The mass participation race at the Tokyo marathon, which was expected to have 38,000 people taking part, has become the latest sporting casualty of the coronavirus. In a statement organisers confirmed the event on 1 March will now be limited to the elite field of 176 athletes and 30 wheelchair athletes.

“We have been preparing for the Tokyo marathon 2020 while implementing preventive safety measures, however, now that a case of Covid‑19 [coronavirus] has been confirmed within Tokyo, we cannot continue to launch the event within the scale we originally anticipated,” they said.

Organisers said that all registered runners would be allowed to defer their entry until next year. But they would have to pay again and would also not get their money back from this year’s race. One British runner who had entered the race told the Guardian that she understood the decision but from a personal and financial perspective it was hard to take 13 days before the race.

“My husband Max and I had been planning to run the Tokyo marathon for over two years so to hear this news is gutting,” said Sarah Dudgeon, who had been hoping to run the race in under three hours.

“We understand and respect the decision but you can’t helping feeling the personal ramifications. We had trained hard through the winter and were hoping this would be the running holiday of a lifetime. As things stand, we don’t know whether the £3,000 we have paid for flights and hotels will be refunded if we decide to run the race next year.”

Last week organisers had sounded confident the event would go ahead, announcing plans to distribute surgical masks to runners and volunteers as part of preventive safety measures against the virus. They had also told the 1,800 runners from China they could defer their entry until 2021 without any penalty.

However, the continuing spread of the virus meant on Monday they had little choice but to take the drastic step of limiting the race – which doubles up as an Olympic trial for Japanese marathon runners – to just over 200 participants.

The news is bound to raise more concerns about whether the virus could disrupt the Olympic Games in Tokyo, which are due to start on 24 July. So far there have been more than 70,000 cases in China, with 1,770 deaths. Last week senior officials at the International Olympic Committee insisted there was no plan B to reschedule the Games.

“There’s no case for any contingency plans or cancelling the Games or moving the Games,” John Coates, the head of an IOC inspection team, said. He added the World Health Organisation had advised him that a back-up plan was not necessary and that the Games remain “on track”.

Other experts have warned that the coronavirus-related health risks to Japan are hard to predict. “There is no guarantee that the outbreak will come to an end before the Olympics because we have no scientific basis to be able to say that,” said Shigeru Omi, a former regional director of the WHO.

The Olympic rings are displayed in front of the Japan Olympic Museum in Tokyo. Photograph: Athit Perawongmetha/Reuters

The Tokyo marathon is the biggest sporting event to be affected by the coronavirus. In the past month the World Indoor Championships, due to take place in Nanjing, China in March, were cancelled along with the Shanghai Formula One Grand Prix.

Other sporting events to have been called off or postponed in recent months because of the virus include the Hong Kong Sevens international rugby tournament, the annual Singapore Yacht Show and almost all sports in China.

The London marathon said the situation for the race in April remained unchanged. Hugh Brasher, the event director, said: “We, along with the rest of the world, are monitoring closely the developments relating to the spread of coronavirus and noting the updates and advice given by the UK government, the World Health Organisation and other public bodies. With more than two months to go before the event on Sunday 26 April, we will continue to monitor the situation. We will keep our deferment policy under review as the situation evolves.”