Canine leptospirosis: disease review | Vets & Clinics

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Canine leptospirosis: disease review

Canine leptospirosis is transmitted through the urine, but it can also cross the placenta, be spread by bites, contact with rats or by eating contaminated meat. The microorganism initially infects the mucous membranes or skin wounds and then passes into the bloodstream (leptospiraemia, after 4–12 days). Then it invades the renal epithelium and hepatic parenchyma. It may also damage the central nervous system, placenta and uvula.

Veterinary medicine and care

Canine leptospirosis is caused by the serotypes Leptospira icterohaemorrhagiae and canicola. It occurs more commonly in spring and autumn due to moderate temperatures and low humidity.

What does canine leptospirosis entail?

Canine leptospirosis can cause acute or chronic clinical signs. In acute cases, widespread leptospiraemia results in vasculitis and even DIC. Acute kidney failure and hepatic necrosis with cholestasis also occur.

On the other hand, chronic cases can course with fever, uveitis, chronic interstitial nephritis and hepatitis. Patients manifest anorexia, depression, fever, vomiting, paresis of the hindlimbs and even dyspnoea.

A very notable sign is dark urine with haemoglobin, proteinuria and glycosuria, while granular cylinders, erythrocytes and leukocytes can be seen under an optical microscope. Laboratory tests reveal lymphopaenia with leukocytosis, thrombocytopaenia, azotaemia, increase in necrotic enzymes, hepatic cholestasis, hyponatraemia and even DIC.

Treatment of canine leptospirosis

An aggressive treatment is required if there is acute kidney failure. Fluid replacement therapy and furosemide-forced diuresis must be introduced to maintain a urinary output of 2–5 ml/kg/h. If furosemide is not sufficient, treatment with mannitol or dopamine will have to be introduced and peritoneal dialysis may even be required.

Blood transfusions are required if there is marked coagulopathy or DIC.

Broad-spectrum antibiotic therapy (benzathine penicillin g) must be started as soon as possible. Doxycycline is recommended for about 2 weeks after finishing the course of penicillin, to try to eliminate Leptospira from the kidneys.

Prophylaxis

The sick animal must not come into contact with other animals as the infection is mainly transmitted through urine. Veterinary professionals and owners must also take precautions.

Vaccines against L. canicola and icterohaemorrhagiae serotypes protect against the acute presentations of the disease, but not against chronic carrier states. Once the infection has been resolved, annual vaccination is required because there is no cross-protective immunity between the different serotypes.

Prognosis

If the animal is treated in time, the clinical picture can be completely resolved.

Canine leptospirosis in Europe

Changes in canine leptospirosis are taking place across Europe. In addition to the usual serotypes (icterohaemorrhagiae and canicola), new ones are emerging such as bratislava and grippotyphosa.

This is leading virologists to reassess the composition of the vaccines distributed in Europe. There is still a possibility that new serotypes such as pomona must be incorporated in the near future.

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