Influenza viruses are grouped into three types---A, B and C. Influenza A viruses have 16 H subtypes and 9 N subtypes. Only H5 and H7 subtypes can be highly pathogenic, however, not all H5 and H7 subtypes are. When introduced into poultry flocks, H5 and H7 viruses usually have low pathogenicity, but when allowed to circulate, they can mutate into an HPAI form. It is important to report and monitor the presence of an H5 or H7 virus in a flock of birds.

Migratory waterfowl are reservoirs for avian influenza. They harbour the virus with no ill effects to themselves. Evidence suggests that direct or indirect contact with migratory waterfowl is often the source of infection in commercial poultry flocks. Transmission can also occur through contact with infected poultry, poultry products, vehicles, equipment, egg flats, clothing and footwear. Contaminated feed and water are common sources of infection.

The H5N1 strain has a limited ability to infect humans. Please see the table below, which summarizes the countries that have reported outbreaks in birds, as well as the number of humans infected and the number of deaths due to H5N1, since December 2003.

Outbreaks of low pathogenic avian influenza were detected and eradicated in New Jersey, Maryland, Delaware and Pennsylvania in the United States and in the Netherlands in the spring of 2004. A highly pathogenic strain (H5N2) was also confirmed and eradicated in Texas that same year.

An outbreak of HPAI (H7N3) occurred in British Columbia's Fraser Valley in February 2004. The virus was eradicated by the Canadian Food Inspection Agency (CFIA). An outbreak of low pathogenic avian influenza (H5) was reported in a commercial duck and goose farm in British Columbia in November 2005. This is NOT the same virus strain affecting Southeast Asia and parts of Eastern Europe.

The World Health Organization has developed a map to show where H5N1 has occurred in domestic poultry and wild birds since 2003. There is also a map that shows affected countries with confirmed human cases of H5N1 since 2003.

More information about Avian Influenza can be found on a website sponsored by the National Chicken Council, National Turkey Federation and Egg Safety Centre.

Highly Pathogenic Avian Influenza (H5) Global Update
(as of July 26, 2006)

Avian Influenza---Global Update

COUNTRY	DATE FIRST REPORTED	STRAIN	HUMAN CASES	HUMAN DEATHS
South Korea	December 2003	H5N1 and H5N2
Vietnam	January 2004	H5N1	93	42
Japan	January 2004	H5N1 and H5N2
Taiwan	January 2004	H5N2
Thailand	January 2004	H5N1	23	15
Cambodia	January 2004	H5N1	6	6
Indonesia	January 2004	H5N1	54	42
Hong Kong	January 2004	H5N1
Laos	January 2004	H5
Malaysia	August 2004	H5N1
China	January 2004	H5N1	19	12
Texas, USA	February 2004	H5N1
Kazhakstan	August 2005	H5N1
Mongolia	August 2005	H5N1
Philippines	July 2005	H5
Russia	July 2005	H5N1
Turkey	October 2005	H5N1	12	4
Romania	October 2005	H5N1
Croatia	November 2005	H5N1
Ukraine	December 2005	H5N1
Iraq	January 2006	H5N1	2	2
Bulgaria	February 2006	H5N1
Nigeria	February 2006	H5N1
Niger	February 2006	H5N1
Iran	February 2006	H5N1
Slovakia	February 2006	H5N1
Poland	March 2006	H5N1
Albania	March 2006	H5N1
Sweden	March 2006	H5N1
Azerbaijan	March 2006	H5N1	8	5
Austria	March 2006	H5N1
Bosnia and Herzegovina	March 2006	H5
Serbia and Montenegro	March 2006	H5N1
Cameroon	March 2006	H5N1
Slovenia	March 2006	H5N1
Egypt	March 2006	H5N1	14	6
Georgia	March 2006	H5
Germany	March 2006	H5N1
India	March 2006	H5N1
Israel	March 2006	H5N1
Italy	March 2006	H5N1
Switzerland	March 2006	H5N1
Djibouti	June 2006	H5N1	1	0
		TOTAL:	232	134

The contents of this page are no longer available.

For more information about the content of this document, contact Gerald Hauer.
This document is maintained by Sheila Hart.
This information published to the web on January 30, 2004.
Last Reviewed/Revised on August 1, 2006.