China has, so far, confirmed 14 cases in the recent outbreak of H7N9 bird flu — six in Shanghai, four in Jiangsu, three in Zhejiang and one in Anhui. They are the first known human infections of the lesser-known strain. To date, four people have died in Shanghai and two in Zhejiang.
The Chinese authorities still do not know where the virus came from or how it is spread. Given the high level of cross-strait travel, Taiwanese are now becoming increasingly worried about the H7N9 strain.
Over the past few years, the Bureau of Animal and Plant Health Inspection and Quarantine has found H5 and H7 avian influenza viruses in the excrement of poultry, migratory birds and water fowl.
However, apart from a few farms where the highly pathogenic strain of H5N2 was found and in which cases all the affected birds were culled, birds from farms that show up positive for the low pathogenic H5 and H7 avian influenza viruses were still allowed to be sold.
On Tuesday, the bureau said that in 2009 and 2011, the excrement of migratory birds in Greater Tainan’s Sihcao (四草) area and in Yilan County’s Jiaosi Township (礁溪) tested positive for the H7N9 virus. The bureau added that at that time the virus had not spread to any nearby poultry farms.
The nation does not cull birds on farms that have been affected by low-pathogenic bird flu, but China’s latest outbreak of H7N9 bird flu highlights that the bureau’s current policy of not culling birds that have been affected by low-pathogenic viruses requires further examination and detailed discussion.
If we look at the way developed countries report outbreaks of bird flu to the World Organization for Animal Health, we see that when farms in these countries experience outbreaks of H5 and H7 avian influenza viruses — regardless of whether these viruses are highly pathogenic or low-pathogenic — all animals in the affected areas are culled. This also shows that the nation’s epidemic prevention policies for bird flu are the same as those in place in some less developed countries in the Southeast Asian region and in Africa.
A molecular biological analysis was performed on the H7N9 virus in China, which found that it only contained a single alkaline amino acid, meaning that this virus is avirulent and not very pathogenic to poultry. This is an important warning in terms of the nation’s current bird flu prevention policies.
The public should ask disease prevention bodies in Taiwan how they intend to handle the situation if the fatal H7N9 virus is discovered on Taiwanese poultry farms. Do they plan to cull all birds on farms that have been affected by H5 and H7 avian influenza viruses, regardless of how pathogenic these viruses may be to poultry?
Liou Pei-pai is a former director of the Taiwan Animal Health Research Institute.
Translated by Drew Cameron