Newcastle disease factsheet
Compulsory vaccination program
Vaccination of commercial flocks for Newcastle disease is compulsory and must be carried out according to the Newcastle disease vaccination program, Queensland.
Newcastle disease is a highly contagious disease that affects the digestive, respiratory and/or nervous systems of domestic poultry, cage and aviary birds, and wild birds. It is caused by a virus of the family Paramyxoviridae
Overview
Symptoms |
Some strains of the disease cause only minor symptoms while others are fatal. 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 5-6 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 2 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 3 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. |
Susceptible species |
All birds, both domestic and wild. Most susceptible are domestic chickens, turkeys, pigeons and parrots. Milder disease is seen in ducks, geese, pheasant, quails, guinea fowls and canaries. |
Infection and spread |
Easily spreads 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. |
Distribution |
Present in most countries. Severe form of the disease occurred in Australia in the 1930s and in 1998, 1999 and 2002. |
Persistence |
The virus is readily destroyed by heat, soaps and detergants, hypochlorites, alkalis, gluteraldehyde or VirkonŽ. The virus is destroyed by direct sunlight within 30 minutes, but in cool weather can continue to survive in manure and contaminated poultry sheds for many weeks. A minimum core temperature of 80°C for one minute destroys the virus in meat products. |
Significance |
The virus is a serious economic threat to the poultry industry. |
Human health |
No public health risk to consumers of eggs or poultry products. Mild conjunctivitis and flu-like symptoms have been reported in people working closely with infected birds. |
Control |
From 1 April 2005, vaccination of chickens in commercial flocks is compulsory under part 8A of the Stock Regulation 1988 . |
Other diseases with similar symptoms include: |
Avian influenza Infectious laryngotracheitis (ILT) Infectious bronchitis Marek's disease Pasteurellosis (cholera) |
More information:
Last updated 21 April 2006
