Dog - Leptospirosis

What is leptospirosis?

Leptospirosis is a bacterial disease of dogs that affects blood, liver, or kidneys. There are several types of leptospira (spiral shaped bacteria) that can be responsible for the disease. It can affect dogs and also humans. Rats and other rodents carry the disease but recovered dogs can also act as carriers. Infected urine is the usual source of infection.

How common is leptospirosis

The disease does occur in the UK, affecting in particular stray or unvaccinated dogs. In urban areas it is mainly spread by the urine of infected dogs whereas in rural areas another type of leptospira bacteria is more common and is spread by the urine of infected rats. Due to routine vaccination the disease in Britain is now less than it was but it still occurs and it should be remembered it is zoonotic, i.e. can cause so-called Weil’s (pronounced 'Viles' ) disease in man.

How is it transmitted?

Ingestion of the causal organism from infected urine is the most important means of transmission in the dog but some forms of the bacteria can penetrate damaged or very thin skin. The incubation period (from infection to onset of clinical signs) is usually 4-12 days.

What are the signs of leptospirosis?

Some infections are undetected (asymptomatic) but the dog can still act as a carrier. Acute cases can be life-threatening. There are three main forms of the disease: haemorrhagic (bleeding), icteric or jaundiced form (involving the liver), and also the renal (kidney) type. In the acute disease there is high fever with lethargy and loss of appetite. Bleeding can occur in the mouth, the bowel and on the whites of the eyes. Bloody diarrhoea and vomiting are common. This form can be rapidly fatal. If the liver is mainly affected, although the early signs are similar to the haemorrhagic form, jaundice (icterus) a yellow colour can occur affecting the mouth or the whites of the eyes. Sometimes even the skin is yellow. In the renal form kidney failure can occur. The dog is very lethargic, off food and vomits. Often the breath is offensive (uraemic) and there are ulcers on the tongue and inside the lips. If the dog recovers, chronic kidney disease often follows.

Is leptospirosis common?

This disease is not common in Britain because of widespread use of vaccines to prevent it in dogs and prevent its spread to man. However, stray, unvaccinated dogs can be infected and may be carriers.

What is the treatment?

Since leptospirosis is caused by bacteria, appropriate antibiotic treatment is effective if the condition is diagnosed early enough. Dogs are often so ill when presented that hospitalisation and intensive nursing care, including intravenous fluids (drip), are usually necessary.

How is it prevented?

Leptospirosis vaccination is today generally part of the routine vaccination programme. The vaccines used are killed vaccines (inactivated) and therefore cannot be responsible for spread of the disease although very occasionally they can cause a mild reaction themselves.