Lyme borreliosis in horses

Borrelia is the causative agent of Lyme borreliosis, a bacterial disease which is transmitted through bites from ticks of the genus Ixodes. The gram-negative bacteria are collectively referred to as Borrelia burgdorferi sensu lato. In this group, the genospecies Borrelia burgdorferi sensu stricto, Borrelia garinii and Borrelia afzelii are pathogenic for dogs and horses. Whereas in the U.S. only B. burgdorferi sensu stricto is relevant, more than 80 % of Borrelia in European ticks belong to the pathogenic genospecies B. garinii or B. afzelii. Dogs and horses have a significantly increased risk of infection because of their higher frequency of contact with ticks. Most of the infections, however, proceed asymptomatically. Infection does not confer strong immunity. Reinfection is therefore possible. Antibodies against B. burgdorferi can be found in the serum of specifically infected or vaccinated animals. An infection with B. burgdorferi is associated with a variety of clinical symptoms, which generally occur weeks or months after infection.

Borreliosis in horses is characterised by arthritis, alternating lamenesses, algesic muscles, uveitis, encephalitis, miscarriage, fever and lethargy. A vaccine for horses has recently been brought onto the market.

Erythema migrans, a characteristic sign of borreliosis in humans, is not relevant in either dogs or horses since it cannot be seen through the fur or because of dark skin.

Diagnosis of canine or equine borreliosis is based on clinical symptoms, differential diagnostics and the detection of antibodies against Borrelia antigens. Some studies recommend a two-step strategy for the determination of Borrelia-specific antibodies. Firstly, a sensitive screening test (ELISA or IIFT) is used. Sera with a positive or borderline screening result are investigated further using an immunoblot to differentiate between Borrelia-specific and unspecific reactions. Since antibodies against Borrelia are first produced two to six weeks after infection, serological tests performed in the early stage of Lyme borreliosis can be negative. A follow-up sample taken after seven to ten days should therefore be tested in suspected cases. IgM antibodies against Borrelia antigens can be found for a period of a few weeks in the early stage of infection.

• Anti-Borrelia ELISA Horse (IgG)
• Anti-Borrelia EUROLINE Horse (IgG)