(AP) -- Canada became the third country to confirm human cases of swine flu Sunday as global health officials considered whether to raise the global pandemic alert level.
Nations from New Zealand to France also reported suspected cases and some warned citizens against travel to North America while others planned quarantines, tightened rules on pork imports and tested airline passengers for fevers.
Nova Scotia's chief public health officer, Dr. Robert Strang, said the east coast Canadian province had confirmed four "very mild" cases of swine flu in students ranging in age from 12 to 17 or 18. All are recovering, he said.
"It was acquired in Mexico, brought home and spread," Strang said.
The news follows the World Health Organization's decision Saturday to declare the outbreak first detected in Mexico and the United States a "public health emergency of international concern."
A senior World Health Organization official said the agency's emergency committee will meet for a second time Tuesday to examine the extent to which the virus has spread before deciding whether to increase the pandemic alert beyond phase 3.
The same strain of the A/H1N1 swine flu virus has been detected in several locations in Mexico and the United States, and it appears to be spreading directly from human to human, said Keiji Fukuda, WHO's assistant director-general in charge of health security.
Mexico's health minister says the disease has killed up to 86 people and likely sickened up to 1,400 since April 13. U.S. officials say the virus has been found in New York, California, Texas, Kansas and Ohio, but so far no fatalities have been reported.
Governments including China, Russia and Taiwan began planning to put anyone with symptoms of the deadly virus under quarantine
Others were increasing their screening of pigs and pork imports from the Americas or banning them outright despite health officials' reassurances that it was safe to eat thoroughly cooked pork.
Some nations issued travel warnings for Mexico and the United States.
WHO's emergency committee is still trying to determine exactly how the virus has spread, Fukuda said
"Right now we have cases occurring in a couple of different countries and in multiple locations," he said. "But we also know that in the modern world that cases can simply move around from single locations and not really become established."
Raising the pandemic alert phase could entail issuing specific recommendations to countries on how to halt the disease. So far, WHO has only urged governments to step up their surveillance of suspicious outbreaks.
WHO Director-General Margaret Chan called the outbreak a public health emergency of "pandemic potential" because the virus can pass from human to human.
Her agency was considering whether to issue nonbinding recommendations on travel and trade restrictions, and even border closures. It is up to governments to decide whether to follow the advice.
"Countries are encouraged to do anything that they feel would be a precautionary measure," WHO spokeswoman Aphaluck Bhatiasevi said. "All countries need to enhance their monitoring."
New Zealand said that 10 students who took a school trip to Mexico "likely" had swine flu. Israel said a man who had recently visited Mexico had been hospitalized while authorities try to determine whether he had the disease. French Health Ministry officials said four possible cases of swine flu in two regions are currently under investigation. All recently returned from Mexico.
Spain's Health Ministry said three people who just returned from Mexico were under observation in hospitals in the northern Basque region, in southeastern Albacete and the Mediterranean port city of Valencia.
Hong Kong and Taiwan said visitors who came back from flu-affected areas with fevers would be quarantined. China said anyone experiencing flu-like symptoms within two weeks of arrival from an affected area had to report to authorities. A Russian health agency said any passenger from North America running a fever would be quarantined until the cause of the fever 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 - using devices at airports that were put in place years ago to monitor for severe acute respiratory syndrome, or SARS, and bird flu. It said it was ready to quarantine suspected victims if necessary.
Hong Kong and South Korea warned against travel to the Mexican capital and three affected provinces. Italy, Poland and Venezuela also advised their citizens to postpone travel to affected areas of Mexico and the United States.
Symptoms of the flu-like illness include a fever of more than 100 degrees Fahrenheit (37.8 degrees Celsius), body aches, coughing, a sore throat, respiratory congestion and, in some cases, vomiting and diarrhea.
The virus is usually contracted through direct contact with pigs, but Joseph Domenech, chief of animal health service at U.N. Food and Agriculture Agency in Rome, said all indications were that the virus is being spread through human-to-human transmission.
No vaccine specifically protects against swine flu, and it is unclear how much protection current human flu vaccines might offer.
Russia banned the import of meat products from Mexico, California, Texas and Kansas. South Korea said it would increase the number of its influenza virus checks on pork products from Mexico and the U.S.
On the Net:
WHO swine flu page: http://www.who.int/csr/disease/swineflu/en/index.html
©2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Explore further: Raw tuna suspected as source of salmonella outbreak: CDC