Lumpy skin disease is edging closer to Australian shores, with the highly contagious cattle disease confirmed in East Java.
The viral disease — which can spread via insects — was first found in Indonesia in March on the western island of Sumatra.
Bali-based vet Ross Ainsworth said cases of lumpy skin disease were now evident in Central Java and East Java, which brought it about 1,000 kilometres closer to Australian shores.
Indonesian disease reporting websites have also confirmed the spread.
"It demonstrates that the disease is heading in an eastward direction towards Timor where the real risk will come from the potential of insects flying across or being blown across the ocean to Northern Australia," Dr Ainsworth said.
If detected in Australia, it is estimated lumpy skin disease could cost Australia's agriculture sector $7 billion within its first year.
Bali could be next in line
Bali is now in close proximity to the disease as it moves east through Indonesia.
It comes after the recent spread of another damaging livestock infection — foot-and-mouth-disease — to the popular holiday island.
Its detection in July caused major concerns for the agriculture sector, with fears travellers would bring it back on their clothes, shoes or luggage.
But Dr Ainsworth said the spread of lumpy skin disease to Bali did not pose the same threat.
"It's not like foot and mouth where it's so easy to carry on humans and other inanimate objects," he said.
"They (Indonesians) have always had quite strict protocols for lots of other diseases to kill off any insects that make it onto the plane, so existing prior security arrangements are probably quite adequate.
"The risk is not that the people will take it with them back to Australia, the risk is … it's then that much closer to Timor where the distance across the ocean to Darwin is the least."
Disease never 'seriously studied'
While lumpy skin disease has been detected in various countries before, questions remain about how it is transmitted.
Dr Ainsworth said there was still much to learn about its spread via insects, which would help the cattle industry understand the risk of it spreading through monsoonal winds to Australia.
"We don't know exactly which insects carry it, we don't know how far they go," he said.
"It's never been seriously studied … so we need to know a lot more about this disease."
How it spread to East Java is also unknown, but it's hoped any further spread towards Bali could provide some answers.
"Some people are pretty confident that the spread throughout Java is by movement of animals themselves, or infected material from animals," Dr Ainsworth said.
"It is not permitted to bring cattle and buffalo into Bali from Java, so that will be a good test of the movement of the disease.
"If the disease gets here that will provide some sort of probable proof that the disease is transmitted to Bali through insects."
