85 | Tick-borne disease in dogs: what do vet nurses NEED to know?

PodcastInfectious diseaseCanine medicineHaematologyImmune-mediated Disease
Written By Laura Jones

Tick-borne disease is on the rise, and there’s a good chance you’ll see it if you haven’t already.

 

This is particularly true if you work in first opinion practice, internal medicine, emergency and critical care, or rescue and rehoming settings.

The four main tick-borne diseases veterinary nurses see in dogs:

  • Borrelia burgdorferi, which causes Lyme disease

  • Anaplasma phagocytophilum

  • Ehrlichia canis

  • And Babesia species, most commonly Babesia canis

In the episode, we’ll look at what each of these diseases causes, how they present, how we test for and treat them, and - most importantly for us - what we can do as nurses and technicians to care for these patients.

What are tick-borne diseases, and why are we seeing more of them?

Ticks are becoming more common across the UK, with expanding habitats and a longer active season due to climate change, longer vegetation seasons, and higher populations of deer.

Ixodes ticks are prevalent and are now found not just in moorlands and forests, but also in urban green spaces, such as parks and gardens. This means our dogs are more likely than ever to be exposed, especially if they walk in long grass, rural areas, or wooded environments.

Alongside this, there’s been a sharp increase in international dog travel and rescue over the past few years, particularly from countries in Eastern and Southern Europe where diseases like Ehrlichia and Babesia are endemic. Many of these infections come with prolonged incubation or subclinical periods, meaning dogs can arrive in the UK appearing healthy, only to develop signs weeks or months later, or to transmit disease unknowingly to other dogs or local ticks.

Let’s look at our first disease: Borreliosis, aka Lyme Disease.

Borrelia burgdorferi is the bacterium responsible for Lyme disease. It’s transmitted by Ixodes ticks, which are present in the UK. While we see far fewer cases in dogs than in humans, veterinary cases are increasing, particularly in areas of Scotland, Wales, and Southwest England.

Once transmitted, Borrelia can cause a range of clinical signs.

These include vague and non-specific signs such as pyrexia, lethargy and inappetence - and some more specific signs, too.

The most classic clinical sign associated with Lyme disease is polyarthritis, or shifting limb lameness. Here, dogs will have intermittent stiffness and lameness accompanied by joint pain and effusion. The immune system can also cause polyarthritis, but ruling out Borrelia is essential in any patient with these signs.

Borrelia can cause severe complications that can include:

  • Glomerulonephritis: Inflammation in the glomeruli within the kidneys, causing protein-losing nephropathy (which we discussed back in episode number 15) and progressive renal disease

  • Neurological signs, including facial nerve paralysis or behavioural changes

We typically suspect Lyme disease in patients with a history of tick exposure, especially those with waxing and waning lameness, those vague, non-specific signs we mentioned, or joint pain. 

So that’s what Lyme disease is - but how do we diagnose, treat and care for patients with it?

Diagnosis is made on bloodwork - usually via an in-house 4Dx test, or external antibody testing.

The SNAP test uses ELISA (enzyme-linked immunosorbent assay) technology to detect C6-antibodies specific to Borrelia burgdorferi, rather than other Borrelia species, confirming previous exposure. Bear in mind, though, that antibody production can take several weeks, so false negatives can occur if we test an infected patient too early.

Other tests performed in these patients include general biochemistry and haematology, urine analysis, C-reactive protein testing (a marker of inflammation increased in patients with polyarthritis), diagnostic imaging, and potentially limb x-rays and joint sampling, if indicated based on the individual patient.

Treatment is straightforward, and most patients respond well to a prolonged course of doxycycline. Alongside this, we’ll provide supportive treatment, including analgesia for patients with joint pain, fluid therapy and antiemetics as needed to patients with renal involvement, and medications to treat proteinuria where required.

As nurses, we can support these patients by managing pain, encouraging gentle activity to maintain joint mobility, and monitoring urine output and renal function if indicated.

Next up, we’ve got Anaplasma.

Anaplasma is another tick-borne bacterial disease, also transmitted by Ixodes ticks, and it’s present in UK tick populations. There are two types: Anaplasma phagocytophilium and Anaplasma platys. 

Anaplasma phagocytophilium infects neutrophils and causes inflammation and immune dysregulation. It can also trigger or contribute to immune-mediated diseases like immune-mediated thrombocytopenia and haemolytic anaemia.

Anaplasma platys infects platelets, causing an infectious cyclic thrombocytopenia.

Dogs with anaplasmosis often present with pyrexia, lethargy, and muscle or joint pain.

If your patient has significant thrombocytopenia, you’ll see associated clinical signs, including:

  • Petechiation

  • Ecchymoses

  • Epistaxis

  • Gingival haemorrhage

  • Scleral haemorrhage

  • Haematuria

  • Melena

Immune-mediated anaemia is also possible, though less common. That being said, if you have a thrombocytopenic patient with significant haemorrhage, you’ll see signs of transfusion dependence, such as pallor, tachycardia and bounding pulses, tachypnoea, or bradycardia with weak pulses.

Like Borrelia, Anaplasma can be detected using a SNAP 4Dx test.

This identifies circulating antibodies against both species of Anaplasma. PCR testing is also commonly performed and can be used to confirm an active infection.

Very occasionally, you can see bacterial inclusions - known as morulae - on a blood smear in an infected patient. These morulae are clusters of bacteria inside the patient’s neutrophils. So if you come across one of these patients, definitely take a look at a smear and see if you can spot any! 

And treatment is very similar to Borrelia, too.

These patients usually receive a 2-4 week course of doxycycline, depending on the severity of their signs, alongside supportive treatment.

