The chief veterinary officer has spelt out why authorities believe the cases of lumpy skin disease in cattle shipped out of northern Australia occurred on Indonesia soil.
The positive tests have led to Indonesia suspending four northern Australian quarantine yards from supplying cattle to its market until Australia can provide tests confirming it is LSD-free.
The incubation period for LSD is between 5 and 15 days post-infection, Dr Schipp explained.
"This is why Indonesia is pointing to the results and saying that number of days ago those animals were in Australia," he said.
However, the testing methodology is sensitive to the extent it will detect animals that are in the early stages of infection or responding to a vaccination.
"So if these animals were infected en route as they approached Indonesia, as they were being unloaded, during the eight hours of trucking to feedlots or in the period they were held at feedlots before tested, it is possible they would respond to the tests before clinical signs were seen," Dr Schipp said.
"As a consequence we believe this is a response to an infection in Indonesia rather than an infection in Australia."
Further, it was difficult to distinguish clinically between vaccination and an infection, Dr Schipp said.
"It is possible that vaccinated animals test positive because an attenuated form of the virus is present in the vaccine," Dr Schipp said.
"This is one of the challenges of this disease - the vaccines use a live attenuated virus. That was one of the reasons we sought permission to bring the virus and vaccine into our CSIRO facility at Geelong so we could look at the purity of the vaccine and its efficacy."
Australia will not vaccinate as a precaution because it would no longer be able to claim to be free of the disease in accordance with the World Organisation for Animal Health requirements, which would significantly impact access to export markets.
Vaccinating on the water was also highly problematic, government officials said.
Thus, the animals are vaccinated as soon as they arrive in Indonesia.
Shan Goodwin
Shan Goodwin steers ACM’s national coverage of the beef industry. Shan has worked as a journalist for 30 years, the majority of that with agricultural publications. She spent many years as The Land’s North Coast reporter and has visited beef properties and stations throughout the country and overseas. She treats all breeds equally. Contact 0427686187. E: s.goodwin@austcommunitymedia.com.au
Shan Goodwin steers ACM’s national coverage of the beef industry. Shan has worked as a journalist for 30 years, the majority of that with agricultural publications. She spent many years as The Land’s North Coast reporter and has visited beef properties and stations throughout the country and overseas. She treats all breeds equally. Contact 0427686187. E: s.goodwin@austcommunitymedia.com.au
