The man fell ill during the second week of his vacation in Hawaii. At the time, officials said, the couple was staying at a time-share in Honolulu, on the island of Oahu. Before that, the couple had been in Maui, but the man showed no symptoms while he was there. It remained unclear if the woman showed any symptoms while on vacation.

Officials said that the man began showing signs of illness on Feb. 3, and wore a mask when he went outside the time-share, the Grand Waikikian by Hilton Grand Vacations, in the Waikiki neighborhood of Honolulu. Representatives for Hilton did not respond to a message seeking more information.

Several days later, on Feb. 7, the couple returned to Nagoya, Japan’s fourth-largest city. A day later, the man visited a hospital after developing a fever, but he was not admitted, Japan’s health ministry said. He learned he had pneumonia two days later, but was again released from a hospital.

On Thursday, he was taken in an ambulance to a hospital for the third time, and Hawaii health officials learned on Friday morning that he had tested positive for the coronavirus. His wife also went to the hospital on Friday with a fever, and on Saturday, she was also confirmed to have the virus.

Dr. Sarah Park, the state epidemiologist for the Hawaii Department of Health, said that the man was most likely infected either before he came to Hawaii or while he was on his way to Hawaii in late January. He did not have symptoms of the coronavirus while he was on Maui, officials said, and he wore a mask on the plane when he returned to Japan.