A South Korean quarantine officer, left, checks the temperature of a Japanese passenger to look for possible infection with swine flu at Incheon International Airport in South Korea on Wednesday. (Yonhap, Lee Jung-hun/Associated Press)

The World Health Organization on Wednesday raised its global pandemic alert level to five — its second highest level — meaning a pandemic is imminent and countries must finalize preparations to deal with the outbreak of swine flu.

"Based on assessments of all available information and following several expert consultations, I have decided to raise the current level of influenza pandemic alert from Phase 4 to Phase 5," WHO director general Margaret Chan said during a briefing from the organization's headquarters in Geneva.

Phase 5 is called when there is human-to-human spread of a virus in at least two countries in one region, according to the WHO's pandemic response guidelines.

Margaret Chan, the director general of WHO, raised the global pandemic alert level to five on Wednesday. It's the organization's second-highest alert level. (CBC)

Chan said the new alert level is a signal for governments around the world to take action with "increased urgency and at an accelerated pace."

"All countries should immediately activate their pandemic preparedness plans," she said. "Countries should remain on high alert for unusual outbreaks of influenza-like illness and severe pneumonia."

Chan said the spread of the virus must be taken "very seriously" but emphasized that people should not panic.

"It is important that we should not overkill, and we need to maintain a level of calmness," she said.

She praised the governments of the U.S. and Canada for their support to the WHO and Mexico, where the outbreak is believed to have originated. Chan also thanked Mexico for its "openness and transparency" in providing information about the disease.

Meanwhile, Mexican President Felipe Calderon urged Mexicans to stay at home with their families during a partial shutdown of the economy from May 1 to 5, in an attempt to limit the spread of the outbreak, according to Reuters.

Calderon made the request during his first television address Wednesday to the Mexican people since the flu crisis broke last week.

Mexico will suspend non-essential work and services, including some government ministries and private businesses, for five days starting on Friday, he said.

Global cases on the rise

Earlier Wednesday, WHO assistant director Dr. Keiji Fukuda said evidence suggests the spread of the virus that causes human cases of swine flu is continuing and is not likely to slow.

The virus is a new swine influenza virus but "it is now behaving more like a human influenza virus with transmission going from person to person," Fukuda said following an emergency scientific review of the outbreak.

There is no evidence that humans are being infected by contact with pigs or by consumption of pork, he said.

The WHO said Wednesday that laboratory tests have confirmed 114 cases in seven countries, including:

• 19 cases in Canada.
• 91 cases in U.S. with one reported death.
• 26 cases in Mexico with seven reported deaths.
• Two cases in Israel.
• Four cases in Spain.
• Two cases in the United Kingdom.
• Two cases in New Zealand.

Peru diagnosed its first case of swine flu late Wednesday and immediately announced it was suspending all commercial flights arriving from Mexico.

The patient is an Argentine woman who lives in California and had recently been in Mexico, according to Reuters.

In Lima, Health Minister Oscar Ugarte also said three other suspected cases of swine flu were being watched.

Switzerland followed early Thursday, reporting its first confirmed case of the infection. A man in the town of Baden, northwest of Zurich, was being treated in hospital, according to Agence France-Presse and Swiss news agencies. Twenty-four other suspected cases of the disease are being investigated in Switzerland, all of them in people who have recently returned from Mexico.

Fukuda said officials are aware that other deaths are being reported in various countries and that WHO is updating its list as it is officially informed of the cases.

The illness is consistent with seasonal influenza, though the number of cases of diarrhea associated with the virus appears to be higher, he said.

Officials are still trying to determine the frequency at which people are developing a severe case of the illness, he said.

WHO has not called for travel restrictions or border closures. However, several cruise lines, tours and flights destined for Mexico have been cancelled, including several operated by Air Canada, WestJet and Transat.

Fukuda said the WHO still cannot offer any explanation why cases of the infection in Mexico are more severe than in other countries and are still examining the transmissibility of the virus.

More cases in U.S.

The United States has 91 confirmed cases of swine flu, including the death of a Mexican infant in Texas, the U.S. Centers for Disease Control said Wednesday.

Dr. Richard Besser, acting director of the CDC, announced the death at a news conference updating the number of confirmed cases in 10 states, up from five states on Tuesday.

