Netherlands 19 May 2011 - The veterinary authority has confirmed that the avian influenza A virus that affected a flock of free-range hens in Gelderland is the low-pathogenic H7N7 sub-type. Screening has been carried out on all poultry in a three-kilometre zone. Serotype is H7N7.
Serotype is H7N7. So far, 56 nearby holdings have been clinically inspected and sampled for PCR and serological examination, and all samples have tested negative.
Avian Influenza
Avian Influenza is a highly infectious disease affecting many species of birds, including commercial, wild and pet birds. It may also affect people and other animals in certain circumstances. It is caused by a Type A Influenza virus.
Avian Influenza viruses can be classified according to their ability to cause severe disease (pathogenicity) as either highly pathogenic or low pathogenic. Highly Pathogenic Avian Influenza viruses (HPAI) can cause severe disease in susceptible birds. Low Pathogenic Avian Influenza viruses (LPAI) generally cause mild disease or no disease at all. Avian Influenza is one of the most important poultry diseases, and serious outbreaks of disease have been reported in many countries.
The severity of the disease depends upon the strain of virus and the type of bird infected. Birds infected with HPAI may die suddenly or show a range of clinical signs including respiratory signs, swollen heads, dullness, a drop in egg production, and a loss of appetite. Some birds, especially waterfowl, can be infected with LPAI without showing any signs of disease.
Avian Influenza is spread by movement of infected birds or contact with their secretions, particularly faeces, either directly or through contaminated objects, clothes or vehicles.
Why is there so much concern over an outbreak of Avian Influenza?
There is concern that the virus may change (re-assort or mutate) to emerge as a new virus that is easily transmissible between people and capable of causing disease in people, birds and other animals. Influenza A viruses occur worldwide in man and a wide range of mammals.
The highly pathogenic H5N1 Avian Influenza strain involved in most of the Asian outbreaks during the 2007-2008 has shown the ability to jump the species barrier occasionally and cause severe disease, with high mortality, in humans. However, it has not shown the ability to move easily between humans.
Avian and Human Influenza viruses can exchange genetic material when a person or other animal susceptible to infection with both viruses is simultaneously infected with both viruses. This could create a completely new subtype of the Influenza virus to which few, if any, humans would have immunity and which might be able to spread between humans.
More information on the risks of this happening and the implications are held on the World Health Organisation (WHO) and Health Protection Agency (HPA) websites.
Please contact Holchem Technical Centre for more information.