Lyme Disease and Ticks: Not All Ticks Carry the Bacteria

Only specific tick species transmit Lyme disease, and only a fraction of those are infected.

Primary Vectors

• Blacklegged tick (Ixodes scapularis) – Northeast, Midwest, Mid-Atlantic US.
• Western blacklegged tick (Ixodes pacificus) – Pacific Coast.

Other Potential Vectors (Less Common/Competent)

• Lone star tick (Amblyomma americanum) – associated with STARI, not classic Lyme.
• American dog tick (Dermacentor variabilis) – not a competent Lyme vector.

Infection Risk Factors

• Tick species and life stage: Nymphs (poppy seed size) cause most human cases—abundant spring/summer, hard to see.
• Attachment duration: Transmission typically requires ≥36–48 hours of feeding.
• Local infection prevalence: Varies by county (0–50%+ in nymphs).

Prevention

• Permethrin-treated clothing, DEET/picaridin repellents.
• Tick checks after outdoor activity; shower within 2 hours.
• Prompt removal with fine-tipped tweezers (grasp close to skin, pull steady).
• Monitor for rash (erythema migrans) or flu-like symptoms for 30 days.