What are the criteria for diagnosing Lyme disease?
We consider four criteria important in establishing the diagnosis of Lyme disease in dogs: • History of exposure to ticks in an endemic area. • Typical clinical signs (lameness with or without fever). • A positive antibody test. • A prompt response to antibiotic therapy. One or two of these criteria alone are usually not sufficient to confirm a diagnosis. For example, if a dog has never been in an area known to be infected with Ixodes ticks carrying B. burgdorferi, it is very unlikely that the dog will have Lyme disease. A diagnosis based on clinical signs often remains questionable, for there are several other conditions, such as immune-mediated disease and rheumatoid arthritis, that cause lameness and pain in dogs. A positive antibody titer alone tells very little. Many dogs with high antibody titers fail to have clinical signs. The presence of a specific type of antibody (IgM) is a good indicator of recent infection with some diseases, but in cases of Lyme disease, IgM antibodies pe
