Borreliosis is more commonly known as Lyme disease and is one of the most common tick transmitted diseases in the world.
It was first identified in the town of lyme in Connecticut USA, and is caused by a bacteria called borrelia burgdorferi. In the UK 2-3 % of ticks (most commonly ixodes ricinus) carry the bacteria. Ticks usually become infected as larvae and then remain infected as they develop into nymphs and adults. When these infected ticks feed the bacteria multiply in their gut and over a period of days, migrate to the salivary glands where they may then be transmitted to the animal the tick was feeding on. So infection typically happens after the tick has been attached for 2-3 days. While most dogs can become infected and recover without obvious problems, 5-10% of infected dogs will go on to develop clinical signs. Where clinical signs develop, there may be a delay of 2-5 months from the tick bite and so no recent history of tick bites. When infection leads to disease in dogs, the dominant clinical feature is recurrent lameness due to inflammation of the joints. There may also be a fever, lack of appetite and depression. More serious complications include damage to the kidneys, and rarely, heart or nervous system disease. Kidney disease appears to be more prevalent in Labradors, Retrievers, Shetland Sheepdogs and Bernese Mountain dogs.
A rash often recognised in humans may be seen at the point where the tick was attached, but is rarely seen in dogs. This may be due to the fact that the tick bite often happens 2-5 months before any other signs are seen
Diagnosis can be complicated. Routine blood tests can show an inflammatory response. Specific blood tests can show exposure to the bacteria, but this does not mean the dog has the disease (as 90-95% recover without any treatment). Tests on fluid removed from affected joints can show a typical inflammatory process. Definitive diagnosis may require tests on biopsies taken from the skin or synovial membranes of the joints.
Treatment of Borrelia is with a 4 week course of doxycycline, and improvement should be seen 48 hours after treatment starts. Most animals will be clear after 4 weeks therapy, but a few animals may suffer a relapse then therapy stops. Kidney or heart disease will require separate therapy if they occur.
Prevention generally involves preventing tick bites.
- Daily monitoring for ticks on your pet, and careful removal using a tick hook
- Chemical treatment to kill or repel ticks (tablet, spot on or collar)
There is a vaccination available for Lyme disease in dogs which prevents migration of the bacteria to the salivary gland. Given the low incidence of disease in animals infected (5-10%) and the fact that only about 0.5% of ticks carry the bacteria, we do not at this point recommend routine vaccination, but instead regular tick monitoring and use of tick preventative products.