Tyler Butterfield has been ruled out of the Tokyo Marathon after organisers restricted the event to elite runners and wheelchair athletes because of new cases of the coronavirus in Japan.

The professional triathlete had planned to make his first appearance of the new year at the March 1 event competing in the semi-elite division.

“Tokyo Marathon has been cancelled for general entry and semi-elite, which I was in, because of coronavirus,” Butterfield said. “My guess is with 40,000 people plus spectators it was too high a risk of spreading the virus.”

An estimated 38,000 runners had been expected to participate in the annual event, one of the largest marathons in the world.

However, after a case of the viral respiratory disease was confirmed in Tokyo last week, organisers said they could not “continue to launch the event within the scale we originally anticipated”, thus reducing the field to around 200 participants.

“It’s a tough call and such a great race, but health should always come first,” Butterfield added. “Personally, I was already undecided because of it, so it made the decision for me.”

The coronavirus emerged in the Chinese city of Wuhan in December. The virus has killed more than 1,700 people in China and infected more than 75,000 people worldwide.

The organisers mulled several options, including allowing a smaller number of general-entry runners, but after going “back and forth two or three times” were ultimately swayed by the increasing number of infection cases.

Japan had its first coronavirus death on Thursday and as of Monday 520 people had been confirmed in the country as infected, including 454 who had been quarantined on a cruise ship.

Last month, Tokyo Marathon organisers set up a panel of medical professionals and specialists to assess the race’s response to the coronavirus crisis and there were preventive safety measures, including the distribution of antibacterial wet wipes and surgical masks, announced.

The Tokyo Marathon doubles as a qualifier for the Olympic Games, and runners will be chasing the final spot on the United States men’s Olympic marathon team.

The elite full marathon field includes 176 runners and 30 wheelchair athletes.

With the Olympic Games less than six months away, Games officials have voiced concerns about how the virus could disrupt the event to be held from July 24 to August 9.

The chaos caused by the coronavirus outbreak has already resulted in a host of sporting events being cancelled or rescheduled in China and Japan, but 2020 Games head Yoshiro Mori said last week cancelling the Olympics “has not been considered”.