53 112 Definition A tick-borne spirochetal disease caused by the bacterium Borrelia burgdorferi is endemic in several areas of the United States, including the upper-Atlantic, upper north–central regions, and northern California. The organism is introduced into the skin of a susceptible host by an infected deer tick. It was named after the town in Connecticut where a cluster of children with arthritis was found. Characteristics Lyme disease is diagnosed primarily by employee’s knowledge of a tick bite or detection of a rash on physical examination. Nearly 50 percent of treated patients will have minor latent symptoms, such as headache, musculoskeletal pain, facial palsy, or lethargy, and major la- tent complications will occur in fewer than 10 percent. The agent Borrelia burgdorferi is transmitted by very small ticks, primarily the ixodid tick, from the host (deer or mice), and antibodies to this agent appear weeks to months after infection. Testing before 4 to 6 weeks is not reliable. Diagnosis and treatment of Lyme disease in its primary stage can reduce the chances of developing secondary and tertiary disease symptoms. Early treatment of the pri- mary disease might reduce or abort the antibody response to the organism but not eliminate the late manifestations of infection. Immune response might be detectable by lymphocyte proliferation or Western blot assay, but these tests are not available widely thus, serological diagnosis might be unreliable. Primary or early localized Lyme disease. The period between the tick bite and the onset of the primary disease varies from 3 to 32 days. Erythema chronicum migrans, a rash with an erythematous border and a clearing center that can expand to become very large and warm but painless, is exhibited. Flulike symptoms, intermittent low-grade fever, chills, malaise, stiff neck, arthralgias, and headache often are manifested. In most patients, the lesion fades, and primary symptoms disappear within 3 to 4 weeks. Secondary or early disseminated Lyme disease. This stage occurs within 1 to 6 months after exposure. Signs and symptoms include severe lethargy, encephalopathy, myalgias, arthritis, depression, generalized lymphadenopathy, and splenomegaly. Skin symptoms include lym- phocytoma, a solitary red or violaceous lesion most commonly located on the earlobe in children or the nipple of adults. This stage can produce such neurological complications as meningitis, cranial nerve palsies, and radiculitis. Meningitis is present in 80 percent of the cases with second-stage neurological disease. Tertiary or late Lyme disease. Without antibiotic treatment, more severe symptoms occur within weeks to months (or even years) after the primary infection. Signs and symptoms in- clude chronic skin changes exhibited by insidious changes on the distal portions of the ex- tremities, with pain, redness and swelling. Arthritis symptoms occur in large joints and usually are asymmetrical. Nervous system involvement can occur, including memory loss and difficulty concentrating. Chronic meningoencephalitis might result in multiple sclerosis and generalized polyneuropathy. Policy Evaluate the employee in the occupational health unit who presents with signs and symp- toms of Lyme disease and refer for medical treatment. Lyme Disease Guideline continues on next page