Experts say more research is needed to understand the potential role Australia’s large feral pig population could play in the spread of a disease such as foot-and-mouth disease if an outbreak occurs here.
Feral pigs are already causing massive damage to crops, livestock and other agricultural sectors across Australia on a large scale, costing the economy at least $100 million every year.
They can also be potential disease carriers.
In many parts of the world, wild or feral pigs have been shown to be involved in the spread of African swine fever. In 2019, African swine fever was detected in Timor Leste and then in Papua New Guinea in 2020.
These events contributed to the many reasons why a National action plan for feral pigs was created in 2020 and launched in 2021.
The risk cannot be ruled out
Existing research suggests that feral pigs are unlikely to play a significant role in the epidemiology of foot-and-mouth disease in Australia, national feral pig management co-ordinator Dr Heather Channon told Beef Central in response to questions. of Beef Central.
Climatic conditions, the ability of the virus to survive outside the host for long periods of time, and the density and size of feral pig populations make it unlikely that they are involved in maintaining a reservoir of FMD infection.
However, they are still a potential risk that cannot be completely ruled out, according to Dr. Channon.
What the research says
A 2011 study by Mohammad et al showed that under experimental conditions, serotype A could be transmitted from domestic pigs to feral pigs and vice versa. A study published by the European Food Safety Authority in 2012 concluded that transmission from wildlife to domestic animals can occur, so wildlife may play a role in the spread of foot and mouth disease.
However, Dr Channon points out that experimental evidence does not prove the potential for virus transmission when disease prevalence and proximity to infected animals may be much lower in a natural setting.
Australia’s AUSVETPLAN says that for foot-and-mouth disease, one of the most contagious animal diseases, the movement of infected animals is one of the most important routes of spread between herds and farms. Transmission occurs most easily when animals are in close proximity, such as at watering and feeding points, and at assembly points such as stockyards and milking barns.
AUSVETPLAN cites evidence to show that experience to date with FMD in tropical countries suggests that spread from cattle and buffaloes to pigs through casual contact is rare.
European studies show that while the infection can spread to wild boars, wild animal populations are not able to sustain the infection.
Deer, for example, do not appear to influence the spread of foot and mouth disease in wildlife. Studies of South American outbreaks show that feral pigs played no role in spreading the disease.
Potential of feral pigs to spread disease in Australia
As a result, said Dr Channon, the potential for feral pigs in Australia to spread foot-and-mouth disease will depend on factors such as host abundance, contact rates, habitat suitability and climatic factors. . “
With the National Feral Hog Action Plan now in place, we aim to achieve lasting reductions in the impact of feral hogs by helping land managers apply combinations of humane management techniques and best practices to control effectively feral pig populations and reduce their impacts,” said Dr Channon. .
“It means encouraging people to work together (rather than individually) and providing the tools, technologies, resources and training needed to support their actions on the ground.
She added that the entry, spread and maintenance of FMD in wild animal populations will be subject to continuous risk assessment to ensure wild animals are fully considered in the design of the control program. ‘eradication.
Risk mitigation programs will be implemented in wildlife populations that are assessed to pose unacceptable risk. The assessment will require information on:
- density and distribution of animals
- social organization, including home ranges
- contact with domestic species
- FMDV strain
- how long wild animals could have been exposed to the virus
- potential exposure of wildlife to risk materials, such as in landfills, in pens sprayed with milk, or in areas used for composting.
This information will make it possible to determine the level of measures to be applied, in particular:
- tracing and monitoring
- population reduction
- restrictions placed on hunters so that feral pig populations are not further dispersed.
In Indonesia today, the rapid spread of foot-and-mouth disease is most likely associated with the movement and trade of infected farm animals, Dr Channon said.
The re-emergence of foot-and-mouth disease in Indonesia has required Australian land managers to be vigilant with on-farm biosecurity practices, be on the lookout for signs of foot-and-mouth disease, and contact the national FMD emergency hotline. Animal Disease Watch on 1800 675 888 to report any animal behaving abnormally, or showing symptoms of foot and mouth disease.