December 20, 2012
University of Sydney Ovine Johnes Disease (OJD) researcher Peter Windsor has defended the university’s findings and prompted growers to think about the ethics of imposing mandatory industry-wide vaccination on producers whose animals do not have the disease He has also called on sheep producers to ‘know their enemy’ and not dismiss the risks of OJD by comparing it to footrot or lice or Australia’s management approach to New Zealand’s . Professor Windsor – the university’s professor of livestock health and production – defended his OJD research at an online information session last night, where sheep producers were given a lesson in effectiveness of the OJD vaccine. Sheepmeat Council of Australia (SCA) and WoolProducers Australia (WPA) co-ordinated the webinar to increase the industry’s understanding of how the OJD vaccine works and its effectiveness. SCA chief executive Ron Cullen said while it was a trial to some extent, it could be an important communication tool in future. Both SCA and WPA have previously been criticised for attempts to communicate changes to the national OJD management program. Prof Windsor was one of the key speakers. His research was taken into account by the national OJD management committee and is the basis for which the program adopted a new management plan. Speaking before the webinar, Prof Windsor said in the move to derail the new national program, it had been suggested there were problems with the university’s research findings. He said the outcome of the research was clear – it pointed to the fact vaccinated sheep from an infected property would still shed bacteria and a national management program was needed. “If we don’t have a program like this, we are saying everyone has to vaccinate. And that’s $2.50/sheep imposition across the industry,” he said. “Now, is that acceptable to the sheep industry? Apparently there are big sections of the sheep industry who say it is. “But they’re not the people in the low prevalence zones, they are the people who are trading sheep into the low prevalence zones. And you have to question the ethics of that in my opinion.” He hoped producers would gain a better understanding of the difficulties of managing the disease and that it was a very real risk that should not be dismissed. He said OJD should not be compared with other diseases, like footrot, and should not be dismissed through “bland statements”. “It’s nothing to do with any of those other diseases. It’s a mycobacteria, it’s an intracellular organism that knows how to neutralise the immune responses of the cells they are designed to eradicate. It just sits in there and ultimately turns the gut of the animal into an incubator,” he said. “You will spread the disease if you allow vaccinates from infected properties to be traded into clean flocks.” Prof Windsor said there was no comparison between Australia’s approach to control and New Zealand’s – in which there was no management plan. He said it was naïve to suggest Australia should follow their approach – rather New Zealand and other countries were looking to Australia because of our leading position and experiences with the disease. “People have not been listening to the message we’ve sent for years. The vaccine is a great tool for controlling the mortalities in infected flocks but it’s not a great tool of decreasing the risk of spreading the disease from vaccinated sheep from infected properties. “That risk is real, you cannot dismiss it by saying you are used to dealing with risk. “This is a different risk where a small number of sheep get the disease they shed a large amount of bacteria. One infected sheep can shed enough bacteria to infect every sheep in Australia.” Prof Windsor said there were “lots of holes” in abattoir surveillance but it was useful to provide confidence that the disease, if it was there, was only present at low levels.