CANBERRA, Australia: Australian quarantine authorities on Thursday urged travellers through Asia to avoid bringing in hitchhiking amphibians after a passenger arrived at an airport with a dead Indonesian toad in his shoe.

The Department of Agriculture of Water Resources warned travellers to check their luggage and other belongings for biohazards after toads from Thailand and Indonesia were found recently at three Australian airports. Authorities are confident that all the passengers were unaware they were carrying toads and were not smuggling wildlife.

The department’s head of biosecurity Lyn O’Connor said a sniffer dog reacted to a shoe that an Australian was wearing as he arrived at Cairns Airport in northeast Australia.

The black-spined toad found by a biosecurity officer inside the shoe had only recently died and was probably alive when the passenger put the shoe on in Indonesia, O’Connor said in a statement.

A live banded bullfrog was found in a passenger’s shoe at Perth Airport on Australia’s west coast after a flight from Thailand, the department said. Officials could not immediately say on Thursday whether the passenger was wearing the shoe or had packed it in luggage.

A live black-spined toad arrived on a flight from Thailand at Melbourne Airport in southeast Australia where it was found in a woman’s luggage, the department said.

The black-spined toad could significantly damage the Australian environment and could carry exotic parasites or disease, O’Connor said.

Australia has some of the world’s toughest quarantine regulations in a bid to keep pests and diseases from infiltrating its isolated borders and destroying the country’s unique wildlife. The strict quarantine policies captured global attention in 2015, when Johnny Depp and his then-wife, Amber Heard, were charged with illegally bringing their pet Yorkshire terriers into Australia, where Depp was working on a movie.

They subsequently made an awkward apology video that warned others about violating the quarantine rules and avoided jail.

— AP