Improving our understanding of the risks of an LSD incursion

Lumpy skin disease (LSD) is not present in Australia but is a growing threat to the country's cattle and buffalo herds due to its presence and spread in Southeast Asia. To better understand the risk of LSD to Australia, epidemiological modelling was commissioned under a hypothetical scenario where LSD has spread and is endemic throughout South-East Asia, Timor-Leste and Papua New Guinea. The pathways examined pathways for potential incursions, included windborne insects and infectious insects hitchhiking on commercial vessels or returning live export vessels.  

While the probability of LSD entering Australia was estimated to be lower than previously thought, the parameters used in the modelling are subject to considerable uncertainty and limitations. The modelling helps to target research and mitigate the risk of LSD arriving and spreading in Australia, but there are still many global knowledge gaps about LSD.  

Key findings from the modelling work are: 

• there is strong scientific evidence that a single insect is unlikely to start an incursion of LSD. Instead, it is very likely that several insects must land on a single animal to begin an infection. This is hard to achieve when insects are blown across several hundred kilometres, so it becomes a sensitive parameter in the epidemiological assessment. 
• LSDV was restricted to Sumatra and Central Java province as of October 2022. Atmospheric modelling suggests windborne dispersal of insects to Australia from these regions is very unlikely. However, it was anticipated that LSDV will continue to move eastwards. Since the modelling was done, LSD has now been reported in East Java, which is closer to Australia, and windborne dispersal is possible from this region.  

The modelling work helps Australia plan for possible outbreaks of LSD by identifying where and when to look for the virus, and which group of insects to focus on. Mosquitoes present a higher risk of transmitting the virus, and the Tiwi Islands and regions east of Darwin to the Cobourg Peninsula are most at risk of windborne incursion. However, there are key knowledge gaps around the virus and its transmission, such as how many insects are required to transmit the disease. The risk assessment model helps to identify the most uncertain and highest risk steps in the hypothetical spread pathway, which can inform priorities for further work. 

New information from this recent work provides critical insights to further support preparedness and target efforts. Under the National LSD Action Plan and Northern Australian Biosecurity Strategy, work on key research gaps and assumptions has already commenced.  

For detailed information click here. The reports associated with this work can be found in the download section.