Leptospirosis

Leptospirosis is a bacterial disease of dogs that can affect the blood, liver, or kidneys. It is caused by bacteria that are spiral shaped.

How do dogs acquire the infection?

The bacteria are carried mainly by rats and other rodents, but infected dogs can also act as a source of the infection. Ingestion of infected urine is the most important means of transmission, 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?

Many infections go undetected, but many other cases can be life-threatening. There are three main forms of the disease: haemorrhagic (bleeding), icteric or jaundiced form (liver), and renal (kidney). In the haemorrhagic disease there is early high fever with lethargy and loss of appetite. Multiple small haemorrhages occur in the mouth and on the whites of the eyes. Bloody diarrhoea and vomiting may occur. This form is often fatal. The jaundice form begins much like the haemorrhagic form, and many of the signs are the same. It differs in the presence of a yellow colour (jaundice or icterus) in the mucous membranes of the mouth. The whites of the eyes are also a good place to look for the yellow colour. In severe cases in dogs with white hair, the skin will turn yellow. The renal form causes kidney failure. These dogs are very lethargic, anorectic, and experience vomiting. There may be a characteristic offensive odour from the mouth and ulcers often develop on the tongue and inside the lips. This form may be fatal, but recovered dogs often have chronic kidney disease.

How common is leptospirosis?

This disease is not common in Australia. When seen, it is more common in warm, wet climates or seasons. Sporadic cases occur in dogs (including serovars copenhageni and australis). The incidence of leptospirosis in dogs varies from state to state with the incidence in Queensland being highest whilst incidence in NSW is low and in the ACT very low. Most human infections are associated with rat urine, for example in cane fields in northern NSW and Queensland.

What is the treatment?

Antibiotics are reasonably effective if they are begun early enough in the course of the disease. However, often dogs are so ill when presented that hospitalisation and intensive nursing care, including intravenous fluids, are usually necessary.

"Antibiotics are reasonably effective if they are begun early enough in the course of the disease."

How can leptospirosis be prevented?

The vaccine for leptospirosis may be part of the routine vaccination program if regional prevalence is high. Annual boosters may be needed to maintain proper immunity.

Can the vaccine cause reactions?

The vaccine used is a killed vaccine and although, as with any vaccine, individual reactions can occur, vaccination even of young puppies is unlikely to result in any reaction to cause concern.