SPECIAL NOTICE: NEWCASTLE DISEASE
This information on Avian Influenza, also known as ‘bird flu’, is taken from the Queensland Department Agriculture,
Fisheries and Forestry website. Check their website for the latest information on this important topic
Newcastle disease (ND) 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.
Some strains of the disease cause only minor symptoms while others are fatal. Other diseases with similar symptoms
include: Avian influenza: Infectious laryngotracheitis (ILT): Infectious bronchitis: Marek’s disease: Pasteurellosis
(cholera)
ND poses no public health risk to consumers of eggs or poultry products.
Vaccination of commercial flocks for ND is compulsory and must be carried out according to the Newcastle disease
vaccination program, Queensland.
Symptoms
Susceptible
species
Infection
and spread
Distribution
Persistence
Significance
Human
health
Control
Other
diseases
with similar
symptoms
include:
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 2-15 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 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 large 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.
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.
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.
Present in most countries. Severe form of ND occurred in Australia in the 1930s and in 1998, 1999 and
2002.
The virus is readily destroyed by heat, soaps and detergents, hypochlorites, alkalis, gluteraldehyde or
Virkon®. 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.
The virus is a serious economic threat to the poultry industry.
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.
From 1 April 2005, vaccination of chickens in commercial flocks is compulsory under part 8A of the
Stock Regulation 1988 (Qld).
Avian influenza
Infectious laryngotracheitis (ILT)
Infectious bronchitis
Marek’s disease
Pasteurellosis (cholera)
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Queensland Schools Animal Ethics Committee
Email: Animal.ethics@dete.qld.gov.au
Website: www.education.qld.gov.au/curriculum/area/science/animal-ethics.html