Lyme disease in dogs and cats

Lyme disease is a chronic, debilitating disease that can infect dogs, cats and humans. It’s caused by a spirochete called Borrelia burgdorferi and is spread by ticks, primarily the sheep tick, Ixodes ricinus. Animals become infected following a bite from an infected nymph or adult.

Posted: 29 May 2019

Lyme disease in dogs and cats


At this time of year, ticks can become a real problem for pet owners. Both dogs and cats are frequently bitten, with serious health complications if the tick is carrying disease.

7 signs of Lyme disease

  1. Lameness – this may be seen as limping, which can be either continuous or intermittent. The lameness may also change from one leg to another from one day to another and is sometimes referred to as wandering or migrating arthritis. The painful arthritic joint may be hot and swollen, and episodes of lameness may last several days.
  2. Stiffness – with the lameness comes a stiff stilted appearance. The animal may appear to have a sore neck or back.
  3. Arthritis – the joints develop a non-erosive inflammatory arthropathy.
  4. Lymphadenopathy – in many cases, the animal will develop inflammation and swelling of the lymph nodes, which may be felt under the jaw, in front of the front legs or behind the knee.
  5. High temperature – Lyme’s disease patients usually have a fever.
  6. Bull’s eye lesion – look for a circular mark on the skin resembling the bulls eye of a dartboard. The centre will be red and inflammed. In many cases though you may never see the original lesion as the hair or skin colour will hide it.
  7. Kidney disease - some animals may develop kidney problems associated with a progressive renal failure (immune-mediated glomerulonephritis). The risk of developing Lyme disease associated renal disease appears to be higher in Labrador and Golden Retrievers, as well as Bernese Mountain Dogs. They may develop an increased thirst and weight loss.


In most cases, a diagnosis can be made based on the evidence of a tick bite, plus the clinical signs of shifting lameness, pyrexia and lymphadenopathy. A definitive diagnosis of Lyme’s disease can sometimes be difficult to make, though blood tests may detect antibodies 4 to 6 weeks after the initial infection.


When presented with a case of suspected Lyme’s disease, it’s wise to treat the animal early. Antibiotics, such as tetracyclines, doxycycline or penicillin derivatives are all effective. A minimum of 7 days treatment is advised, with some cases requiring 2 or more weeks, especially those with persistent signs. It may also be necessary to give additional support to organ systems if they’ve been affected. Whist most cases recover well and have an excellent prognosis, some will experience lifelong joint pain. Infection in some animals may continue despite the use of antibiotics and may need further investigation.

Can Lyme disease be prevented?

The key to preventing Lyme disease is to tackle the ticks that transmit the disease. We need to be vigilant and act to both prevent tick bites and remove them.

The main tick that carries the infective agent Borrelia is the sheep tick, Ixodes ricinus. These ticks are mainly a problem during the warm wet months of the year and are most often found during the spring and autumn.

Encourage regular tick checks

During the high-risk times of year, owners should check their pet daily to reduce the risk of infection.

  • Sub-adult ticks can be very small (1mm of so in size).
  • Stroking the pet is an ideal time to do a fingertip search.
  • Brush or comb the coat to look for any ticks that are close to the skin.
  • Backcombing is a good way to see the roots.
  • Check around the ears, eyes, chin, muzzle and feet.

What tick treatments are available?

There are a number of products licensed in the UK for tick control on dogs and cats. 3 examples of popular treatments are;

1. Spot on treatments – they usually contain one of the following ingredients;

2. Tablets – chewable tablets containing fluralaner. They’re safe and effective.

3. Collars – there are some very effective collars available as well, which have the active ingredients impregnated into the material of the collar. The ingredients are usually one of the following