''A new infectious disease is reported somewhere in the world every eight months and most come from animals,'' Professor Brownlie said.

''So veterinarians play a key role in combating new diseases particularly in the surveillance, detection and response to animal disease outbreaks.

''Making sure we're fully equipped to deal with a new, unexpected disease is a global concern.''

Professor Brownlie, of London's Royal Veterinary College, arrived in Canberra yesterday to attend the Australian Veterinary Association's national conference which begins today.

He will open the week-long conference with a speech about the nature of disease spread.

''Geographical barriers that previously prevented the spread of infection are no longer in place as people travel around the world with greater speed and in greater numbers,'' he said.

''To provide for the demands of a rapidly growing population we are also seeing a worldwide increase in imports and exports, including animals which provides another avenue for the transfer of diseases.''

Professor Brownlie said Australian vets had already contributed substantially to the world's understanding of animal diseases.

''In Australia, veterinarians have been instrumental in recognising, identifying and combating previously unknown infectious diseases such as Australian bat lyssavirus, Menangle virus and Hendra virus.

''All these diseases originated in animals and have transferred to humans sometimes with fatal consequences.''