Prolific mice numbers highlight risk of zoonotic disease

On World Zoonoses Day, Australia’s Chief Veterinary Officer Dr Mark Schipp has highlighted how the risk of zoonoses, diseases which can be transmitted to humans from animals, can be reduced through practising good animal biosecurity and hygiene control procedures.

The bacterial disease leptospirosis is an example of a zoonotic disease of worldwide importance. The disease has been reported in over 150 mammalian species around the world, including wildlife, rodents, cattle, pigs, horses, dogs,  and people.

The Leptospira bacterium that causes leptospirosis is spread through the urine of infected animals. The urine can get into the soil or water and survive there for weeks to months, posing a risk to other animals and people.

“The large number of mice currently affecting areas of eastern Australia is increasing the risk of leptospirosis, especially for people, cattle and dogs,  either through direct contact with rodents, or via contact with stagnant water, such as puddles and ponds which have been contaminated by rodent urine,” Dr Schipp said.

Although leptospirosis is relatively rare in Australia, it is more common in warm and moist regions such as north-eastern New South Wales and Queensland, with the risk increasing in areas affected by flooding.

In affected areas, where there is exposure to infected urine of domestic and wild animals, leptospirosis can be an occupational and recreational hazard to people. 

This includes for those working in the agricultural sector, veterinarians dealing with potentially affected animals, or people swimming or wading in contaminated water.

“Avoiding contact with rodent populations and being aware of the potential disease risks when working or undertaking recreational activities in affected areas is important,” Dr Schipp said.

“Veterinarians play a vital role in the control of leptospirosis by educating farmers and dog owners about the risks to cattle, pet dogs and to themselves.”

Dairy farmers should ensure their herd is vaccinated, provide protective clothing and appropriate barriers in the dairy to protect their staff, and keep staff and visitors to the dairy to only those essential. 

Vaccination of dogs against leptospirosis is an important method of disease control in this species and may reduce the zoonotic risk to humans.

“Diseases like leptospirosis highlight the importance of a One Health approach in recognising the interconnectedness of people, animals and our shared environment, to addressing the complex challenges of preventing zoonotic diseases,” Dr Schipp said.

“On World Zoonoses Day as we reflect on the risk of zoonotic diseases, we can all be part of the efforts to minimise and prevent the risks posed to human and animal health by zoonoses through practicing good hygiene procedures when interacting with animals.

“Being aware of how zoonotic diseases can potentially spread from animals to people can help prevent the spread of zoonotic diseases.”