New Zealand's health minister said Sunday 10 students who just returned from Mexico have tested positive for influenza. He said the cases are "likely" to be swine flu.
Tony Ryall said there was "no guarantee" the students had swine flu, but that health officials were taking precautions.
At least 81 people have died from severe pneumonia caused by a flu-like illness in Mexico, according to the World Health Organization, which declared the virus a public health emergency of "pandemic potential."
Ryall said that none of the patients were seriously ill and seemed to be recovering.
Thirteen high school students from a group of 25 students and teachers — who were quarantined and tested for swine influenza upon returning to New Zealand early Saturday.
"Ten students have tested positive for Influenza A, and these results will now be sent to the World Health Organization laboratory in Melbourne to ascertain whether it is the H1N1 swine influenza."
H1N1 influenza is a subset of influenza A.
The group from New Zealand's largest high school returned to the northern city of Auckland on Saturday on a flight from Los Angeles. Thirteen students and one teacher were unwell and one student had to be hospitalized, said Auckland Regional Public Health Services director Dr. Julia Peters.
At this stage other passengers on the flight were not being sought and the next step would depend on what the tests showed, said Health Ministry spokesman Michael Flyger.
Governments across the Asia-Pacific region were stepping up surveillance for the deadly virus after Mexico closed schools, museums, libraries and theaters in a bid to contain the outbreak. About 1,000 people may have been sickened there.
Some of those who died are confirmed to have a unique version of the A/H1N1 flu virus that is a combination of bird, pig and human viruses, WHO said.
U.S. authorities said 11 people were infected with swine flu, and all recovered or are recovering and at least two were hospitalized.
"It would be prudent for health officials within countries to be alert to outbreaks of influenza-like illness or pneumonia, especially if these occur in months outside the usual peak influenza season," WHO Director-General Margaret Chan said in Geneva on Saturday.
Japan's biggest international airport stepped up health surveillance, while the Philippines said it may quarantine passengers with fevers who have been to Mexico. Health authorities in Thailand and Hong Kong said they were closely monitoring the situation.
China said anyone experiencing flu-like symptoms within two weeks of arriving in the country from swine-flu affected territories was required to report to authorities.
Australia's Department of Health and Aging urged anyone who had returned from Mexico with influenza-like symptoms since March to seek advice from their doctors.
Malaysia and other Asian nations said they were awaiting further advice from WHO.
At Tokyo's Narita airport — among the world's busiest with more than 96,000 people using it daily — officials installed a device at the arrival gate for flights from Mexico to measure the temperatures of passengers.
A Health Ministry official said the government will monitor conditions of people returning from Mexico with their consent.
Agriculture Minister Shigeru Ishiba appeared on TV to calm consumers, saying it was safe to eat pork.
"Whether it's domestic or imported pork, pork is sanitized when being shipped" to supermarkets, Ishiba told TV Asahi. "It's perfectly safe to eat pork."
Asia has grappled in recent years with the H5N1 bird flu virus, which has killed at least 257 people worldwide since late 2003, according to WHO. Nearly 45 percent of the global bird flu deaths have occurred in Indonesia, with 115 fatalities.
Scientists have warned for years about the potential for a pandemic caused by viruses that mix genetic material from humans and animals.
No vaccine specifically protects against swine flu, and it is unclear how much protection current human flu vaccines might offer.