NEW YORK — The swine flu virus continues spreading in New York City — closing more schools and showing up in a jail — while the disease also reached farther into Asia among travelers returning from the United States.

An assistant school principal in New York remained hospitalized in critical condition yesterday and an inmate who entered the city's jail complex on Rikers Island about a month ago was diagnosed with swine flu on Friday.

The city Department of Correction said that the flu hadn't spread to other prisoners in the 13,200-inmate system.

The Rikers Island inmate — whose name or reason for being in custody wasn't released — was improving since his hospitalization Wednesday and wasn't in serious condition, Correction Department spokesman Stephen Morello said.

Morello said the inmate came into contact with about 70 other prisoners in two housing units at the center, and all had been examined and none came down with the flu.

The jail canceled weekend visits for those inmates and advised any other inmates' family members who were feeling ill not to come, he said. Surgical masks were passed out to those inmates and officers on the two housing units; hand sanitizer was given to everyone in the jails, he said.

The Centers for Disease Control and Prevention says more than 4,700 confirmed and probable cases have been reported in 46 U.S. states plus the District of Columbia. Five people have died in the United States, all with underlying ailments.

Internationally, Malaysia, India and Turkey have reported their first cases, all involving people who had traveled from the United States. They are in addition to the 36 other countries where the World Health Organization says more than 8,000 cases have been confirmed.

In Turkey, health officials said the virus was detected in a man and his mother who had traveled to Istanbul from the U.S. The Health Ministry said the two had arrived Thursday in Istanbul via Amsterdam and were traveling to Iraq.

Thermal cameras at the Istanbul airport detected a high fever in the man and he was put under observation at Istanbul's Haseki hospital along with five other family members.

A lab later detected the H1N1 virus, the formal name for swine flu, in the man and his mother. Four other family members did not have the virus, the ministry said.

Japan yesterday confirmed its first case of swine flu caught within the country, showing that the effort to block the flu at the island nation's borders had failed.

The government ordered schools closed in parts of the port city of Kobe, where the Ministry of Health said a male high school student who had not recently traveled abroad tested positive for the virus. Two students at the same school were suspected of having the virus.

The latest confirmed case is Japan's fifth overall. The first four — three high school students and a teacher — had recently returned from a school trip to Canada.

Mexico said tests have confirmed two more deaths from swine flu, bringing the nation's toll to 68. Health officials say tests confirmed 207 more cases for a total of 3,102, including the deaths.