As nurses, our priority when caring for these patients is monitoring for and preventing haemorrhage. Keep a close eye on venepuncture sites, keep the patient calm and rested, monitor for bruising or petechiation, and handle the patient carefully.

In severe cases, depending on the extent of our patient’s anaemia, we may also assist with blood typing, blood donation, transfusion preparation, and monitoring.

Our third disease is Ehrlichia canis.

Ehrlichiosis is most commonly caused by Ehrlichia canis, a bacterium transmitted by Rhipicephalus sanguineus, the brown dog tick. This tick is not native to the UK, but is found in other locations worldwide and can survive indoors, making transmission possible via imported or travelling dogs.

Ehrlichiosis infects white blood cells and has three clinical phases: acute, subclinical, and chronic.

In the acute phase of disease, patients usually present with anorexia, weakness, pyrexia, lethargy, and mild bleeding tendencies such as epistaxis or petechiae. Lymphadenopathy and weight loss are also common.

If missed at this stage and left untreated, the infection may progress to the subclinical phase, where no outward signs are visible. This phase can last for months or even years, during which the dog remains infected but appears healthy.

Some dogs will then progress to the chronic phase of disease. Here we see more severe signs, including pancytopenia - decreases in red and white blood cell counts and thrombocytopenia - alongside immunosuppression, ocular changes, severe weight loss and cachexia. These patients present with signs of bleeding and anaemia, alongside uveitis, retinal detachment, and blindness. Renal failure, pneumonitis and respiratory signs can also be seen. Rarely, patients present with neurological signs secondary to meningitis.

Diagnosis is made via antibody testing, with a PCR for confirmation. 

Blood smears may show Ehrlichia morulae, but this is rare. Biochemistry may reveal hyperglobulinaemia or mild changes to our patient’s liver enzymes, and haematology often shows lymphocytosis, thrombocytopenia or pancytopenia in chronic disease.

In patients with chronic disease and pancytopenia, we’ll likely perform a bone marrow biopsy, which can reveal Ehrlichia within bone marrow cells.

Treatment again involves long courses of doxycycline - but that’s not all. 

In chronic cases, antibiotics alone may not be enough to reverse bone marrow damage, and so supportive care is vital. As nurses, we play a huge role in these cases - we’ll be administering blood products, supporting renal function, supporting nutrition in patients with severe weight loss, and much more.

And lastly, we’ve got Babesiosis. 

Babesiosis is caused by protozoan parasites that infect red blood cells, most commonly Babesia canis (aka ‘large Babesia’) in Europe, and less commonly Babesia gibsoni (aka ‘small Babesia’). Transmission is via tick bites, usually from Dermacentor or Rhipicephalus species. 

Babesiosis causes varying degrees of illness and can be fatal in severe cases. We usually see it in dogs, but it can affect other species, including humans - though as it’s spread through vectors, it’s not a disease you’ll catch from a patient directly.

What does Babesia do, and what signs do we see in infected patients?

Babesia species infect the patient’s red blood cells, causing intravascular haemolysis and anaemia - essentially, a form of IMHA that is not immune system-mediated.

Patients present with non-specific signs initially, including lethargy, weakness, depression and pyrexia.

These often progress to pale mucous membranes, signs of transfusion-dependence, jaundice and weight loss. Haemoglobinaemia and haemoglobinuria can also be seen in the later stages of the disease.

Unlike our other diseases, we can’t use a 4Dx to diagnose Babesia.

Instead, we’ll perform IFAT (immunofluorescence assay testing) followed by a PCR to confirm infection. The PCR also allows us to identify the specific Babesia species involved; this is essential, since small and large babesia require different treatments.

In some cases, we can see inclusions within red blood cells on the smear of an infected patient, though these are hard to spot, so they shouldn’t be relied upon alone for diagnosis.

And talking of treatment…

Imidocarb, an antiprotozoal drug, is used to treat Babesia canis infection, while atovaquone is used to treat Babesia gibsoni, alongside the antibiotic azithromycin. Patients also need aggressive supportive care, including blood transfusions, IV fluids, oxygen therapy, and careful monitoring for shock.

As nurses, we’ll be managing these patients like our IMHA cases - monitoring them carefully, looking out for subtle signs of deterioration or transfusion reactions, and providing intensive supportive care.

So now we know what these diseases are and the problems they cause, what can we do as nurses and technicians?

Firstly, recognise the risk factors. If a patient is an imported dog, has recently travelled, or spends time in tick-heavy areas, you should have a higher index of suspicion for tick-borne disease. 

And while it’ll be the vets diagnosing the patient, we’re often involved in collecting histories and discussing with clients, so ask about travel history wherever you’re doing this.

Secondly, support the patient during diagnosis. This means knowing what tests we’re using, understanding what the results mean, collecting samples under the vet’s direction, and even things like looking for inclusions on the blood smears of infected patients.

Veterinary nurses should provide specialized and detailed nursing care that includes:

  • Monitoring and supporting patients with anaemia, thrombocytopenia, or immunosuppression

  • Minimising bleeding risk in thrombocytopenic patients

  • Barrier nursing for infectious or immunocompromised patients

  • Preparing, administering and managing transfusions

  • Educating clients about tick prevention and travel


That’s it for this week’s episode and our infectious disease series! I hope you now feel more confident in recognising and caring for dogs with tick-borne disease. While these infections aren’t always common, they’re becoming more frequent - and many of them need intensive nursing care, with lots of skills we can use in the process.

Did you enjoy this episode? If so, I’d love to hear what you think. Take a screenshot 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

Laura Jones
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