Protecting yourself against zoonotic diseases
By District Veterinarian Dr Sarah Maher, May 2020
Controlling pest animal populations is an essential part of maintaining on farm biosecurity and reducing grazing pressures and many producers are working hard to stay on top of invasive populations. When doing this there are a few zoonotic diseases we should keep at the forefront of our mind when doing so.
Zoonotic diseases are diseases which can be naturally transmitted from animals to humans and can be bacterial, viral or parasitic in nature. The following zoonotic diseases are relevant to producers, pig hunters and anyone who comes in contact with animals:
Leptospirosis is caused by a bacteria, in pigs and cattle it causes reproductive losses. The bacteria multiply in the kidneys and as such urine contains high amounts of infective bacteria.
To reduce your risk of Leptospirosis avoid contact with eyes, nose, mouth and where possible wear gloves. If gloves are not available make sure you cover any cuts and wash your hands and arms well after contact with pigs.
Brucellosis is caused by infection with a bacteria called brucella suis (not the same as the one that infects sheep). The extent of infection in the feral pig population in NSW is still relatively unknown. B.suis can be transmitted to humans through breaks in the skin which become infected with pig fluids such as blood, urine or birthing fluids. B.suis causes reproductive failure such as abortions in pigs, so you are unlikely to detect infected animals while undertaking feral pig control so protect yourself! Again cover cuts, avoid contact with pig fluids especially reproductive fluids.
Q-fever is a disease caused by a bacteria called Coxiella burnetii. The bacteria can be carried cattle, sheep, goats and pigs, it occurs at highest concentrations in birthing and uterine fluids. Q-fever spread when the bacteria become aerosolised - in the air and dust making it harder to reduce your exposure. This means to adequately reduce the risk you would need to wear a P2 mask (we all know how fun that is). Fear not though there is an excellent vaccine available and we encourage all producers to consider vaccination.
Swine Erysipelas caused by a bacteria Erysipelothrix rhusiopathiae and is most commonly seen in growing pigs, signs range from sudden death to fever and diamond shaped skin lesions. Erysipelas is zoonotic and can cause skin infection in humans when the bacteria comes in contact with broken skin. Again covering any cuts and wearing gloves will help reduce the risk of transmission.
Hydatid disease or Echinococcosis
Hydatid disease is caused by a tapeworm (Echinococcus granulosus) which infects dogs, foxes, dingoes. Hydatids are a parasite with dogs being the primary host and cattle, pigs, sheep act as intermediate hosts. Humans can only be infected when they consume hydatid eggs which are excreted in dog faeces. Human infection can easily be prevented by ensuring good hand hygiene. The life cycle of hydatid disease can be broken in several ways including not feeding raw meat (especially offal) to dogs, preventing access of dogs to dead stock, or if you are planning to continue to feed raw meat to your dog treat the dog with praziquantel regularly.
Toxoplasma gondii is a parasite carried by cats. Pregnant ewes can become infected with toxoplasma when they consume the parasite (usually due consuming cat faeces), T.gondii can cause reproductive losses in sheep. Toxoplasma can be harmful to pregnant women and the immunosuppressed. Gloves should be worn when handling aborted lambs, and good hand hygiene adopted when cleaning cat litters, additionally fruits and vegetables should be washed before consumed.