New York reported 51 cases, while there were 16 in Texas and 14 in California. Two cases have been confirmed in Kansas, Massachusetts and Michigan, while single cases have been reported in Arizona, Indiana, Nevada and Ohio.

The U.S. is seeing a broader age range among cases, Besser said, with 64 per cent of patients under age 18. There have been five hospitalizations, including the 23-month-old child, who was from Mexico.

Child was visiting U.S.

The child fell ill on April 13 while visiting family in Brownsville in southern Texas, said David Persse, director of Houston EMS.

"The patient became quite ill rather rapidly and was transferred the next day to a hospital here in Houston," Persse said.

The child received "aggressive treatment" but died on Monday, Persse said.

The child's family members and other people who were in contact have not fallen ill and are being attended to by medical staff, Persse said.

The death "doesn't change the landscape here in Houston," Persse said. "We still know the virus is here in the United States. We know it is in Texas. We know we need to take our personal precautions."

With 16 confirmed cases in the state, Texas Gov. Rick Perry issued a disaster proclamation Wednesday.

State health officials also confirmed a second child in Texas, another 23-month-old, has swine flu and is in critical care.

A pregnant woman in the state also "likely" has swine flu, said Dr. David Lakey, the commissioner of the Texas Department of State Health Services. The woman had an emergency caesarean section and is in critical condition. The baby is fine, said Lakey.

'Utmost precautions'

Meanwhile in Washington on Wednesday, U.S. President Barack Obama said schools with confirmed cases of the H1N1 virus should strongly consider temporarily closing.

Obama said the government is doing all it can to control the virus and will do whatever is necessary to control its spread.

Obama asked Congress on Tuesday for $1.5 billion in emergency funds to help build drug stockpiles and monitor future cases, as well as help international efforts to avoid a pandemic.

"This is obviously a serious situation," Obama said, "serious enough to take the utmost precautions."

He said parents should also be making alternate arrangements for their children should temporary closures become mandatory.

Dealing with the spread of the virus is "a marathon, not a sprint," U.S. Homeland Security Secretary Janet Napolitano told a senate committee on Wednesday.

"We have been preparing as if we are facing a true pandemic, even though we don't know the ultimate scope of what will occur," Napolitano said.

The U.S. has a stockpile of about 50 million courses of antivirals. About 25 per cent of the state portion of the antivirals have been released and is being transported to Arizona, California, Texas and Utah, she said. More antivirals are expected to be available by May 3.

The nature of the virus does not yet warrant the U.S. closing its borders, she said.

More confirmed cases in Europe

Meanwhile, four cases have been confirmed in Germany, the country's disease control centre said Wednesday.

The German cases include two women, ages 22 and 37, and a man in his 30s, said officials with the Robert Koch Institute said Wednesday. Two of the patients are from towns in Bavaria. The third is from Hamburg.

Officials said all three patients recently returned from trips to Mexico.

There are five other suspected cases in Germany, and they're believed to be in Bavaria and the state of North Rhine-Westphalia, according to officials.

Austria's Health Ministry also said Wednesday that a 28-year-old woman who had recently returned from a trip to Guatemala via Mexico City had been confirmed as having the virus. She is recovering, officials said.

In Britain, the confirmed human cases jumped to five on Wednesday, while the number of cases rose to four in Spain.

Polish health officials reported Wednesday that they are also awaiting test results for two suspected cases.

A 12-year-old girl from the southwest England town of Torbay Brown and two adults from London and Birmingham were the new British cases confirmed to have swine flu Wednesday.

All three had visited Mexico, were receiving antiviral drugs and were responding well to treatment, said British Prime Minister Gordon Brown at a news conference on Wednesday.

Brown said health officials were ordering extra medicine and "a great deal more" face masks to deal with the virus.

"We've decided to build stocks of antivirals, from 35 million to 50 million," Brown said, adding that the government had set up enhanced airport checks and was preparing to mail swine flu information leaflets to every household in Britain.

Asia escapes illness so far

New Zealand confirmed more cases on Wednesday, bringing its total to 14. Officials said all patients were responding well to treatment with antiviral drugs and were in voluntary quarantine at home.

There are 44 other possible cases in New Zealand, said Dr. Julia Peters, a senior regional health official, and testing is underway.

In Australia, more than 100 people with flu symptoms are being tested for possible swine flu, according to officials.

There have not yet been any confirmed cases in Asia, where governments have taken strict precautions at airports.

With files from The Associated Press