As Japan's sports world continues to battle with the coronavirus outbreak, experts are starting to question the likelihood of the Tokyo Olympics being held under normal conditions when the games kick off in less than 150 days.

The pneumonia-causing virus has prompted Nippon Professional Baseball to delay the start of its season, the J-League to extend its suspension of soccer matches, and the 15-day Spring Grand Sumo Tournament in Osaka to be held without spectators -- an option that is appearing more feasible than outright cancellation of the games given the economic stakes.

In a report released last Friday, SMBC Nikko Securities Inc. estimated that cancellation of the Tokyo Olympics would reduce Japan's annual gross domestic product growth by 1.4 percent.

The country's economy is already weakening from a plunge in tourism, dampened domestic consumption, and cancellation of large-scale sports and cultural events nationwide throughout March.

(Photo taken Feb. 29, 2020, shows a preseason game between the Lotte Marines and the Rakuten Eagles at Zozo Marine Stadium in Chiba, east of Tokyo, being held behind closed doors.)

The International Olympic Committee and Tokyo Games organizers remain adamant that the July 24 to Aug. 9 Olympics will be held as scheduled in the Japanese capital.

Japan's Chief Cabinet Secretary Yoshihide Suga reiterated the government's position Thursday after the World Health Organization declared COVID-19 a pandemic.

But the enduring threat of the sudden viral outbreak has some predicting the games could be held behind closed doors.

"There is no canceling an investment of 3 trillion yen (about $28 billion). What can be considered is holding the games without spectators," said Munehiko Harada, a professor at Waseda University's Faculty of Faculty of Sport Sciences.

Harada speculated that the scale of the games might be reduced, though, if organizers resolved to remove contact sports like judo and wrestling from this summer's program to reduce the risk of infection.

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Last month, a senior member of the IOC unofficially said that the games' governing body could wait until as late as the end of May to decide on whether to cancel or otherwise modify the games.

But Hideomi Nakahara, a visiting professor Yamano College of Aesthetics specializing in infectious diseases, said the outbreak likely will not be subdued by that time.

"Even if things are resolved by then in Japan, it won't be enough,"

he said. "The crisis has to be contained by May or June worldwide, otherwise it will difficult to hold the games (as planned)."

Nakamura also believes that the varying degree of infection from region to region could lead to some athletes abstaining from the games, as happened at the 2016 Rio de Janeiro Olympics due to fears over the Zika virus.

"If participation is allowed from countries where the virus is prevalent, there will be withdrawals from competition," Nakamura said.

Unlike COVID-19, however, the mosquito-transmitted Zika virus posed little threat to athletes and spectators at the Rio Games since the virus had spread outside of Africa several years earlier, and adequate treatment was widely available.

(People watch the Tokyo Olympics torch relay in Olympia, Greece, on March 12, 2020.)

"The situation is completely different this time as infections are now spreading rapidly across the world," said Hitoshi Oshitani, a professor in the Department of Virology of Tohoku University's Graduate School of Medicine.

A Japanese government panel of experts has estimated that containment of the new coronavirus could take months or even last beyond the year if the virus survives warmer weather.

The Olympic flame was ominously lit without spectators present Thursday in ancient Olympia as the number of coronavirus infections surged in western Greece.

Greece's Olympic Committee opted for a scaled-back version of flame lighting and handover ceremonies to remain on schedule, and Tokyo organizers said they will do the same, as required, for celebrations during the Japan leg of the torch relay.

The pandemic continues to derail the games' preparations, as an increasing number of Olympic qualifiers and test events are postponed or canceled. Recent examples include the cancellation of an Asian wrestling qualifier in Kyrgyzstan and an Asian rugby sevens test tournament in Tokyo, as well as the delaying of a 3x3 basketball qualifier in India.

And while Japan struggles to curb the spread of the virus, some of its Olympic team members are electing to stay abroad during the final stretch of Olympic preparations rather than return home and risk infection.

(Japanese athletes march at National Stadium during the Tokyo Olympics opening ceremony on Oct. 10, 1964.)

The entire Japanese badminton squad aims to keep training in Britain after the All England Open ends on Sunday before heading to the India Open at the end of the month.

The last badminton Olympic qualifier, the Asia Championships scheduled in late April, was moved last week from Wuhan, China -- where the virus originated -- to Manila.

Several Olympic host towns are also feeling the impact of the virus ahead of the games. Mongolia's archery team abandoned an Olympic training camp scheduled late last month in Okazaki in Aichi Prefecture, while Colombia's table tennis and gymnastics teams canceled camps in Kitakyushu in Fukuoka Prefecture.

"It's unfortunate it was canceled, but it can't be helped when we consider the health of athletes," a Kitakyushu city official said. "Hopefully, the crisis gets resolved soon, and we can be fully prepared for the pre-Olympic camps in July."

Kitakyushu, one of nearly 500 host towns across Japan welcoming international athletes from 167 countries and regions for camps and cultural exchanges, is planning to hold 10 camps in July, including swimming and trampoline.