The Department of Agriculture and Water Resources is aware of media reports today about white spot disease in Australia.
The department has progressively implemented conditions to effectively minimise the biosecurity risk associated with imported prawns since 1992.
Based on information that the level of risk associated with uncooked imported prawns had become unacceptable, the Director of Biosecurity suspended imports on 6 January 2017.
The department has an extensive product withdrawal program in place to deal with product already in the country.
White spot disease is a highly infectious disease of crustaceans but does not pose a threat to human health or food safety.
The source of the outbreak of white spot disease in south-east Queensland has not been determined. There are a number of possible pathways, such as contaminated imported feed, probiotics, contaminated equipment, overseas visitors, poor on-farm biosecurity practices, and brood stock, as well as imported uncooked prawns used as bait.
The virus which causes white spot disease is believed to be present at low levels in the environment in many wild prawn populations around the world.
The disease has been found in farmed populations in Asia, the Americas and Africa. Outbreaks of the disease in farmed populations in Madagascar, Mozambique and the Kingdom of Saudi Arabia have been most likely attributed to low level strains of the disease found in the local environment.
Good biosecurity practices should be observed at all times to prevent this disease transfer occurring.
There have been recent media reports of 100 wild prawns testing positive for white spot disease in the Logan River and Moreton Bay areas. These prawns are giant tiger prawns, which are of the same variety farmed in the prawn farms affected by this outbreak. Giant tiger prawns are not normally found in that environment, so it is a reasonable assumption that the prawns came from these farms and it may not indicate that the disease itself is present in the wild population in the river.
Based on the findings of previous compliance activity, the department commenced an investigation in mid-2016.
In 2014 the reported rate of rejected consignments of imported uncooked prawns following positive results for white spot was 4 per cent. By the end of 2016, this had increased to 18 per cent.
The first phase of the investigation involved targeted sampling and testing of retail product imported by a number of importers suspected of non-compliance. Because of the nature of the targeted testing, it could reasonably be expected that the results would be significant – around 50 per cent of product was infected.
The department's investigation has, to date, seen one importer lose their approved arrangement and import permit and the department is in discussion with the CDPP for consideration of possible charges. Action against a number of other importers is being considered and is likely.
At that time, the use of imported uncooked prawns meant for human consumption as bait was thought to be reasonably low – product is clearly labelled for human consumption and not for use as bait.
During the latter stages of the same investigation, departmental investigators surveyed recreational fishers in the Logan River area during the holiday period just passed and found fishers using imported prawns meant for human consumption as bait.
The department collected and tested samples of the bait. The test results indicated that two of the prawns were positive for white spot disease.
Around the same time, the department collected samples of imported raw prawns available for sale in the area, and sent them for testing at AAHL – Australia's leading animal health laboratory.
The results showing a significant number of prawns were positive for white spot disease were received from AAHL in the first week of January.
Once a possible pathway involving uncooked imported prawns could be demonstrated, the department began work to suspend the trade. The suspension was announced on 6 January 2017.
Australia has obligations as a member of the World Trade Organization to allow trade where the science says it is safe to do so.
Retail withdrawal activity
To reduce the risk associated with product already in the country at the time of the suspension, the department is working closely with major retailers to withdraw infected product from the market.
Product imported by the specific importers under investigation is being withdrawn.
In addition, the department is operating a national program of sampling and testing at the retail level, in distribution centres and cold stores.
A number of samples have tested positive for white spot from this program of testing, and are being withdrawn, some before they are even sent to supermarkets.
The department is currently working through over 100 consignments of prawns which were already in transit to Australia when the suspension took effect.
These consignments are being subjected to an enhanced inspection and double testing regime at the border to ensure any product entering the country is free from white spot disease. The product will not be released until it has undergone double testing and is confirmed free from the disease.
Only a small portion of the consignments have completed testing – out of 21 batches which have so far completed double testing, only five have been cleared as free from the disease.
These numbers will initially be skewed towards results positive for white spot, as they are returned quicker than the negative results which require confirmation from a second lab.
Regardless, this prevalence is unacceptable and all consignments with batches that have failed testing are being exported.
Import risk analysis
Prior to 1992, there were no controls on imported uncooked prawns.
In 1992, the department first introduced the requirement for import permits for imported uncooked prawns.
In 1996, the department formally commenced the imported prawn import risk analysis.
Following an outbreak of white spot disease in Darwin in 2000, the department began introducing interim conditions for uncooked prawns.
A draft risk assessment was released for comment in 2000.
The risk assessment was finalised in 2009 and implemented in 2010.
The risk assessment sets a number of mitigation methods to manage the biosecurity risk of the disease to a very low level, including import permit requirements, border testing and end use restrictions.
Biosecurity is a shared responsibility and it's imperative that Australian industry and the community are aware of their obligations and act accordingly.