Jacques Dutrisac, 59, has spent more than two decades living with some nagging questions about his childhood neighbourhood in east Ottawa.

Multiple sclerosis robbed him of the use of his arms and legs years ago. He can no longer use a computer, write or even read, but his curiosity is still very much intact.

Dutrisac wants to know why 14 former neighbours — all about the same age, all from the small suburban enclave of Elmvale Acres — were also diagnosed with MS as adults.

"It's amazing, the coincidence. It's alarming, you know. It makes you really, really wonder what was here at that time," said Dutrisac, sitting in a wheelchair outside his childhood home on Plesser Street, near Canterbury Park.

'Mind-boggling'

Dutrisac said three of his childhood playmates from Plesser Street were later diagnosed with MS, including Diane Ladouceur. Dutrisac first heard about Ladouceur's diagnosis about a month after his own in 1991.

"And then a few weeks later, I found out that one of our neighbours … who was a few years younger than us, well she was diagnosed with MS. So I'm saying, 'This is kind of strange,'" said Dutrisac.

It's shocking to discover … [Three of us] were all on the same side of the street, two houses away from each other. - Diane Ladouceur

"And then, on the parallel street right behind us on Saunderson [Drive], another one, our age, we went to elementary school with her … well she's got MS … Wow. So I went, 'This is getting ridiculous, this is starting to add up.' Then it doesn't stop there."

"It's mind-boggling," said Ladouceur, now 60, who has kept in touch with some of the others from the group since her own diagnosis.

"It's shocking to discover … [Three of us] were all on the same side of the street, two houses away from each other," she said.

Diane Ladouceur, a childhood friend of Jacques Dutrisac, was also diagnosed with MS. (CBC)

List grew to 14

Over the next decade, Dutrisac found a total of 13 former neighbours who had been diagnosed with MS, all from within a 500-metre radius. A 14th person grew up on Coronation Avenue, closer to Industrial Avenue, about three kilometres away.

"It's just the strangeness, the closeness," he said. "When I could still write, I had decided, this is too much ... so I had started writing all of the names of the people."

Three on Dutrisac's list grew up on Harding Road, while others lived on Saunderson Drive, Haig Drive and Carnegie Street, all nearby.

CBC News has spoken with six of the 14 people on Dutrisac's list. One other from the group died more than 10 years ago, and Dutrisac and Ladouceur have lost touch with some of the others since they first heard about their diagnoses in the 1990s.

Ladouceur said at least seven of the 14 graduated from Charlebois High School — now St. Patrick's High School — in the mid-1970s.

"You start to question, what could it be? Is it the environment?" said Ladouceur.

Coincidence, not cluster, group told

Elmvale Acres was a new suburb when Dutrisac, Ladouceur and the others lived there in the 1960s and '70s, so far from the city core that there were cows in the fields where he and his friends used to play, Dutrisac said.

Plesser Street in Ottawa's Elmvale Acres neighbourhood, where four of the 14 MS patients on Jacques Dutrisac's list grew up. (CBC) While Dutrisac and Ladouceur have questioned whether there might be some common environmental cause, they have no proof, and there's no scientific evidence to back up their suspicion.

Dutrisac and Ladouceur said they have asked their doctors about it, but have been told the 14 cases are likely a coincidence.

"It was always minimized … they seemed to downplay it … And that bothered me, because you always want an answer … Why could this be?" Ladouceur asked. ​

Highest MS rate in world

Canada has the highest rate of MS in the world, with an estimated 100,000 people living with the disease, according to the MS Society of Canada.

Dutrisac wonders if the group from Elmvale Acres may be what the U.S.-based National Multiple Sclerosis Society calls an "MS cluster."

According to the U.S. society, a cluster is "a very high number of cases" that occur either at a "specific time," or in a "certain area."

Reports of MS clusters do come up periodically around the world, but they are very difficult to prove and usually turn out to be coincidence, according to Dr. Ruth Ann Marrie, an epidemiologist and the director of the MS Clinic at the University of Manitoba.

"It's often very challenging to confirm whether a group of cases really is a true cluster," said Marrie.

Dr. Ruth Ann Marrie, director of the MS Clinic at the University of Manitoba, says disease clusters are challenging to verify. (CBC)

In order to determine whether a cluster exists, researchers would need to know how many people living in that area could reasonably be expected to develop MS, a number known as "the background risk," she said.

"Unless you have a really accurate understanding of what those background risks are, you can't really evaluate whether this particular group is more than you would expect just due to chance alone," said Marrie.

That type of data currently isn't available for many parts of Canada, but Marrie said efforts are underway to improve how Canadian MS patients are tracked.

The Public Health Agency of Canada recently expanded its chronic disease surveillance system to include MS, in an effort to "provide an overall picture of the number of MS cases in Canada, allowing us to look at trends over time at the provincial and national levels," according to a statement from the agency.

'There's got to be something here'

Even though apparent clusters are often dismissed as coincidence, Marrie said she thinks they're still worth pursuing because of possible clues, such as genetic risk factors, that might be revealed by studying specific groups of people.

Dutrisac and Ladouceur said they're encouraged by this, and they're hoping someone might finally take them up on their offer to research the group from Elmvale Acres.

It's got to be more than a coincidence. There's got to be something here. - Jacques Dutrisac

"We were just kids in a brand new neighbourhood," Dutrisac said. "It's got to be more than a coincidence. There's got to be something here."

Ladouceur would like to see all the surviving members of the group of 14 get together.

"It would be interesting one day to just get together and chat about everything, to compare notes … and maybe we could learn something from each other," she said.