What kind of disease is leptospirosis?

Leptospirosis is a potentially life-threatening zoonotic disease (i.e. a disease that can be transmitted from animals to humans) caused by spirochaetes belonging to Leptospira genus. Spirochaetes are bacteria with both gram-positive and gram-negative characteristics. Leptospira genus comprises 20 different species and over 250 serovars. Leptospirosis is common all over the world.

How do dogs become infected with leptospirosis?

Leptospirosis mainly spreads with the urine of infected rodents. The animals become infected through either direct or indirect contact with the urine of the infected animal or contaminated surface.  Leptospirosis can be found in stagnant waters, mud puddles, or areas densely inhabited by small rodents (mice, rats). Thus, cases of leptospirosis emerge in Estonian climate all the year round, but are more frequent in summer and autumn.

Dogs of all ages may contract the disease. However, working and hunting dogs, as well as those who move a lot in nature (walks in the woods and fields) belong to the risk group. Additionally, dogs who swim in water bodies and drink water from lakes or rivers are exposed to increased risk of contracting the disease.

What are the main symptoms of the disease?

Leptospirosis is a multi-systemic disease mainly affecting kidneys and liver, but able to damage lungs, spleen, eyes, genitals, and nervous system.

Clinical symptoms of leptospirosis are not specific and are mainly related to kidney and/ or liver damage:

• Loss of appetite
• Lethargy
• Vomiting
• Diarrhoea
• Fever or hypothermia (decreased body temperature)
• Abdominal pain
• Jaundice
• Soreness/ Tenderness of joints, lack of desire to move
• Weight loss

In some case, certain lung damage induced symptoms may emerge, e.g. changes in the breathing/ respiration pattern (excessively fast respiration/ breathing, respiratory failure). The animal may suffer from conjunctivitis or uveitis.

How is leptospirosis diagnosed?

Leptospirosis is diagnosed based on the clinical history, clinical symptoms and laboratory findings. Blood sample haematology and biochemistry as well as urinalysis are conducted.  Diagnostic imaging is performed to exclude other diseases with similar clinical symptoms. This is mainly done using x-ray examination/ radiology or ultrasonography.

Express leptospirosis tests are usually performed on all cases when the disease is suspected. Leptospirosis express test determines the presence of the disease antibodies in the blood. The express test may be both false positive or false negative, therefore, it is recommended to send the blood sample to the laboratory for final diagnosis.

How is leptospirosis treated?

Dogs with leptospirosis symptoms usually have to be hospitalized. The treatment includes antibacterial and supporting fluid therapies, administration of gastroprotectants and analgesics. The treatment plan often involves the use of two different antibiotics, as one type of those decelerates the spread of leptospira but does not kill the bacteria, whereas the other destroys the bacteria but does not limit its spread. Therefore, it is essential to use the combination of two antibiotics for successful treatment. When the animal’s overall condition improves and stabilizes, the patient is discharged and the treatment has to be continued at home.

Prognosis

The prognosis for the dogs infected with leptospirosis depends on the severity of the disease. If no serious kidney or liver damage is caused, and the treatment is initiated in time, the prognosis for full recovery is relatively good. In more severe cases, when serious kidney and/ or liver damage is caused, the prognosis may be cautious. In very severe cases (especially if the disease has spread to the lungs), the animals may die. After the end of treatment, it is necessary to repeat blood haematological analysis to evaluate kidney and liver functionality.

Vaccination?

It is possible to vaccinate dogs against the most common leptospirosis causative pathogens. It is necessary to vaccinate the animal every year. Unfortunately, currently available vaccines do not protect dogs against all leptospirosis causative pathogens. Nevertheless, we recommend to vaccinate dogs to develop immunity against the most common serovars.

Leptospirosis in cats

Cats can also contract leptospirosis and disseminate the pathogens via urine, however, they rarely suffer from any clinical symptoms of the infection.