This assumption is based on the 14-day incubation period of the virus and the fact that the man became symptomatic after less than a week in Hawaii, state health officials said.
The patient and his wife visited the island of Maui from January 28 to February 3, then went to Oahu, where they stayed until February 7 to return home in Aichi Prefecture, in the center of Japan, officials said.
The man showed no signs of illness before reaching Oahu, where he first developed cold-like respiratory symptoms but no fever, state health official told reporters Dr. Bruce Anderson.
When he returned to Japan, he fell seriously ill and was tested for coronavirus after going to hospital, said Anderson.
On Friday, Hawaiian authorities were informed by the United States Centers for Disease Control and Prevention (CDC), and state authorities in turn alerted local health care providers to the search for type 1 diseases. coronaviruses.
"We think this is a serious concern, and I want to assure you that this scenario is exactly what we are preparing for and are preparing for," said the governor.
The biggest immediate goal is to identify and locate people who have had "prolonged face-to-face contact" with the Japanese man after he started showing symptoms in Oahu, said Dr. Sarah Park, the Chief State Epidemiologist.
From what is known about the transmission of the disease, it was unlikely that the patient was contagious during his stay in Maui, since he was asymptomatic, and anyone who had casual and ephemeral contact with him after his illness, like spending it in a hallway, would be considered low risk, said Park.
The apparent absence of human fever in Hawaii is also a good omen, as infected people are most contagious when they are feverish, she said.
The man's precise travel itinerary remained unclear, except that he stayed in a Hilton Grand Vacations condominium in the Waikiki section of Honolulu, said Anderson, adding that he had only sought care on his return to Japan.
State health officials said they were consulting Japanese authorities for more details about his visit to Hawaii.
Hawaii, the US Pacific island state closest to the source of the coronavirus epidemic, has seen no documented infections on its soil, while the number of confirmed cases in the United States is 15 , no mortals. Eight cases are in California.
The global total now exceeds 66,000 cases, with more than 1,500 deaths, most of them in the Chinese province of Hubei, the epicenter of the epidemic.
Beyond China, nearly 450 cases have been recorded in some 24 countries and territories, and three deaths. Japan is among the most difficult nations, with 251 confirmed cases, most of them on a cruise liner quarantined in a port.
Japan confirmed on Thursday its first death from coronavirus.
Steve Gorman reports in Los Angeles; Editing by Robert Birsel