Newcastle disease

Newcastle disease is a notifiable disease

Under Queensland legislation, if you suspect the presence of this disease in domestic poultry you must report it to Biosecurity Queensland on 13 25 23 or contact the Emergency Disease Watch Hotline on 1800 675 888.

Overview

Cause Newcastle disease is caused by a virus of the family Paramyxoviridae.
Description

Newcastle disease (ND) is a highly contagious viral disease of domestic poultry, cage and aviary birds, and wild birds. The disease is a serious economic threat to the poultry industry in Australia.

ND viruses have varying capability (pathogenicity) to produce clinical disease in domestic chickens, with some virus strains showing high levels of pathogenicity while other strains produce no disease and are classified as nonpathogenic (avirulent).

Where the disease occurs Strains of the virus are present in most countries. The severe form of the disease occurred in Australia in the 1930s and in 1998, 1999 and 2002.
The disease in animals

ND is usually seen in domestic poultry as a rapidly fatal, high-mortality condition characterised by gastrointestinal, respiratory and/or nervous signs. In other avian species, the disease produced by virulent ND viruses ranges clinically from inapparent to a rapidly fatal condition.

The severity of the symptoms depends on the strain of the virus and the age and health of the bird. The incubation period is usually 5 to 6 days but may vary from 2 to 15 days. The ND virus produces four broad clinical syndromes:

Viscerotropic velogenic ND: Appears suddenly and spreads rapidly. Symptoms are marked depression, loss of appetite, sharp drop in egg production, increased respiration, swollen heads, blue combs, and, often, a profuse green diarrhoea that leads to dehydration and collapse. Birds may die within two days. Birds that survive the initial phase often develop nervous signs such as twisted necks and muscle twitching. Up to 90% of birds may die.

Neurotropic velogenic ND: Severe respiratory and nervous signs predominate, including coughing and gasping, head tremors, wing and leg paralysis and twisted necks. Depression, loss of appetite and a drop in egg production also occur. Between 10% and 20% of adults and a larger proportion of younger birds may die.

Mesogenic ND: Mainly respiratory signs, with coughing but no gasping. Other signs include depression, loss of weight and decrease in egg quality and production for up to three weeks. Nervous signs may develop late in the course of the disease and death rates are about 10%.

Lentogenic ND: Symptoms are mild or absent and include mild respiratory signs, impaired appetite and a drop in egg production. No nervous signs occur and deaths are usually negligible.

How the disease spreads ND spreads easily by contact with infected or diseased birds. The virus is excreted in manure and is expired into the air. Other sources of infection are contaminated equipment, carcasses, water, food and clothing.
Control of the disease in animals

The emergence of Australian-origin ND viruses by mutation from lentogenic strains caused a rethink of the control of the disease in Australia. A vaccination program was introduced to protect commercial flocks against these strains. From 1 April 2005, vaccination of chickens in commercial flocks in Queensland has been compulsory under the Stock Regulation 1988. The National Newcastle Disease Management Plan outlines requirements for Queensland producers.

Exotic strains of virulent ND virus detected in Australia will be eradicated by immediate quarantine of the flock and the elimination of the virus by stamping out, disinfection of premises, and movement controls.

Can people get the disease? A mild form of disease can affect people, causing headaches, flu-like symptoms and conjunctivitis.

Vaccination program

  • Vaccination of commercial poultry flocks for Newcastle disease is compulsory and must be carried out according to the National Newcastle Disease Management Plan

Further information

Last updated 31 January 2012