Zoonoses and zoonotic diseases


If you work with animals you may have heard the term ‘zoonosis’. This article aims to explain what this word means and what some common zoonoses are.

What is a Zoonosi?

A zoonosis (plural zoonoses or zoonotic disease) is a disease caused by an infectious agent such as a bacterium, virus, fungi or parasite that can be transmitted from animals to humans.  

Why do Zoonotic diseases matter?

Zoonses account for 60% of existing human infectious disease and at least 75% of emerging infectious diseases of humans (OIE statistics).

Infected animals may not show the severity of illness as infected humans do but disease in food producing animals can cause major losses in production. Zoonotic disease can have serious long term health complications in humans so it is important to take precautions to minimise the risk of contracting one of these diseases. People that live and work around livestock and wildlife are at greater risk of contracting a zoonotic disease.

What are some common Zoonoses and who gets them?

One of the most well-known zoonotic diseases in the world is Rabies. The Rabies virus is often spread to humans from the bite of an infected animal, where infected saliva comes in contact with broken skin. Luckily, Australia does not have Rabies.

There are numerous zoonoses in the world, but the best way to work out which ones are most relevant to your area is to visit your state or territory agricultural or government health website or contact your general practitioner or veterinarian.

Some of the common zoonotic diseases in Australia include:

Q Fever - This disease is caused by the bacteria Coxiella Burnetii. Cows. Sheep and goats are common transmitters to humans, where it can be found in high levels in infected animals’ urine, faeces, placentas and other birthing fluids. It most commonly affects abattoir workers, veterinarians, veterinary nurses and livestock workers who may be exposed to these infected tissues.

Less commonly dogs and cats and wildlife may be sources of Coxiella Burnetii. It is recommended that abattoir workers, veterunarians, veterinary nurses, livestock workers, dog and cat breeders and wildlife carers be vaccinated against Q Fever.

Leptospirosis - In Australia, Leptospirosis is caused by the bacteria Leptospira. Although it can infect many domestic and wild animal species, Leptospira is most commonly transmitted to people through the infected urine of cows, sheep and goats. Infected urine can in turn contaminate soil and water sources.

Not only can this be a hazard for farmers and abattoir workers, but the disease can also be transmitted to people swimming, camping or in close contact with contaminated water sources.

Ringworm - Despite its name Ringworm is not actually a worm at all. It is a fungal skin infection also known as dermatophytosis and is transmitted through direct contact with an infected animal.

Cats, dogs, rabbits, cows, sheep and many more domestic and wild animals may be affected. It more commonly affects young people and animals or those with a compromised immune system. 

Other zoonotic diseases include:

  • Hendra virus
  • Psittacosis
  • Salmonella
  • Australian Bat Lyssavirus
  • Brucellosis
  • Avian Influenza
  • Anthrax
  • Emerging coronaviruses e.g. SARS, MERS, COVID-19

Most zoonoses come from livestock including pigs, chickens, cattle, goats, sheep and camels.

Veterinarians play an important role in helping to prevent zoonotic diseases by keeping animals healthy and vaccinating them for hendra, brucellosis, avian influenza, anthrax and leptospirosis.