Information

December 1997

Avian Flu in Hong Kong

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What is the "bird flu"?
The avian flu, or the so-called "bird flu," is a strain of influenza virus called influenza A (H5N1) and is a recognized cause of disease in chickens and other birds. This pathogen has been causing fatal outbreaks in poultry flocks in rural Hong Kong and Guangdong Province, China this year. The recent cases in Hong Kong appear to be the first fully documented cases where avian flu has been transferred directly from birds to humans. Currently, there is no documented transmission of this virus from human to human.

Is there a human vaccine for the avian flu?
Not at the moment. The World Health Organization is developing seed strains to develop a vaccine. Once these are available, it would then take a minimum of 3½ months to produce the vaccine.

Has there ever been a case of avian flu in a human in Canada?
No. The cases in Hong Kong are the first documented cases in the world.

How many confirmed cases of the avian flu have been reported in Hong Kong?
Authorities in Hong Kong are aware of several confirmed and one possible case of the influenza A H5N1 strain. A three-year-old child was ill in May and died of complications. The subsequent cases have been reported since November.

This site has been linked to the Hong Kong Department of Health website to enable readers to access the most up to date official reports on numbers of cases of H5N1 infection. To access this site click here. (http://www.info.gov.hk/info/flu/eng/index.htm)

How were these people exposed to the avian flu?
The first case of the avian flu was in contact with infected birds. The source of infection of the others is being investigated. These other people have lived in different parts of Hong Kong and have had no contact with each other or any apparent common activities.

Is it true that some staff treating the recent cases in Hong Kong and family contacts of the cases have caught the flu?
Nine medical staff who treated those with the avian flu subsequently became ill with respiratory illness. However, there is no laboratory evidence that they have influenza A H5N1. Tests on the family contacts who have become ill are still being evaluated. There is currently no evidence to confirm that their infections are related to the avian flu. Hong Kong authorities are closely monitoring the cases. Currently, there are various other respiratory viruses, including other types of influenza in the Hong Kong community.

Are there any cases in Canada of birds with active avian flu?
There have been no reported cases of this H5N1 virus in poultry in Canada in 1997.

Could the avian flu cause pandemic disease in humans?
To cause a pandemic or worldwide epidemic in humans, the virus must spread easily from person to person. At the present time, it has not been determined that the virus can spread between persons and cause disease. The potential for this virus to cause a pandemic remains hypothetical until it is shown that others can easily acquire an infection from ill persons.

What action is Health Canada taking?
Health Canada is always concerned about any real or potential threat to the health of Canadians. For this reason Health Canada's Laboratory Centre For Disease Control (LCDC) is carefully monitoring the situation in Hong Kong. In addition, LCDC has an extensive flu surveillance program called FluWatch, which monitors influenza across Canada on a weekly basis and is a collaborative project involving provincial and territorial health departments, laboratories and LCDC.

Will the current flu vaccine protect people against the avian flu?
The current vaccine will not provide protection against the avian virus because it is for different flu strains. Commercial vaccine production for this particular flu will not be considered unless there is evidence that the virus can be easily transmitted between persons. Work has been started on identifying suitable virus strains that could be used for a vaccine if that becomes necessary.

Why did the avian flu in humans begin in China?
There is no definite answer to this question. However, this situation could have occurred anywhere where humans have close contact with infected birds.

Could this virus get into Canada?
Any virus that is easily passed from person to person has the potential to spread across and between populations. Health Canada is continuously assessing the information from Hong Kong and monitoring "flu activity" in this country.

Do we know how this virus spread from birds into humans?
Many species of birds and animals are affected by influenza viruses and H5N1, for example, is a known cause of disease in chickens. We also know that flu viruses can readily adapt and that sometimes the virus will learn to attack humans. We have thought that this usually requires an intermediate host, such as a pig, which can be infected by both the bird and human strains. In this instance, the avian flu appears to have directly infected humans.

Are Chinese people at greater risk from this virus?
We have no evidence that this is the case. Health Canada is carefully monitoring the current situation in Hong Kong and in Canada.

What advice would you give to people travelling to Hong Kong?
Current information does not indicate that this avian influenza virus is a risk to the health of Canadians either in Canada or those travelling to Asia. As a precaution, it is advised that unnecessary contact with live poultry should be avoided. Also, since there are strains of influenza circulating in China that are known to cause widespread human disease, a flu shot is recommended for those over 65 years of age, living in a chronic care facility, or with chronic medical conditions such as bronchitis, emphysema, heart disease, diabetes, kidney disease or cancer.

Will travellers from Hong Kong be screened for the avian virus?
Since there is no evidence that this avian influenza virus is a risk to the health of Canadians either in Canada or those travelling to Asia, there is no additional danger to travellers in airports than during the average flu season.

Is there any risk in eating chicken?
No.

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