Tens of thousands who planned to run the Tokyo Marathon won't be doing it this year. Fears of spreading the novel coronavirus as runners travel from all around the globe have prompted race organizers to slash the field from 38,000 to just over 150 elite runners.

One Boston marathoner who planned to run across the finish line at the Tokyo Marathon come March 1 had her dreams dashed Monday when organizers announced that only elite runners and wheelchair athletes would be allowed to participate due to fears over the novel coronavirus. Liz Sweeting, 39, of Wellesley, began training for the race in December and hoped to be among the 38,000 initially registered to run the 26 miles.

Now, due to the committee´s decision, only 126 runners and another 30 wheelchair athletes will be able to participate.

"Tokyo is flat. Friends who have done it say it's an amazing race. There's lots of spectators. The energy's really great," said Sweeting. "You run by temples and just see beautiful scenery."

She told WGBH News that she had run six marathons before her planned trip to Japan.

Sweeting found out that she'd been nixed from the race while touring Europe.

"I was in a castle, just being a tourist, and one of my friends messaged me and said, 'Hey, did you hear about the Tokyo Marathon? It looks like you're not in it,'" she recalled, adding she was not completely surprised. "The week before I had seen a blog post that said the organizers of the marathon were considering cutting it back, but it hadn't been decided yet.

"I'm not personally worried about getting sick. It's better for the public's health I think, but it's still very disappointing.”

Nonetheless, she said she did have concerns about her family traveling to Japan.

"My parents were planning to come with me and they're in their seventies," Sweeting said. "They're pretty healthy as well, but I wouldn't want them to get sick either."

Sweeting signed up for the Tokyo Marathon because she hoped to be awarded the World Marathon Majors Medal. Recipients must complete marathon races in Boston, New York, Chicago, Berlin, London and Tokyo. She already crossed the New York, Chicago and London marathons off the list.

"I'm planning to run Boston this year, and had hoped to complete Berlin next year and collect the Majors Medal," she said. "The good news is that all registered runners in the Tokyo Marathon will be allowed to defer their entry until next year."

Sweeting said her attention is now focused on Boston.

"I just really love the community. It's an individual sport but I've made so many wonderful friends," she said. "I love setting goals for myself and thinking like I can't do this or I don't know if I can do this, and then achieving the goal. I love training for a marathon. It gives me a purpose. I love feeling myself getting stronger throughout the weeks and months."

Boston Marathon organizers said they are closing monitoring the covid-19 epidemic and will adhere to any directives from the federal government.

Correction: An earlier version of this story incorrectly identified Liz Sweeting's last name. We regret the error.