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The symptoms in the dog vary from very mild or non-existent to a rapidly progressing fatal disease. The ‘classic’ form is described below, but cases may be less severe and/or slower to develop.

Leptospirosis exhibits a wide range of symptoms and may resemble other infectious diseases. However, progression is usually much more rapid than is normal for distemper and canine infectious hepatitis, for example.

Signs include:

  • High fever (which can then drop afterwards)

  • Gastroenteritis with vomiting and diarrhoea which may include blood

  • Jaundice (orange-yellow discolouration) which is typical of leptospirosis. This is due to liver impairment

  • Dark urine

  • Marked dehydration

  • Congestion of the mucous membranes

  • Lethargy

  • Acute renal failure

  • And potentially death of the animal

Some dogs will slowly recover, but initially may be prone to minor recurrent attacks. If dogs do recover, they will eventually return to normal, although some degree of permanent kidney damage is likely. They may also shed the bacteria in their urine for months.


This disease is caused by a type of bacteria called Leptospira, which is found throughout the world. Leptospires can be transmitted directly from an individual’s urine or indirectly via contaminated water. The bacteria can penetrate damaged skin or intact mucosa (e.g. lining of the mouth)

Dogs can spread Leptospira to both humans and other dogs via their urine. Following infection, some dogs become long-term carriers whilst appearing healthy. This may put families and their dogs at risk of serious disease if strict hygiene is not observed. The disease is occasionally fatal to both dogs and humans.


Diagnosis on clinical signs alone can be a challenge as they can be both variable and non-specific. Because of the potential to infect humans, and the need to select appropriate treatment, diagnostic tests may be performed by your veterinary surgeon.


Leptospirosis is a bacterial disease so it can be treated by a number of antibiotics. Supportive therapy for the damaged organs is also essential.

Treatment can also involve:

  • Antibiotic treatment

  • Rehydration - Often a priority, with attention paid to correct salt (electrolyte) levels

  • Medication to control symptoms, such as diarrhoea, vomiting, and pain

  • Nursing care to keep the dog clean and comfortable

  • Certain important hygiene precautions should be taken when handling infected dogs and you should take advice from your veterinary surgeon

Infected and in-contact dogs MUST be isolated from other susceptible dogs and strict hygiene precautions are needed to prevent spread (change of clothing/disinfectants). Unfortunately treatment is not always successful, and the prognosis is especially poor for dogs that show neurological signs.


Leptospirosis can be prevented by vaccination. The leptospirosis component is usually included in the primary vaccination course. The immunity resulting from vaccination is not long lived so annual boosters for Leptospirosis are necessary.

Based on your pet’s specific situation, your veterinary surgeon will select a vaccination protocol to best meet your pet’s needs. Up-to-date vaccination is usually obligatory before going to dog shows and many kennels.

The organism, normally found in water, is rapidly destroyed by light and temperatures above 20ºC, so does not survive long in bright sunlight. It is advisable to keep your dog away from stagnant water in shady areas




Find out more here...

Why it's important to keep on top of your dog's vaccinations