Over the last two years, our vet and biosecurity teams have been working on a project that is a little different to what they usually do.
The teams set out to determine the risk posed by feral pigs to human and livestock health through the collection of samples from trapped feral pigs, as part of routine pest management activities. The collected samples were tested to see if the pigs had been exposed to the diseases brucellosis and leptospirosis. Both diseases are zoonotic, which means they can be transmitted to humans.
Brucellosis in pigs is caused by bacteria called Brucella suis. It can be transmitted to dogs or humans though contact with body fluids and causes fever, lethargy and abortions in both species. Research has shown a prevalence of around 3% in feral pigs in northern NSW.
Leptospirosis is caused by one of many serovars (types) of the bacteria Leptospira. It can affect many species, including cattle and humans, causing fever/flu like signs in both species. In cattle, it can cause abor-tions and severe organ damage. In hu-mans it can, in some cases, cause severe disease.
The project is continuing, but we have released some early results.
So far we have tested over 200 pigs. Of these, none had evidence of exposure to Brucellosis. However, 25% of the feral pigs had been exposed to at least one Leptospira serovar and 7% of them were actively shedding Leptospira bacteria at the time they were sampled.
This information allows us to shed some light on our original question. In our area, at this time, our findings suggest there is a very low risk of humans contracting Brucellosis via exposure to feral pigs. The risk of coming into contact with Leptospira bacteria appears to be a lot higher.
To reduce the risk of Leptospirosis in cattle, a vaccine is available. Usually referred to as a “7in1”, the product covers the same clostridial diseases as a “5in1” (such as tetanus and blackleg) plus two Leptospira serovars – Hardjo and Pomona.
If you come into contact with feral pigs through work or recreation, it is important to take precautions to reduce the risk of transmission of Leptospira bacteria. NSW health recommends strict precautions are taken for people who work with animals. These can be found online: www.lls.nsw.gov.au/news-and-events/news/ct-news/2021/feral-pig-sampling.
If you have questions about these diseases in livestock or feral animals, please contact your local District Veterinarian. If you have concerns about human health, please contact your GP.
By Dr Jess Bourke
District Veterinarian – Local Land Services