China bans Canadian poultry import due to H7N3 Bird Flu outbreak

China has banned the import of live birds from Canada after samples from a poultry farm tested positive for a strain of avian influenza virus, called H7N3. In order to ward off the avian influenza, a contagious disease of animals caused by viruses that normally infect only birds and, less commonly, pigs, all poultry imports and relative products shipped from Canada after September 23 should be destroyed, the Chinese health authorities warned.

The decision jointly made by the Ministry of Agriculture and the General Administration of Quality Supervision, Inspection and Quarantine came after the Canadian Food Inspection Agency last week reported the detection of high pathogenic form of avian influenza virus subtype H7N3 on a farm in a commercial poultry operation in Saskatchewan, west Canada.

The CFIA quarantined the poultry farm after discovering H7N3 avian influenza virus, which is not lethal to humans. The affected farm is a broiler-breeding operation. The Canadian health agency claimed the detected virus was not the same as the strain circulating in Asia, Africa and Europe, which has been associated with human illness.

"We're assuming all of the birds at this operation are now infected," said Dr. Jim Clark, the CFIA’s manager of the Avian Influenza Working Group.

The ban that covers all poultry and related products follows an outbreak alert issued two days back by the World Organization for Animal Health (OIE), saying that the highly pathogenic virus has been confirmed in a chicken broiler breeder flock in Saskatchewan.

The outbreak of virus H7N3, lethal to birds but not to humans, killed hundreds of chickens. Approximately 540 roosters have died in one barn containing approximately 600 birds, while another 49,100 roosters and broiler breeders held in other nine barns nearby are susceptible, the Paris-based international organization warned.

Japan has also imposed an import ban on all poultry and relative products from Canada and the Japanese agriculture ministry said it will seek detailed information from the Canadian government.

Likewise, the U.S. Department of Agriculture has indefinitely barred imports of all poultry products from the affected Canadian farm.

This is the second time the H7N3 strain has been detected in Canada, the first case of H7N3 was discovered in poultry in Canada in April and May 2004. On March 9, 2004, Canada reported the detection of both low and high pathogenic forms of avian influenza virus subtype H7N3 on a farm in Fraser Valley, British Columbia. The affected farm was a broiler-breeding operation comprised of two units of approximately 9,000 birds each.

Of the hundreds of strains of bird flu viruses, only four are known to have caused human infections, which include H5N1, H7N3, H7N7, and H9N2. Generally, human infection with these viruses has resulted in mild symptoms and little severe illness, with one notable exception, the highly pathogenic H5N1 virus.

H5N1, also known as A(H5N1), is a subtype of the Influenza A virus that is capable of causing illness in many animal species, including humans, while a bird-adapted strain of H5N1, called HPAI A(H5N1) for "highly pathogenic avian influenza virus of type A of subtype H5N1", is the causative agent of H5N1 flu, commonly known as "avian influenza" or simply "bird flu", and is endemic in many bird populations, especially in Southeast Asia.

According to the WHO data, the strain of bird flu virus has so far infected 307 people and killed 186 of them, mostly in Southeast Asia, it began ravaging Asian poultry stocks in 2003.

WHO, Food and Agriculture Organization (FAO), World Organization for Animal Health (OIE) in collaboration with United States are looking into minimizing the risk of spreading of this disease and taking steps to avoid this to turn into a pandemic on a global level.