Australia’s first outbreak of a highly pathogenic bird flu virus in 15 years should be contained by a cull of 50,000 chickens, authorities said on Friday, although they do not know what caused the case at an egg farm in New South Wales state.

The Department of Primary Industries (DPI) said all chickens at the property in Maitland, 160 km (100 miles) north of Sydney, will be destroyed after the H7 virus was detected last week.

The H7 strain is highly pathogenic to birds but is not related to the H5N1 strain, which was first detected in 1997 in Hong Kong and has since caused hundreds of human deaths.

DPI Chief Veterinary Officer Ian Roth said the strain did not present any risks to food safety from poultry and eggs.

The owners of the infected farm have been quarantined as experts try to find the source of the virus, often wild birds.

“It generally spreads by the movement of birds from the farm and there certainly hasn’t been any of those,” Roth told Australian Broadcasting Corporation radio.

“We’re in the process now of doing the tracing and also surveillance in the area, and so far the tracing looks quite good. There hasn’t been much potential for spread,” he said.

Australia’s agriculture ministry reported the outbreak to the Paris-based animal health body OIE on Thursday.

Australia’s Chicken Meat Federation said the industry produced around 1.12 million tonnes a year, worth around A$1.9 billion, with most used domestically and only around 5 percent exported.

JAPAN BANS IMPORTS

Japan banned the import of poultry and eggs from Australia after the outbreak, the country’s Ministry of Agriculture said in a statement late on Thursday.

Japan imported 0.9 tonnes of meat in 2011 and 1.9 tonnes in the two years before. Imports of eggs totaled 2.1 tonnes in the three years through last year. Japan is asking Australian authorities to provide more details about the outbreak, the statement said.

Chicken Meat Federation executive director Andreas Dubs said most exports were for pet food, while chicken feet were exported to some countries where they are eaten by humans.

The Australian government’s official commodities forecaster expects about 41,000 tonnes of chicken to be exported in the financial year to June 30, 2013.