PEABODY, Mass. — At 28, Dan Pimenta was at a high point in life – he had just got a permanent slot on the Fire Department and had a part-time construction job. He and his wife, Donna, had a new baby boy at home, and he was healthy.

Except he wasn’t, not by a long shot.

Pimenta started experiencing a strange numbness on the right side of his head. It spread to his arm, leg and foot.

“I didn’t know what was going on,” Pimenta recalls. “Doctors at first thought it was Lyme disease.” There was test after test … after test. Finally, an MRI revealed the real problem: multiple sclerosis. And that’s when it got scarier.

Multiple sclerosis is a chronic, often progressive, disease that affects the body’s central nervous system. It affects people differently, but can lead to severe paralysis.

Doctors told Pimenta it was the end of his career; he would probably end up in a wheelchair for the rest of his life.

“It was hard on my wife (too). We were just starting our family,” Pimenta says, recalling the stress and anxiety. He lost about 50 pounds, dropping to 160.

Then he met Dr. Andrew Leader-Cramer, a neurologist at Salem Hospital. Leader-Cramer offered a ray of hope.

Pimenta recalls him saying, “You’re 28 years old, kid. Where are they getting that? You’re going to be fine. Everyone is affected differently with this disease.” And Leader-Cramer was right.

He got Pimenta accepted into a lottery for a new drug, Betaseron, which was used for cancer patients but was just starting to be used in treating MS. Sensation returned to the right side of his body, indicating Pimenta was a good candidate for the drug.

The city’s health insurer was then willing to cover the treatment, and with a letter from his doctor, the fire chief and mayor were willing to let him return to work.

Pimenta got on a regular regimen, changed his diet (no more fried foods), exercised regularly, and never had a significant episode again.

Twenty-five years later, Pimenta, 53, is still on the front lines fighting fires in his hometown. He works on Engine 4 at the Tremont Street station, around the corner from his house. To look at him, you would never know he has a degenerative disease.

In fact, many of his fellow jakes didn’t know until recently that he had MS. When he originally got sick and was out of work for several weeks, close friends came to visit him at home and learned of the disease. When he returned to work, Pimenta largely kept that side of his life private.

“I can’t let them look at me any different, as a crutch,” he says – especially when it comes to risking life and limb on a daily basis. He gradually opened up over the years, though, he says. And today, “they don’t look at me any different.”

Initially he didn’t even tell his two children, waiting until they were 11 and 9. Pimenta said he didn’t want to worry them. “It was one less thing (as a burden) for them.”

Since that initial diagnosis, Pimenta has done numerous races and charitable events to support the National Multiple Sclerosis Society – he just did the MS Climb to the Top on March 4 (61 flights of stairs up the former Hancock Tower in Boston) – but to mark 25 years, he felt it was time to do something bigger and go public.

Members of the Fire Department are wearing custom designed T-shirts around the city’s firehouses in March for MS Awareness Month.

A dozen firefighters will also don racing jerseys as the Peabody Fire Honor Guard team to join Pimenta this year to ride 150 miles over two days in June from Quincy to Provincetown for the Bike MS: Cape Cod Getaway. This will be Pimenta’s eighth ride.

He actually doesn’t take his medication anymore. He still sees Leader-Cramer for regular visits, but over the years, they talked about the possibility of him experiencing fewer episodes as he got older.

So Pimenta resolved to back off the medication when he turned 50. He said his body slowly adjusted to the withdrawal.