Australia battling to contain prawn disease outbreak

Australia is battling to contain a biosecurity threat in farmed prawns after a fifth farm was tested positive for White Spot Disease in the Logan River.

The Logan River, just south of Brisbane in Queensland state has been closed to all commercial and recreational take of shellfish since early December while biosecurity authorities respond to the diseases outbreak after tests confirmed presence in local prawn farms.

Authorities however have confirmed the disease is present in a fifth prawn farm, 5 km downriver from another four that have been destocked following positive test results, local media reported Tuesday.

"At this stage it is not yet clear how the virus has come to be present on this premises," Biosecurity Queensland said in a statement.

"There are three other aquaculture premises in the immediate vicinity, but one of these currently has no prawn stock."

Infected crustaceans do not pose a health risk to humans, however the disease does cause high mortality rates in farmed and wild stocks. Farmed prawn production typically drops to 40 percent of normal levels for two years, before recovering to approximately 70 percent over the long term.

Testing is continuing in the surrounding waterways to ascertain the spread of the disease while investigating its source. The disease can persist and retain infectivity in the water column for four to seven days.

Australia was previously considered free of the virus which has decimated farmed prawn stocks in Asia. Local officials contend the disease has not established itself in wild crustacean populations. Enditem