pregnant woman living in Queensland, Australia has tested positive for the Zika virus, say health authorities.

overseas trip, said Queensland Health, but gave no further details. She was diagnosed on Tuesday.

It is Australia's third case of Zika, following two people in Queensland who also caught it abroad.

Zika has been linked to a condition called microcephaly, in which babies are born with underdeveloped brains.

An international health emergency has been declared by the World Health Organization over the virus, which has spread rapidly in South and Central America, as well as the Caribbean.