Avian influenza: The signs and symptoms

Avian influenza (AI) has been spreading across Europe, with the most recent cases being found on a 5,000-bird duck farm in France, and a 15,000-bird duck farm in the Netherlands.

Wild birds struck down with the disease have also been reported in 14 European countries since early November.

The highly contagious disease was found last week in wild birds on the coast of France, near Calais, just 30 miles from mainland Britain.

In response, free-range poultry keepers have been ordered to move stock indoors, or at least keep them separated from wild birds, as a precaution against AI.

See also: Bird flu now only 30 miles from Britain

Government chief vet Nigel Gibbens declared the whole of England should be treated as a prevention zone for the next 30 days, introducing enhanced biosecurity for poultry and captive birds.

With the season of bird migration expected to peak between December and January, it is important to be aware of the signs and symptoms of avian flu as well as the biosecurity measures recommended.

How to spot AI

There are two types of AI – high pathogenic and low pathogenic.

High-pathogenic AI (HPAI)

HPAI is the more serious type. It is often fatal in birds. The main clinical signs are:

  • Swollen head
  • Blue discolouration of neck and throat
  • Loss of appetite
  • Respiratory distress such as gaping beak, coughing, sneezing, gurgling, rattling
  • Diarrhoea
  • Fewer eggs laid
  • Increased mortality
  • Clinical signs can vary between species and some may show minimal clinical signs (ducks and geese).

Low-pathogenic AI (LPAI)

  • LPAI is usually less serious
  • It can cause mild breathing problems, but affected birds will not always show clear signs of infection
  • The severity of LPAI depends on the type of bird and whether it has any other illnesses.

Biosecurity measures

  • Government chief vet Nigel Gibbens has advised enhanced biosecurity in light of the risk of infection, including:
  • Cleaning and disinfecting clothing, footwear, equipment and vehicles before and after contact with poultry
  • Reducing the movement of people, vehicles or equipment to and from areas where poultry are kept to minimise contamination from manure, slurry and other products
  • Thoroughly cleaning and disinfecting housing at the end of a production cycle
  • Keeping fresh disinfectant at the right concentration at all points where people should use it, such as farm entrances and before entering poultry housing
  • Minimising direct and indirect contact between poultry and wild birds, including making sure all feed and water is not accessible to wild birds
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