A sixth mute swan, which was collected on January 21st as part of wild bird surveillance in Dorset, England, has tested positive for H5N1, the virulent bird flu virus strain, reports Defra (Department for the Environment Food and Rural Affairs). Defra added that this sixth confirmation is not a surprise.

Defra informs that the area is currently undergoing an “enhanced surveillance” of wild birds.

Authorities say that current evidence does not point in any way to a spreading of the current outbreak. Nevertheless, poultry keepers in the area have been asked to remain watchful and report any signs of disease at once.

The current outbreak only involves wild birds. No domestic birds have been infected, informs Defra. Samples taken from live swans in the area have all tested negative for H5N1 and other avian influenza virus strains.

As of 3pm on 25 January, the limits imposed on the movement of poultry or other captive birds in the Wild Bird Monitoring Area were lifted, and such movements no longer require a license. Movement restrictions in the Wild Bird Control Area continue.

What is Bird Flu (Avian Influenza)>

Bird flu, or avian influenza, is a disease cause by viruses. It is a contagious disease which infects only birds, and sometimes pigs. The avian influenza viruses attack specific species – they have, on occasions jumped the species barrier and infected people. However, this has been quite rare, and continues to be rare (January 2008).

As far as farmed birds are concerned (poultry), there are two main types of avian influenza – one is fairly mild while the other is deadly (for birds).

Mild

Low pathogenic forms of bird flu may cause a bird to have more ruffled feathers and lay fewer eggs. This form is often undetected among farmed poultry (in many cases the bird is infected, and then gets better and nobody noticed).

Deadly

The highly pathogenic form of bird flu is much more dangerous. It has a mortality rate of virtually 100% and spreads very rapidly among flocks of birds. A bird infected with the more virulent type of bird flu (the highly pathogenic form) experiences deterioration of many internal organs.

The most dangerous strain of the bird flu virus is called H5N1.

Avian influenza (bird flu): Latest situation (Defra)

Written by – Christian Nordqvist