Newcastle Disease

Editorial Information

Newcastle Disease is one of two notifiable diseases of game birds in the United Kingdom, the other being Avian Influenza. Newcastle Disease is caused by a Paramyxovirus Type 1.

The disease was first reported in the UK in 1963 in pheasants. The severity of the disease depends on the virus strain, the species affected, the immune status and age and condition of the bird. These different strains can affect different organs of the bird with varying severity - mortality in some cases can be as high as 90%.

Newcastle disease virus is highly contagious and is spread via infected droppings and respiratory discharge between birds. Spread between farms is by infected equipment, trucks, personnel, wild birds or windborne - though this is less of a risk. The incubation period is variable but usually about 3 to 6 days.

If Newcastle Disease is suspected, DEFRA should be contacted as soon as possible.

Clinical Signs

Unfortunately, there are no classical clinical signs for diagnosis of Newcastle Disease. Newcastle Disease affects the respiratory, nervous and digestive systems and therefore can display a wide range of symptoms. Diarrhoea, neurological signs (Such as nervousness, depression, muscular tremors, drooping wings, twisting of head and neck, circling and complete paralysis), acute death, respiratory disease and egg drops often with peritonitis in laying birds can occur. All, or a combination, or just one of these may be present. Swelling of the neck and face may also be noted. In young birds, nervous signs with sudden high mortality are most likely to be seen.

Fig 1 Greenish diarrhoea which can be a sign of Newcastle Disease

Post Mortem Findings

A post mortem will typically find air sac culitis, tracheitis, visceral intestinal lesions as well as caecal lesions. Haemorrhages can occur in the internal tissues.

Fig 2 Inflammation of the lining of the windpipe

Fig 3 Haemorrhage in to the lining of the proventriculus (stomach)

Fig 4 Inflammation and haemorrhage of the caecal tonsils

Diagnosis

Diagnosis cannot be done on clinical signs or post mortem alone. Absolute diagnosis is by blood sampling or virus isolation.

Treatment and Control

There is no known treatment for Newcastle Disease.

Currently, there is no Newcastle Disease in the UK, but it can be introduced by migrating birds or the import of infected birds, as has happened in previous years. You should always check the provenance of any birds you purchase and request certification for imported birds. Maintain all records of purchases and sales, and isolate all new birds for 30 days if possible.

If Newcastle disease is suspected then APHA must be informed either directly or via your private veterinary surgeon.