Lyme disease

Borrelia

Borrelia burgdorferi sensu stricto Borrelia garinii Borrelia afzelii

Life cycle of ticks

Life cycle of ticks

Two adult deer ticks

Ticks are pretty small…

Stage one (early infection)

Erythema migrans

• 3 days to 1 month following bite

• Occurs in 60-80% (ie doesn’t always occur)

• Expands to characteristic “bulls eye”

Stage one (early infection)

Not all rashes are Lyme disease

• Allergic reactions to tick saliva usually occur within hours to a few days after the tick bite, usually do not expand, and disappear within a few days.

• Erythema migrans persists longer, but usually subsides within 3-4 weeks.

Stage two (dissemination stage)

• Fatigue • Fever • Headache • Muscle and joint pain • Lymphadenopathy• Secondary annular skin lesions

Stage three (persistent infection)

• Months or years following bite• Typically involves intermittent episodes of

joint pain• Meningitis• Bell's palsy, numbness, pain• Cardiac arrhythmias• Migratory pain to joints, tendons, muscle

and bone.

Stage three (persistent infection)

• RheumatologicalChronic Lyme arthritis in11% - erosion of cartilage and/or bone

• NeurologicalDepression, disturbances in memory, mood, or sleep patterns, tingling, numbness

Diagnosis• Serodiagnosis to detect anti-borrelia

antibodies is not useful until in later stages of illness.

• B. burgdorferi can be cultured from 80% or more of biopsy specimens taken from early erythema migrans lesions. However, the diagnostic value of this procedure is limited because of the need for special bacteriologic media (BSK medium) and protracted observation of cultures.

Treatment

• Doxycycline

• Late treatment can result in persistent symptoms

Prevention• Avoid tick-infested areas, especially in May, June,

and July• Insect repellent containing DEET• Wear a hat and a long-sleeved shirt• Walk in the centre of trails to avoid overhanging

grass and brush.• After being outdoors, remove clothing and wash

and dry it at a high temperature• Remove ticks• Preventive antibiotic treatment with erythromycin

or doxycycline?

Summary

• A third of patients don’t have a rash• Stage 2 symptoms are vague• Stage 3 consequences are serious• Diagnosis is difficult• Awareness of the disease is poor