Whirling Disease is a chronic, debilitating wasting disease caused by Myxobolus cerebralis, a protozoan parasite. While the intermediate host of the parasite, a tubifex worm, is present in Australia, the parasite has never been detected in this country. It is however present in New Zealand where the bulk of salmonid imports into this country currently originate from. It is difficult to detect in imported fish. Infective spores can survive for considerable periods in fresh and frozen fillets.
Overseas it is a disease of salmonids; non salmonids have also been reported to be hosts.
There is a significant population of salmonids in Australia that would be susceptible to this disease were an outbreak to occur. These populations are valuable both commercially and recreationally.
It is extremely important to have in place options for dealing with an outbreak of the disease to minimize the impact of such an outbreak should it occur. It is also highly beneficial that such options have been considered and agreed to by relevant stakeholders before the emergency occurs. Such options would acknowledge this disease may be insidious in its onset so may go undetected for a long time. Spores can also survive the passage through the gut of birds.
While the Federal Government encourages a detection and eradication culture based on constant vigilance and a readiness to tackle any emergency, there are currently no accepted national guidelines for dealing with an outbreak of an exotic parasitic disease in finfish in Australia.
Hence there is a need to have a Disease Strategy Manual for Whirling Disease that describes details about the disease, response options and the preferred, nationally agreed-upon approach to its control. This is supported by the FRDC’s Subprogram’s Steering Committee who, through consultation with stakeholders from industry and governments have determined as a priority the need for this Manual.