Newcastle Disease (ND)
Declare it for Australia
(ASNSW Avicultural Review - Vol 8 - No 9 September 1986)
(Printable Version - PDF file - Free Adobe Reader download)
by Peter Gray B.V.Sc.
When Harry Butler sits on a log patting a cuddly Australian and talking about protecting Australia from killer diseases, is it just a publicity stunt? Or, as the Department of Quarantine destroy Australian bird collections that have taken years to build, is it just a way of flexing bureaucratic muscle that has gone flabby from lack of exercise?
To try and answer these questions in part, let's take a look at one disease which is very important for bird keepers throughout Australia. It is a disease that has nothing to do with coal mines or steelworks, but is called NEWCASTLE DISEASE, after the place in England where it was first identified in 1927. So what is it? It is a highly fatal infectious disease of birds, especially poultry, caused by a virus which survives for long periods of time in the environment. A mild form exists in Australia, but the severe form has not yet seen the Paul Hogan advertisements and is not here – as far as we know!!
All birds are susceptible to the virus but for some reason, parrots seem more resistant than other species.
NB: Viral Disease / Worldwide / Killer / All Birds.
There are two important things to know about Newcastle Disease:
- The virus that causes Newcastle Disease has different forms or strains, each affecting birds of different species in different ways. That is, one strain of Newcastle Disease virus that has no effect on pigeons, may kill finches.
- If a bird that is unaffected or only mildly affected by a certain strain of Newcastle Disease virus comes into contact with the virus, it may pick it up and carry the virus in its system without showing any signs - this is the carrier state.
NB: Different Virus Strains / Carrier State.
The carrier state is the most important part of this disease.
What does it cause? This depends upon the strain of virus, but commonly there is depression, diarrhoea, respiratory signs leading to nervous signs, i.e. tremors, paralysis, muscle twitching and death. If the killer strain hits, birds fall like the proverbial flies.
Outbreaks of the killer strain have occurred in all birds, but finches, pigeons and especially poultry, are much more susceptible to Newcastle Disease.
The disease can be diagnosed from tissues of a dead bird and blood can be analysed from live birds.
There is no treatment for Newcastle Disease.
Just imagine this story: Mr X decides to bring a bird from overseas into Australia, but because of the fact that foreign birds cannot be brought into this country legally, he thinks of another way.
In all fairness to Mr X, the bird (more often birds) does not look sick, in fact they may look very healthy, but he's never heard of or forgotten or pushed to the back of his mind - the CARRIER STATE. So the bird is smuggled into Australia, more often than not, under very stressful conditions. If the bird is a carrier then due to stress, there's a good chance that it will pass the disease onto all birds that it contacts, or since the virus can be carried by the wind, it may pass onto any birds within a 3-4 mile radius. This will include wild birds, poultry or other cage birds - even pets.
Very soon, the killer strain starts working and spreads quickly - just like one spark can set off a raging bush fire.
Hopefully it will be diagnosed quickly and prompt action must take place. If not, the disease will escalate rapidly. ALL BIRDS (poultry, aviary, wild and pet birds) on that property and adjoining properties will be slaughtered promptly, with all questions being asked later. Then all birds within a 50km radius will be tested. All bird movements are traced and the movement of all people to and from that property over the past few months is investigated.
It's important to remember that there is no treatment and if prompt and severe action is not taken, it could mean the end of a rapidly growing Australian poultry and aviary industry.
What Can We Do About It?
There's no doubt that smuggling of birds into Australia is not uncommon and even if legal importing becomes a reality the chances are that smuggling will continue. It will only take one bird, one carrier, to spread Newcastle Disease.
However, this article was not written to promote panic, but to make everyone aware of the dangers of Newcastle Disease. It should make the poultry industry, aviculturists, vets, officers of the Department of Agriculture and Quarantine look at how they can work together, because an outbreak of Newcastle Disease will not affect the 'other bloke' but may well affect us all with devastating results.