself. And doctors don't know exactly what causes it. Gaertner's best guess is that it's a combination of genetic factors, environmental influences and infection.

"To say that we can pinpoint the cause, I would be lying if I said I knew that," Gaertner said.

Nelson's life became a living hell, at the risk of understating the case. He was "a prisoner of the bathroom," he said, with attacks of bloody diarrhea upward of eight to 10 times a day.

It's 40 miles from his home to the air base at MSP, he said, "and I know where every bathroom is." His weight dropped from 185 pounds to 150. The pain was so intense that sometimes he spent hours at home curled up in a fetal position.

When medications failed to solve his problem, Nelson decided that surgery was his best option. Gaertner removed Nelson's entire colon — more than 5 feet in all.

Taking his case to the top

Nelson didn't want to give up the fulfillment he finds in military service.

"The camaraderie, the brotherhood and sisterhood is second to none — that esprit de corps," he said. "To be part of that type of organization is truly an honor."

Nor did he want to see his years of hard work washed away.

"It takes a lot of time and dedication," Nelson said. "Not many people can say they've graduated flight school and met C-130 qualification. You work very hard to get to that level."

When Nelson decided to appeal his flight status, he found a willing partner in his surgeon.

"I said, 'Josh, if that's your goal, that's my goal, too,' " Gaertner said. "Anybody would have done what I did if they meet Josh."

It was a tall order. No Air Force pilot had ever returned to service after a colectomy or ileostomy (involving the lowest part of the small intestine), and the pair set out to educate the Air Force medical staff — right to the very top.

"We had to study G-forces and pressures, and how that would affect his [small] intestine, and the bags, and the adhesives," Gaertner said. "We searched the literature. We went on for months because they kept requesting more data."

It helped that Nelson is a cargo pilot. Unlike fighter pilots, he's not subject to extreme G-forces; he doesn't operate at high altitudes, nor does he wear a tight, pressurized flight suit.

Still, when his case finally went before the Air Force surgeon general, an outside consultant who advises the Air Force on medical issues recommended against returning Nelson to duty.

'Never give up'

In November 2019, nine months after his final surgery, Nelson's phone rang. It was his flight surgeon, delivering a message that he found hard to absorb: Nelson was being reinstated to flight duty.

"I thought he was [messing] with me," Nelson said with a laugh. "I'm pretty certain I melted in my own feet. The amount of stress I went through, and finally somebody believed in me."

Although his wife, Natalie, had been his "bedrock" through the whole ordeal, Nelson confessed that his first text with the news went to Gaertner.

"We both found it gratifying," Gaertner said. "We thought we might be doing something that will help people in the future. I felt like that gratification was far and beyond just focusing on Josh, and he felt it too."

On his first birthday after the surgeries, his daughters Brinley, 10, and Brenna, 7, gave him a shirt that reads: "No Colon, Still Rollin'."

Life for Nelson is back to normal. He has no diet restrictions and can eat whatever he wants, though he often chooses salads. "I just really focus on chewing," he said.

Nelson's conclusions about the whole experience are simple yet profound.

"Don't take your life for granted," he said. "We have no idea what's going to happen to us tomorrow.

"Number 2 is, never give up if it's something you want to do. I always told people, I would be taken out kicking and screaming."

John Reinan • 612-673-7402