Veterinary Internal Medicine Nursing

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17 | How to confidently treat and nurse dogs with leptospirosis

Laura Jones

This week, we’re chatting about a disease we’re seeing more and more often in practice and one that has significant risks to both us and our clients: leptospirosis.

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Leptospirosis is an increasingly common, potentially fatal zoonotic disease found throughout the world.

These patients often benefit from advanced treatment and nursing care, especially if they have acute kidney injury as a result of their infection. In today’s episode, we’ll examine leptospirosis, how it affects our patients, and how we can provide the best possible care to them.

What is leptospirosis, and how does infection occur?

Lepto is an emerging zoonotic disease that is being diagnosed more and more in our patients. It affects many organ systems, and the disease varies in severity, from no or very mild clinical signs all the way through to severe acute kidney injury, hepatopathy and vasculitis.

The host (most commonly dogs, but also other mammalian species, including humans) becomes infected with bacteria belonging to the leptospira species.

These are tiny, flexible, filamentous, gram-negative, spiral-shaped bacteria known as spirochetes. They have a flagella that allows them to swim or crawl, making them highly invasive. The bacteria are also protected within an envelope, making them harder to eliminate than non-enveloped bacteria.

Not every species of leptospira bacteria is pathogenic - of the different species, the one we tend to worry about the most is leptospira interrogans.

There are over 250 specific, individual, pathogenic variations (termed ‘serovars’) of L.interrogans, including canicola, grippotyphosa, icterohaemorrhagiae and pomona. We protect against these serovars in current vaccinations.

Which patients are affected?

Dogs become infected with leptospirosis when their mucous membranes or broken skin come into contact with the urine of an infected reservoir host. Infection can also occur from contact with a contaminated substrate, e.g., water or soil contaminated with infected urine.

Any of our canine patients can have leptospirosis—even vaccinated ones—because there is a chance that the patient could become infected with a serovar they are not vaccinated against. 

This means we need to consider leptospirosis as a differential in any dog with consistent clinical signs—even if they’re not considered “high risk” for exposure.

And what are the clinical signs?

The clinical signs and examination findings vary, depending on how severe the illness is at the time of presentation, which serovar the patient has, and the patient’s overall immune status.

Clinical signs are usually acute in onset, occurring within the first week of infection. They vary from mild lethargy and pyrexia, which may be self-limiting, to severe AKI, haemorrhage, vasculitis, and hepatic injury. Other signs seen less commonly include reproductive failure and uveitis.

Signs commonly reported in dogs with leptospirosis include:

  • Lethargy

  • Joint and muscle pain

  • Oliguria or anuria

  • OR polyuria

  • Inappetenace

  • Vomiting

  • Diarrhoea

  • Jaundice

  • Signs of bleeding (melena, petechial haemorrhage, haematochezia, epistaxis)

  • Conjunctivitis

  • Tachypnoea

How do we diagnose leptospirosis in dogs?

Once you suspect leptospirosis, you need to do a few things. Firstly, we need to assess the impact the leptospirosis is having on the patient, such as organ function and haemostasis.

We also need to confirm our diagnosis of leptospirosis through infectious disease testing - and we have a few different options for how we do this.

Let’s start by looking at our routine bloodwork. The most common biochemical changes in dogs with leptospirosis are acute changes to our renal and hepatic parameters. Azotaemia is commonly reported, with 80-90% of dogs demonstrating increased creatinine levels.

30-50% of patients have increased liver enzymes (ALT, AST, ALP) and bilirubin. Other biochemical changes we can see include electrolyte changes, hypoalbuminaemia, and increased creatine kinase.

Haematology may show anaemia, thrombocytopenia, and neutrophilia. And if you’re looking at urine, you’ll typically find glucosuria, proteinuria and a low USG. Be very careful handling urine from these patients since it poses a risk to human health and is a source of leptospirosis transmission.

Speaking of urine, we cannot grow leptospira bacteria with a traditional bacterial culture or view them with routine microscopy. Instead, we need to send that urine for a leptospirosis PCR - where they look for bacterial DNA within the sample. If you’re sending this, ensure your patient hasn’t had any antibiotics beforehand, which can cause false negative results.

So that’s one confirmatory test we can use to diagnose leptospirosis, but what other tests are available? We have a couple more options - the patient-side leptospirosis SNAP/witness test or sending serum away for a microscopic agglutination test (MAT).

So you’ve diagnosed your patient - but how do you treat them?

The good news is that leptospirosis itself is simple to treat—it’s just a case of administering antibiotics, and we tend to use either IV penicillin-based antibiotics (such as amoxiclav) or oral doxycycline. Typically, we start IV amoxiclav first since these patients are often vomiting and anorexic and may not be able to tolerate oral medications. Once these signs improve, they usually move to doxycycline.

It’s not as simple as just administering antibiotics, though - on top of this, these patients often have acute kidney injury, hepatopathy, pulmonary injury, or even bleeding disorders. Each of these has very different requirements for supportive treatment and nursing care.

And how do we nurse these patients in the hospital?

Alongside the specific treatment of the leptospirosis infection itself and associated renal, hepatic, or pulmonary injury, there is a lot to think about when caring for these patients.

They require intensive monitoring, including cardiovascular parameters, renal parameters, PCV and total solids, venous blood gases (or arterial blood gases if your patient has hypoxaemia), and blood smear examinations to check platelet levels. As always, we adjust the frequency of these based on the individual patient’s condition - but general recommendations are to assess renal parameters at least daily (depending on how elevated they are). Because of the frequent sampling, sampling lines are an excellent nursing consideration since we can use these both to collect samples without venepuncture and administer fluids and medications.

They also require careful assessment of fluid balance, matching fluids in and fluids out, and tapering fluid therapy as azotaemia improves and polyuria resolves.

As with any other medical patient, nutrition is a vital nursing consideration for leptospirosis. These patients are often anorexic or hyporexic and have renal and hepatic injury - so get food into them ASAP. Place a feeding tube if needed (we usually place a naso-oesophageal tube), calculate their RER, and formulate a feeding plan depending on the duration of their anorexia.

Infection control is vital alongside nutrition, fluid balance, monitoring, sampling, and IV access. We know leptospirosis is a zoonotic condition, so it poses a risk not just to our patient but to us and their families, too. When nursing a leptospirosis patient:

  • Place a warning sign on their kennel

  • Limit the patient’s movement around the hospital

  • Wear PPE when handling the patient or their environment

  • Walk the patient frequently to minimise their urinating in their kennel

  • Clean the patient’s environment or any areas they have urinated with a disinfectant that inactivates the leptospires

  • Wash and tumble dry bedding normally with hot water and detergent


So that’s an overview of a common cause of AKI in dogs - leptospirosis! These patients present with varying degrees of renal and hepatic injury, and the prognosis is variable. If aggressive medical therapy is administered, including dialysis where indicated, the prognosis is good - with a survival-to-discharge rate of approximately 80%. Patients who have severe azotaemia, oliguria or anuria who do not receive dialysis or patients with pulmonary haemorrhage syndrome have a poorer prognosis and survival rates of 40-50%.

These patients benefit from intensive nursing care and monitoring, and we can perform plenty of skills with them —from urinary catheter placement, feeding tube placement, sampling line placement, and nutritional and fluid balance monitoring to caring for patients on mechanical ventilation.

Did you enjoy this episode? If so, I’d love to hear what you thought - screenshot it and tag me on Instagram (@vetinternalmedicinenursing) so I can give you a shout-out and share it with a colleague who’d find it helpful!

Thanks for learning with me this week, and I’ll see you next time!

References and Further Reading