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Issue 52 | May 2009
Poultry disease researcher,
Anthony Keyburn.
Photo by Frank Filippi, CSIRO
Working at CSIRO's Australian Animal Health Laboratory (AAHL) in Geelong, Monash University PhD student, Anthony Keyburn, has made a discovery which will change the focus of the worldwide search for a vaccine for the major poultry disease – necrotic enteritis.
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Listen to the podcast [Windows Media audio 3m:54s] |
Poultry producers use antibiotics to treat and prevent the disease which, when triggered, can cause mortality rates of up to 50 per cent and costs the world's poultry producers an estimated US$2 billion every year.
Mr Keyburn and a team of Australian scientists have found alpha-toxin protein – long thought to be required for necrotic enteritis to develop – is not the main cause of the disease.
In this podcast Mr Keyburn explains how the team's work will benefit future research into the development of an effective vaccine.
Welcome to CSIROpod, I'm Bill Stephens.
Monash University PHD student working at CSIRO's Australian Animal Health Laboratory, or AAHL, in Geelong, has made a discovery which should radically change current approaches to finding what causes a major poultry disease – necrotic enteritis. A bacterial disease which affects poultry producers worldwide and can cause death rates of up to fifty per cent, necrotic enteritis is caused by a bacterium – Clostridium perfringens – which is found in small quantities in the guts of healthy chickens.
The disease is only triggered when the bacteria proliferates to high numbers and produces toxins which attack the birds intestines. Until now, the main culprit in that process was thought to be what is known as alpha-toxin.
However, with funding from the CRC for the Australian Poultry Industry, PhD student Anthony Keyburn and a team of scientists at AAHL recently revealed that the development of the disease is not dependant on the production of this kind of toxin.
Mr Keyburn joins us now. Anthony, welcome. Firstly, just how widespread is this disease?
Well, Bill, it's in all poultry producing countries worldwide. Australia hasn't got that large a problem with the disease currently, due to our good hygiene practices and antibiotic use within the industry. However, America and Europe are showing increase in the disease at the moment. So it's becoming a bigger problem overseas and we are currently expecting it to become a larger problem in Australia in the coming years.
Why a larger problem in Australia?
Well there's a global shift towards the reduction of antibiotics within the industry. Back in 2000, even before, European Union has led the charge in reducing its use in antibiotics and since that time there's been a dramatic increase in the incidence of necrotic enteritis in the European Union. So, currently there is no effective vaccine in the market, so without the use of antibiotics there is no way of actually controlling the disease.
Now, you've discovered that alpha-toxin isn't the cause, so what is?
We've found this new toxin that the bacteria produce, we've called it netB because it has similarities to another toxin that the bacteria can produce, but is not associated with necro enteritis so it's a new toxin, we've found in most of the poultry bacterial strains that we have screened so far and by genetically modifying the bacteria so it no longer produces toxin we have found that those strains that no longer contain this toxin no longer cause disease in chickens.
It's a major discovery. How will it affect future research into the cause of the disease?
Well, before this research was done, alpha-toxin was believed to be the major virulence determinant so research into vaccine development has always been based on alpha-toxin. So this will create a shift in the way we try and develop vaccines against this devastating disease. Hopefully through this work we can get a vaccine out there within the next five or ten years.
So in Australia we're going to be rejigging the research task, is that right?
That's correct. Through this work that we've done here we're starting a new project looking at not only further developing vaccines that are based on the netB toxin but also trying to find other determinants that may help in future.
Thanks for that, Anthony.
I've been talking to Monash University PhD student, Anthony Keyburn.
To hear more CSIRO podcasts, go to www.csiro.au
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