Tokyo: The number of confirmed infection cases of the new coronavirus on a cruise ship quarantined off Japan has jumped by 41 to 61, the health ministry said Friday.

Of the 61, 28 are Japanese nationals, according to the ministry. The total excludes a Hong Kong man who tested positive for the virus originating in China after recently disembarking from the Diamond Princess cruise ship.

The ministry has completed virus checks on samples collected from 273 people on the ship, including those with fever or other symptoms.

Among the 10 people who left the ship for treatment after being confirmed to be infected with the virus on Wednesday, one with a chronic disease is in serious condition, according to the ministry.

The newly confirmed 41 patients are all passengers of the ship, the ministry said, adding that none of them are in serious condition.

Of the new patients, 21 are Japanese nationals, including one in her 20s, two women in their 50s, a man and two women in their 60s and seven men and six women in their 70s. The remaining two are a man and a woman in their 80s.

The 41 people will be carried to medical institutions in Tokyo, Saitama, Chiba, Kanagawa and Shizuoka prefectures on Friday.

Excluding the infected people, a total of some 3,600 passengers and crew members will not leave the ship until Feb. 19 or later.

The ministry is planning to conduct virus checks on those on the ship who are aged or have a chronic illness even if they are exhibiting no symptoms.

According to the ministry, the World Health Organization has decided not to count those infected with the virus on the ship as infected patients in Japan as they have yet to set foot on the Asian country.

"We'd like to fully analyze how the virus spread from those who made close contact with the Hong Kong man," health minister Katsunobu Kato told a news conference.

JIJI Press