NAGANO, Feb. 18 — In an Olympic Games plagued for a week by bad weather, the latest enemy is a vicious flu that has swept through Japan and landed squarely in the lungs of dozens of athletes, officials and journalists in Nagano.

Nearly 900,000 people have taken ill and at least four children have died in Japan this winter in one of the worst influenza outbreaks in years. At least 20 people, including 17 schoolchildren and three elderly people, have died from complications of flu. About 900 schools have shut down to stem the virus's spread, and more than 15,000 more have canceled some classes. Prime Minister Ryutaro Hashimoto's wife, Kumiko, was hospitalized recently with the virus.

In Nagano, it seems as if everyone is coughing on the crowded shuttle buses that carry people from one venue to the next. Chatter about snow and fog and rain has been replaced by more serious talk about antibiotics and pneumonia. Most news organizations and athletic delegations have had at least one person a day in bed with high fever, respiratory ailments and other flu symptoms.

American figure skater Tara Lipinski, who is favored to win a medal after placing second in the first day of competition today, said she was considering moving out of the athletes' village into a hotel because so many athletes are ill. American Michelle Kwan, the odds-on favorite to win a figure skating gold medal, has been at a hotel since she arrived here last week.

Several gold medal hopefuls were too ill to compete in events for which they had trained for years. Germany's top-ranked figure skater, Tanja Szewczenko, withdrew from the Games before her event started. She had been sick with flu for more than a week and chose to return home to recuperate and prepare for the world championships next month in Minneapolis.

Canadian pairs figure skaters Marie-Claude Savard-Gagnon and Luc Bradet both came down with flu, and Savard-Gagnon was unable to complete her skating routine. The Canadian national champions finished 16th.

Norwegian speedskater Aadne Sondral, who won the gold medal in the 1,500-meter race, had to withdraw from the 1,000 meters because of flu, costing him a chance at another medal.

Canadian figure skater Elvis Stojko blamed a "brutal flu" and a groin pull for his failure to win the gold. He took the silver, instead. And many other athletes have come down with fevers that have kept them out of competition or hindered their performances.

Hiroshi Okudera, medical care director for the Olympics, said 70 people have been treated for cold or flu symptoms at Olympic clinics. He said the vast majority had simple coughs and colds, but two or three were referred to local hospitals for further treatment.

Okudera said there is no accurate count of how many athletes have been sick because many have sought treatment from their national delegation's doctors. He said delegations were reluctant to release information on how many of their athletes are sick.

Okudera also said he believed some athletes were simply using flu as an excuse for their poor performances. "We'll never get a correct answer," he said.

American athletes have remained fairly healthy, according to spokeswoman Sue Snouse. "Two coaches have had the flu, but the rest of our illnesses have been common upper respiratory infections," she said.

Some of the worst-hit people in Nagano have been the 8,000 journalists covering the Games. Most of the journalists work together in the Main Press Center, a huge convention hall, and live in apartment complexes constructed for the Games. They travel back and forth on crowded shuttle buses, which seem to be perfect flu incubators.

Tonight, many of those reporters went to Nagano's White Ring arena to watch women's figure skating, where the first skater of the night, Maria Butyrskaya of Russia, skated to the most appropriate music of the day: "Fever."