H5N1: What you need to know about Avian Flu

A duck stands near a warning sign at an amusement park in Beijing, China, Wednesday, April 3, 2013. (AP / Alexander F. Yuan)

With confirmation of the first death from H5N1 in Canada, here’s what you need to know about the virus.

What is H5N1?

H5N1 is a highly pathogenic avian flu virus commonly found in domestic poultry across certain regions of Asia and the Middle East. While human cases of the virus infection are very rare and it is difficult to transmit the infection from person to person, the mortality rate for infected humans is about 60 per cent.

The virus can infect the respiratory tract and lead to serious illnesses such as pneumonia, respiratory failure and death.

How many people have been infected with the virus?

More than 600 people have contracted H5N1 worldwide since 2003, with countries such as Egypt and Vietnam reporting the highest number of cases to date.

According to the World Health Organization, there were 38 known cases of human H5N1 infections in 2013 and 24 reported deaths, mostly in Cambodia.

How is H5N1 contracted?

Most patients infected with the H5N1 virus have come in close contact with sick or dead infected poultry.

Humans may also contract the virus after prolonged exposure to H5N1 environments such as live poultry markets, travelling abroad, or coming in contact with an infected H5N1 patient.

Dr. Neil Rau, an infectious diseases specialist, tells CTV that the exchange of H5N1 from human-to-human contact is very rare.

“You don’t get sustained chains of transmission, where it goes from one person who had contact with the birds to another person, and then again to another wave of people. I think the most that’s ever been seen has been two chains, but most of the time, you don’t actually see close contact giving rise to a sustained spread.”

You cannot contract H5N1 from properly handled and cooked poultry and eggs since the virus is sensitive to heat. According to the World Health Organization, the majority of human H5N1 cases have been linked to home slaughtering and the handling of diseased poultry before cooking, which remains the highest risk to infection.

What are the symptoms?

Symptoms of the virus include fever, cough, sore throat and muscle aches. Some patients may experience abdominal aches, chest pain and diarrhoea. Experts say the virus can progress into severe respiratory illnesses and cause seizures, organ failure and death.

Rau says that while initial H5N1 symptoms may resemble those associated with seasonal flu, H5N1 can progress very rapidly.

“The typical symptoms would be very much like another, typical seasonal flu,” he said.

“But the difference with bird flu is that it actually progresses to pneumonia, the patient becomes breathless and then has respiratory distress.”

How is H5N1 treated in humans?

While candidate vaccines to prevent H5N1 have been developed, they are not ready for widespread public use and none has been approved in Canada.

Seasonal flu vaccines do not provide protection against the H5N1 virus. The World Health Organization warns that any patient showing signs of H5N1 infections should be treated in hospital as they may require intensive care. The antiviral medicine known as ‘Oseltamivir’ has shown to reduce the severity of H5N1 illnesses and should be used in all cases.

Sources: WHO, CDC