A hiker returns from the northeastern United States with fever, headache, and an expanding annular plaque with central clearing on the thigh. Which combination correctly identifies the vector and the preferred oral therapy for this stage of disease in adults?

• A Ixodes tick, doxycycline ✓
• B Ornithodoros tick, penicillin G
• C Amblyomma tick, ceftriaxone
• D Rhipicephalus tick, chloramphenicol

Explanation

Early localised Lyme disease with erythema migrans is acquired from the bite of Ixodes ticks transmitting Borrelia burgdorferi, and in adults it is treated orally with doxycycline for 10 to 14 days. Ceftriaxone intravenously is reserved for carditis, meningitis, and arthritis. Ornithodoros transmits relapsing fever borreliosis, and Amblyomma and Rhipicephalus are vectors of other rickettsioses, not Lyme disease.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.