WELLINGTON, New Zealand (AP) – New Zealand reported suspected swine flu cases Monday among a second group of teenagers returning from Mexico, as Asian nations with potent memories of SARS and bird flu outbreaks screened travelers for illness with thermal scanners.

Hong Kong assigned a team of scientists to find a quick test for the latest virus to raise fears of a pandemic, following confirmed human cases of the disease in Mexico, United States and Canada.

In the U.S., at least 11 cases of swine flu have been confirmed. Canada’s chief public health officer, Dr. David Butler-Jones, said six cases had been confirmed there, and all had links to people who had traveled to Mexico.

More than 100 people in Mexico are believed to have died from the new flu and more than 1,600 sickened, prompting widespread school closures and other measures.

In New Zealand, Health Minister Tony Ryall said three students among a group of 15 that had just come back from a class trip to Mexico had mild flu and were being tested for swine flu. On Sunday, officials said 10 students from a separate group that also were in Mexico “likely” have swine flu.

Forty people – students, their families and some teachers – had voluntarily quarantined themselves at home.

In Hong Kong, Thomas Tsang, controller for Hong Kong’s Center for Health Protection, said the government and the territory’s universities aim to jointly develop a quick test for the new flu strain in a week or two that will return results in four to six hours, compared to existing tests that can take two or three days.

He said in an interview with radio RTHK that researchers will develop the test based on genetic information on the current swine flu virus provided by the World Health Organization.

WHO Director-General Margaret Chan on Sunday said the outbreak had “pandemic potential” and held teleconferences with staff and flu experts around the world. She urged governments to step up their surveillance of suspicious outbreaks.

Governments including China, Russia and Taiwan began planning to put anyone with symptoms of the deadly virus under quarantine. Other governments were increasing their screening of pigs and pork imports from the Americas or banning them outright.

Many nations issued travel warnings for Mexico.

Israel said a man who had recently visited Mexico had been hospitalized while authorities try to determine if he has the disease. French officials said four people who recently returned from Mexico were possible swine flu cases. In Spain, three people were under observation for the flu.

In Singapore, the health ministry said it began using thermal scanners Sunday at Changi International Airport to check passengers arriving from the United States for symptoms of swine flu. The checks will be extended to all passengers by Wednesday, it said.

Hong Kong and Taiwan said visitors returning from flu-affected areas with fevers would be quarantined. China said anyone experiencing flu-like symptoms within two weeks of arrival had to report to authorities. A Russian health agency said passengers from North America running a fever would be quarantined until the cause is determined.

Tokyo’s Narita airport installed a device to test the temperatures of passengers arriving from Mexico. Indonesia increased surveillance at all entry points for travelers with flu-like symptoms.

Many measures recalled those taken across Asia during the 2003 severe acute respiratory syndrome, or SARS, epidemic and used more recently to monitor bird flu.

Drawing on their fight against SARS, experts in Hong Kong warned that swine flu seems harder to detect early and may spread faster.

“This is a flu virus. SARS was a new virus belonging to a different group. The thing about flu viruses is that they incubate before you have any symptoms,” said John Simon, a scientific adviser to Hong Kong’s Center for Health Protection.

“Border guardings, thermal imaging will not detect much of this flu when it eventually comes through because a lot of people will be incubating,” he said.

A New Zealand student who was among those sickened said her group had stayed with Mexican families in their homes during the last few days of their trip, to better their Spanish language skills.

“Some of us were getting coughs and stuff like that a few days before the end of our trip,” the student, who was not named, told New Zealand’s National Radio.

She said the symptoms were not bothering her so much, but the that official reaction and being quarantined was a strange experience.

“It’s a bit movie-like, it doesn’t really feel real,” she said.

Updated map of swine flu cases:

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