Light micrograph showing Borrelia burgdorferi bacteria, the cause of Lyme disease in a sample of heart tissue processed with Warthin-Starry stain. These spirochaete (spiral-shaped) bacteria are passed to humans through the bites of infected Ixodes sp. ticks. Symptoms of Lyme disease include skin lesions, muscle pain, neurological and cardiac abnormalities, and arthritis. Treatments include antibiotic and corticosteroid drugs.