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The contagious disease known as canine leptospirosis, caused by a bacterium known as leptospira, leads to bacterial infection in dogs. Other animals, as opposed to just dogs, can be infected including other mammals, birds, reptiles and amphibians. In the most severe examples of animals contracting leptospirosis death can be a result and can occur within a just a few hours. Some animals may act as carriers without showing any clinical signs and so further transmission may result. The bacteria initially enter, via contact with urine, into the blood stream and travel to the animalís organs such as the liver, kidneys, nervous system, eyes, and reproductive organs. Puppies have the most risk concerning this disease as their immune systems have not yet matured to be strong enough to fight it off. Canine leptospirosis is treatable though a preventative measure such as vaccination is highly favourable. It must be noted that this is a zoonotic disease although the incidence of this is very low.


Infected animals pass on the leptospira bacteria as they urinate. Via contact with infected urine or contaminated water the bacteria can enter other animals through the mouth, eyes, open wounds, and skin abrasions. Transmission can also be the result of an animal feeding on an infected organism or if the bedding is contaminated. The bacteria thrive in humid and wet environments and so animals that enter the water frequently are more prone to infection. Warm, stagnant and slow moving water is an ideal breeding area for the leptospira bacteria.

Kennels pose a large risk to dogs and so kennel owners should take special care to disinfect all areas since this is a very contagious disease. It is normal behaviour for dogs to lick and smell urine and so within households where a dog has been infected strong disinfectants should be applied to areas where the dog has urinated. Dogs can take up to a few weeks before presenting any signs or symptoms but as soon as any are spotted it is very important to contact a veterinarian.


It may take a couple of weeks before any symptoms can be observed after coming into contact with the bacteria. The initial signs are a high temperature, vomiting, lethargy, and depression. Appetite may be lost, there can be diarrhoea and the kidneys may be sore. Due to the diarrhoea and vomiting, the dog can experience dehydration. If the liver is attacked then jaundice will be observed, usually around the gums. In the most severe cases fatalities occur, generally due to liver or kidney failure.

Treatment and Prevention

The treatment for leptospirosis includes using antibiotics such as penicillin and tetracycline which are commonly administered to destroy the bacteria. If the dog is dehydrated then IV fluids are given to replace the lost water. If there is any liver or kidney failure then these will be treated accordingly.

Prevention is better than cure. Vaccines are widely available for the variable strains of the leptospirosis bacteria and owners should consult their veterinarians for advice. Boosters should be given twice annually in areas where there is considered a greater risk as the vaccine only provides protection for around six to eight months. Some dogs are allergic to the vaccine and so if symptoms such as hives or redness are observed then the veterinary practice should be contacted immediately.

Diagnosis and Prognosis

Blood tests and urine test can be used to give a positive diagnosis for leptospirosis. These will also show whether there is any liver or kidney damage and so help the veterinarians acknowledge which treatment plans to follow. The prognosis for mild cases is good although as the disease develops it can become fatal.  


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