Lyme neuroborreliosis in 2 horses.

The research article discusses two cases of chronic Lyme neuroborreliosis in horses, a condition caused by the bacteria Borrelia burgdorferi, leading to neurologic disease. The bacteria was found in various tissues, with major concentrations in areas of inflammation like spinal cord, muscle, and joint capsule.

Research Objectives and Methods

• The research paper studies Lyme neuroborreliosis, a condition seen as a progressive neurological disease in horses. The condition is caused by the bacteria Borrelia burgdorferi sensu stricto.
• The diagnosis was made by identifying Borrelia burgdorferi sensu stricto using polymerase chain reaction (PCR) amplification. PCR is a method widely used in molecular biology to make copies of a specific DNA segment, which helps in identification of the organism.
• The researchers focused on specific gene targets – ospA, ospC, flaB, dbpA, arp of the bacteria for PCR amplification.

Findings

• The research found that the tissues with inflammation, including spinal cord, muscle, and joint capsule, had the highest concentration of the Borrelia burgdorferi bacteria, indicating that the bacteria tends to colonize areas of inflammation.
• Sequence analysis of the genes ospA, ospC, and flaB showed a 99.9% sequence identity to the respective genes in B burgdorferi strain 297. This strain 297 is isolated from a human case of neuroborreliosis, revealing that the infection in horses is nearly identical at the genetic level to that seen in humans.

Visualization of Spirochetes

• In both horses, the researchers were able to visualize the spirochetes – the type of bacteria responsible for this disease – in the affected tissues using Steiner silver impregnation and immunohistochemistry.
• Most of the spirochetes were found within the dense collagenous tissue of the dura mater and leptomeninges, the layers that cover the brain and spinal cord.