Mexican officials have enlisted the help of Winnipeg's microbiology lab to help test blood samples from victims of a severe "influenza-like" illnesses that has caused 60 deaths in that country.

Scientists here are trying to pinpoint the virus and better identify why the bug is causing such severe illness. There results are expected Friday afternoon.

There are more than 800 cases of the currently unidentified illness.

Canada remains on high alert for suspected cases that may have been brought back here by Canadian travellers.

The World Health Organization says it has activated its Strategic Health Operations Centre -- its command and control centre for acute public health events, because of the sudden spike in flu illnesses in Mexico.

WHO spokeswoman Fadela Chaib said Mexican authorities had noticed unusual flu activity in March and April, a period when the flu season of the country of 105 million should have drawn to a close.

"To date, there have been some 800 suspected cases with flu-like illness, with 57 deaths in the Mexico City area," she told a news briefing Friday. "Similar cases have since been found in San Luis Potosi in central Mexico. The number of suspected cases is 24 suspected cases and three deaths."

At least one Canadian may have been affected, after being treated for severe pneumonia following a trip from Mexico. That patient has since recovered but the source of his illness remain unclear.

Swine flu in southern U.S.

At the same time, the U.S. Centers for Disease Control and Prevention now says that seven people had been diagnosed with a new kind of swine flu in California and Texas, which share a border with Mexico.

The WHO is also concerned about the swine flu outbreak, which may or may not be related to the illnesses in Mexico.

It says the virus is a never-before-seen mixture of viruses typical among pigs, birds and humans. Yet, the virus does not appear to create severe illness and all seven patients have recovered.

"We don't yet know the extent of the problem," said Dr. Anne Schuchat, the director of respiratory diseases for the agency, "but we don't think this is a time for major concern."

Nevertheless, the cases are unusual because it appears none of the patients had come in contact with pigs, suggesting that an animal virus is being transmitted from person to person.

Dr. Allison McGeer, an infectious disease specialist at Toronto's Mount Sinai hospital, says Canadian health officials, made wiser by their experience with SARS, are treating both outbreaks seriously.

"SARS taught us that it can take a very little time to move a virus all around the globe," she told CTV Newsnet Thursday.

"One of the things we've committed to around the world is enhanced surveillance and being really sure that we don't miss these new viruses."

McGeer added that the chances that the Mexican outbreak is the start of a new flu pandemic are "pretty low."

The flu-like condition in Mexico has so far affected healthy young adults between the ages 25 and 44, mostly in south and central areas of the country, but not the tourist areas on the coast.

The victims showed influenza-like symptoms that progressed to "severe respiratory distress" within five days. Some have had to be placed on respirators, while others have died.

Health officials say specimens collected from the patients have tested positive for both A and B strains of influenza. Further tests at Canada's National Microbiology Laboratory in Winnipeg should help to better identify the strain.

Infections disease expert Dr. Neil Rau says we still need a lot more information, "especially lab information," before we can understand the threat this flu might be causing.

"The question is whether it's the usual seasonal garden-variety flu or are we dealing with something new," Rau told Canada AM Friday.

"We're hearing that up to 30 per cent of people who get this illness are dying from it and that part's scary. But on the other hand, it just might be a bad flu year."

"The thing to watch is how the next few days go. If there are more cases each day, or there are more deaths, or if there is exportation of cases to other countries in people returning from Mexico, that's going to mean something."

Canadian health officials have issued an advisory to health authorities to be on the lookout for travellers who have recently returned from Mexico and develop flu-like symptoms.

Any Canadian who has returned from Mexico within the last two weeks and is suffering the following symptoms should contact a physician:

- fever

- cough

- sore throat

- shortness of breath

- muscle and joint pain

With files from the Canadian Press