Recent publicity about dogs in the Sydney region dying from leptospirosis has shone a spotlight on a disease that most dog owners have not heard of before.
Leptospirosis is caused by Leptospira bacteria, of which there are hundreds of types, some of which can cause disease in humans and animals.
The disease is relatively rare in Australia, though more common in warmer, more humid environments such as Queensland, the Northern Territory and north east New South Wales.
Vaccination is recommended in areas where the disease is known to occur.
Leptospirosis can cause acute kidney failure and liver disease in dogs, which can be fatal.
During the past 18 months, 11 dogs in Inner Sydney are known to have been infected, with 10 of those dogs dying.
Affected dogs may be very lethargic or seemingly depressed.
They may experience abdominal pain, vomiting, diarrhoea, changed frequency and volume of urination, increased thirst and blood in their urine.
They may also develop jaundice, a yellow discolouration of the skin and mucus membranes, most evident on the gums or the whites of the eyes.
Dogs become infected with leptospirosis through contact with urine from rats, or indirectly through ingestion of contaminated water or soil.
Dogs can also become infected by hunting and catching rats.
Some dogs, particularly terriers, are known "ratters", but dogs have contact with rats more often than owners may suspect.
Rats tend to keep well out of sight when humans are around, but emerge from their nests during quiet periods, usually at night.
I recently stayed with a friend who swore that her mostly-indoor dwelling Australian shepherd dog had no contact with rats.
We decided to test this assumption, placing a motion-activated camera in her garden.
The camera not only caught rats emerging after dark, but the dog was caught on camera minutes later sniffing the scene.
Prevention is based on limiting contact with sources of infection, and vaccinating dogs.
It is important to keep dogs away from stagnant water like ponds or puddles, as well as mud.
Typically, the leptospirosis vaccine is not considered a "core" vaccine and thus is not covered by the standard C5 vaccine.
However, there are vaccines available in Australia.
In Sydney, leptospirosis in dogs has been associated with the type Copenhageni, for which an effective vaccine is available.
There are other vaccines available for strains that are prevalent in other regions.
It is important to ask your vet which vaccine is most appropriate for your dog.
In relation to the recent spike in cases in the Sydney region, the good news is that there have been no cases in vaccinated dogs.
Dr Christine Griebsch, Senior Lecturer in Small Animal Medicine from the Sydney School of Veterinary Science, recommends that owners of dogs living within a five-kilometre radius of suburbs where cases have been reported talk to their veterinarian about vaccination.
The vaccine is given twice, two to four weeks apart initially, and annually thereafter.
It is important to note that leptospirosis is a zoonotic disease, which means that humans can become infected via exposure to the urine of rats or infected dogs through skin wounds or through mucous membranes.
As always, hand hygiene is very important in preventing the spread of this disease.
If your dog is unwell and you suspect they have been exposed to rats, it is important to let your veterinary team know so that they can take suitable precautions.
Dr Griebsch is undertaking research on canine leptospirosis in the Sydney region to try to understand how common the condition is and likely sources of infection.
Dr Fawcett, BVSc(Hons), MANZCVS (Animal Welfare), Dip ECAWBM (AWSEL),is a lecturer at the Sydney School of Veterinary Science and a practising veterinarian.