The Pulse Of Veterinary Medicine
Vet-To-Vet Conversation With IDEXX
Non-profit health organization warns that Alabama’s mild winter will mean more ticks this season, and underscores that people whose pets have Lyme disease are at greater risk of contracting the disease.
Lyme disease, caused by the bacterium Borrelia burgdorferi, is transmitted by the deer tick (Ixodes scapularis) and the western black-legged tick (Ixodes pacificus), both of which can also transmit anaplasmosis. Lyme disease has the highest prevalence in the Northeast, Midwest and West Coast. However, due to expanding ranges of the tick vectors along with pet travel, it has now been found throughout North America. The Companion Animal Parasite Council (CAPC) recommends that every pet be tested regularly and protected year-round from all vector-borne diseases, not just Lyme disease. An annual screening protocol that includes the SNAP® 4Dx® Plus Test allows you to recognize changing prevalence in your region, detect and treat co-infections, and measure the efficacy of preventative protocols.
Prevention of Lyme disease is primarily focused on preventing bites from infected ticks, although vaccines are also available that may help prevent transmission and the development of clinical disease. The many options for tick control include topical spot-on treatments, tick-repellant collars, and oral acaricides. In addition, landscape management and careful examination for and removal of ticks are recommended to help prevent transmission of vector-borne diseases.
Clinical signs of Lyme disease in infected dogs may range from absent or mild to severe. Polyarthritis, potentially with fever, lethargy, and anorexia is a common presentation in Lyme disease. Rapidly-progressive protein-losing nephropathy with renal failure and neurologic syndromes may also be seen as well. Polyarthritis and associated symptoms can also be common signs of other vector-borne diseases, such as anaplasmosis. Neurologic signs, uveitis, and immune-mediated hemolytic anemia or thrombocytopenia are significant potential complications of rickettsial infections. Dogs co-infected with B. burgdorferi and Anaplasma phagocytophilum may have two times the risk of developing clinical disease. In addition, they may have more complex disease presentations and slower response to therapy.
Clinical signs in Lyme disease often appear weeks to months after initial infection. By the time most dogs present with clinical signs, a strong C6 antibody response has developed. The C6 antibody, detected by the Lab 4Dx® Plus Test and the quantitative Lyme Quant C6® Test, is produced only as a result of Borrelia burgdorferi infection and replication within the mammalian host, and it is therefore specific for infection, not just exposure. Vaccination does not produce a C6 antibody response. Systemic circulation of B. burgdorferi in the peripheral blood is generally not seen in the dog, making detection by PCR on whole blood specimens unlikely. For these reasons, C6 serology is preferred over PCR for detection of Borrelia burgdorferi in sick patients.
In sick dogs with signs consistent with vector-borne diseases, a combination of serology with a comprehensive vector-borne PCR panel is recommended for accurate diagnosis. Clinical signs of other vector-borne diseases such as anaplasmosis, ehrlichiosis, babesiosis, and bartonellosis, may be difficult to distinguish from Lyme disease. Additionally, co-infections can significantly affect the clinical course of disease and prognosis. In contrast to Lyme disease, clinical signs of anaplasmosis usually appear early in infection, prior to seroconversion. At this stage, PCR tests can detect the DNA of the organism with high sensitivity even though antibody tests are often negative. Combining either the Lab 4Dx® Plus Test or the Lyme Quant C6® Antibody Test with the IDEXX Canine Comprehensive Tick/Vector Comprehensive RealPCR™ Panel improves your ability to make a complete and accurate diagnosis and start appropriate treatments earlier.