Rats blamed for spread of Leptospirosis in Sydney dogs

by Reinisch S Veterinary writer
26 Sep 2019

Leptospirosis is a bacterial disease that can infect a wide variety of animals including humans. The bacteria is most commonly spread through contact with soil, water or vegetation that has been contaminated with urine from infected animals.

It is mostly found in warmer climates and therefore more common in north-eastern NSW and Queensland. However, in recent months there have been a number of confirmed cases in dogs in Sydney, which is an area where the disease was considered rare and routine vaccination against canine leptospirosis was not required.

Since this cluster of cases, the disease has resulted in the death of at least seven dogs, whereas prior to this NSW had never reported a canine death from the disease.

The exact cause of this cluster of disease is unknown but the city's rat population is a suspected culprit.

A recent boom in major construction and infrastructure projects around the city has resulted in the disruption of local rat populations with many rats seen on the move around the city. As a result, the City of Sydney doubled their rat baiting efforts in August to reduce rat populations, with 860 rat bait stations placed in public areas around the city.

They have also called on local businesses and residents to do the same and ensure that all food scraps and waste is disposed of correctly to prevent attracting more rats to the area.

To reduce the risk of infection in dogs and subsequent spread to owners, it has been advised that dogs in the area should be vaccinated against leptospirosis and also be prevented from swimming in any lakes or ponds as they could be a contaminated source of the disease.

Thankfully during this initial cluster of disease, no dog-to-human spread has been reported. In humans, the disease will often present with flu-like symptoms, but in rare cases can lead to severe symptoms which require hospitalisation and can even result in death.


  1. https://www.theguardian.com/australia-news/2019/jul/10/rare-disease-spread-via≠rat-urine-kills-seven-dogs-and-leaves-dozens-of-australians-ill 
  2. https://news.cityofsydney.nsw.gov.au/media-releases/city-of-sydney-to-double-rat-baits

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