Borreliosis in Dogs
(Canine Lyme Disease)
Clinical Signs & Symptoms
Subclinical infection is common in dogs. When chronic infection does develop in individual dogs, it may persist for several years. In addition, re-infection or co-infections with other tick-transmitted organisms may occur. When clinical disease occurs, the most common signs are:
- Lethargy (weakness / loss of energy)
- Anorexia (loss of appetite leading to weight loss)
- Pyrexia (fever)
- Inflammatory arthritis - maybe mono- or polyarthritis (single or multiple joint involvement)
- Lymphadenopathy (swollen / enlarged lymph nodes)
Renal, cardiac, and neurologic forms of the disease are characterised by clinical and laboratory abnormalities. Renal Borreliosis in canine syndrome is generally fatal. It is characterised by uremia, hyperphospataemia, and severe protein-losing neuropathy, often accompanied by peripheral oedema. In the rare cardiac form, conduction abnormalities with bradycardia occurs. In the neurologic form, paralysis and seizure disorders have been reported.
There is little information available regarding incubation periods for naturally infected dogs. However, joint disease following experimentally-induced infection presents after two to five months. The first episode of arthritis is generally in the limb closest to the tick bite. In untreated or inadequately treated dogs, episodes of arthritis and lameness may be recurrent. The different species of Borrelia bacteria may induce differing clinical signs.
Diagnosis
There is still debate within the veterinary community as to what constitutes a definitive diagnosis of canine Borreliosis. This is because of the subjectivity of criteria used in defining the naturally occurring disease. However, history of tick exposure and/or tick attachment, compatible signs combined with a positive test or rising titre for antibodies, and the animal's response to appropriate antibacterial agents are the most useful clinical criteria.
Clinical laboratory findings are non-specific for canine Borreliosis. Abnormalities present on the haemogram, biochemical profiles and urinalysis may include:
- An inflammatory leukogram
- Renal azotemia
- Hypoalbuminemia
- Proteinuria
- An inflammatory urine sediment
Joint fluid changes include an increase in cell counts that consist primarily of a neutrophilic response. Organisms have been identified in peripheral blood, urine, joint and CSF fluids by use of dark-field or phase-contrast microscopy in naturally and experimentally infected dogs, but these techniques are not generally used in clinical practice.
Diagnostic Tests
Indirect fluorescent antibody (IFA) assay, enzyme-linked immunosorbent assay (ELISA), or characteristic serum proteins analysis (Western blot technique).
Serology is the mainstay for confirming a clinical impression of Lyme disease. However, asymptomatic dogs in endemic areas may often be seropositive. Another limitation is that animals can take some time to seroconvert following infection. Therefore, many early cases can return a negative result on serology. Animals may also remain seropositive for a long time following treatment, making it difficult to determine whether a successful resolution has been achieved.
Many veterinarians consider the specific C6-based assay to be the initial screening method of choice for evaluating a dog for exposure to, and potentially infection with, Borrelia burgdorferi.
Treatment
The standard treatment for disease in dogs is Doxycycline PO @ 10mg/kg q24h for 30 days. However, this duration of therapy is not supported by studies involving the treatment of dogs that were experimentally infected. Two different experimental studies have revealed that a 30-day course of therapy with Amoxicillin, Doxycycline, Ceftriaxone and Azithromycin failed to eliminate infection, though it did reduce the ability of investigators to isolate the organism from tissues. Longer courses of treatment may be necessary, particularly in dogs with neuropathy.
Antibiotic treatment of clinically normal but seropositive dogs is controversial. Many seropositive dogs do display evidence of clinical disease. However, because the course of infection can be prolonged, treating in the subclinical phase is viewed by some veterinarians as potentially beneficial in preventing the development of chronic disease.
Medical Abbreviations
I.V. |
= |
intravenous |
I.M. |
= |
intramuscular |
P.O |
= |
by mouth |
q8h |
= |
every 8 hours |
q12h |
= |
every 12 hours |
q24h |
= |
every 24 hours |
Vaccines
There is currently no vaccine against Borreliosis for dogs in the UK.
