An isolated, fatal case of H5N1 or avian influenza has been announced in Alberta. The infected person, an Alberta woman who recently travelled to Beijing, China, died Jan. 3.

Here are some common questions and answers about the illness:

What is H5N1 bird flu?

The H5N1 type of influenza is a bird flu virus that can cause outbreaks in poultry.

From 2003 until Dec. 20, 2013, the World Health Organization said there have been 648 cases confirmed in humans from 15 countries. Of those, 384 or nearly 60 per cent died.

How serious is it to humans?

While H5N1 avian flu remains a rare event among people, it is fatal in 60 per cent of cases.

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Deputy Chief Public Health Officer Gregory Taylor, Dr. Howard Njoo (left) and Dr. Theresa Tam announced the first reported death in North America from H5N1 bird flu on Wednesday. (Adrian Wyld/Canadian Press)

Dr. Michael Gardam of Toronto University Health Network told CBC-TV's The National that the virus has been on scientists' radar for more than a decade.

"Of course, that's the cases we know of. We do know that with all of these viruses there are people that may be less sick, but we don't know about those people. So far now, it is considered a very deadly virus."

Does it spread easily between people?

Most cases have been found in people who have spent time around infected birds.

"This is a bird virus that very, very rarely jumps into humans, and we really don’t have evidence of this spreading person to person," Gardam said.

"This is a virus that has genetically not developed the capacity to spread readily from person to person. That distinguishes it from the usual kinds of influenza that we know," agreed Dr. William Schaffner, chairman of the department of preventative medicine at Vanderbilt University in Nashville, in an interview with CBC News.

Schaffner said there have been rare occasions of person to person transmission of bird flu, but only through "very close, prolonged, contact."

Why are health officials watching H5N1 so closely?

Health officials are on the watch for flu viruses, including H5N1, that could gain the ability to spread rapidly between people and cause severe disease.

What are the symptoms?

Symptoms include:

  • Fever and cough.
  • Acute respiratory distress.
  • Shortness of breath/difficulty breathing.
  • Abdominal pain.
  • Diarrhea.

In the case of Alberta's H5N1 death announced on Wednesday, health officials said the patient presented with fever, malaise and headache consistent with a subset of the illness.

What precautions should travellers take?

There is no evidence of the virus spreading between people travelling on airplanes, health officials stressed.

The patient died after travelling to Beijing. The Public Health Agency said its usual advice to travellers applies, such as avoiding contact with chickens, ducks, wild birds and surfaces with bird droppings. Poultry and eggs should also be well cooked.

What is the treatment?

Antiviral drugs may be able to reduce the severity and duration of illness, if taken early enough.

How is it diagnosed?

The U.S. Centers for Disease Control and Prevention says H5N1 cannot be diagnosed by symptoms alone. It is usually diagnosed by collecting a swab from the nose or throat in the first few days of illness then testing for signs of the virus.

What about seasonal flu?

The H5N1 bird flu is not the same as the seasonal flu.

The H1N1 strain first identified in 2009 is also the main version of flu circulating this year, according to the Public Health Agency of Canada's FluWatch.

This year's flu vaccine protects against the H1N1 strain.

H5N1 AVIAN FLU CASES