What are the diagnostic tests and treatment options for Lyme disease and babesiosis (Babesia microti infection) in patients with a history of tick exposure?

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Last updated: June 24, 2025View editorial policy

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From the Guidelines

Diagnostic testing for Lyme disease and babesiosis should begin with a thorough clinical assessment, and laboratory testing should be guided by the patient's symptoms and history of tick exposure, with a two-tier serological approach for Lyme disease and blood smear examination, PCR, and antibody testing for babesiosis. The most recent and highest quality study 1 recommends a 2-tiered serologic test for Lyme disease, consisting of an enzyme-linked immunoassay (EIA) or immunofluorescence assay (IFA), followed by a reflex Western immunoblot. For babesiosis, diagnosis relies on blood smear examination to identify parasites within red blood cells, PCR testing for Babesia DNA, and antibody testing.

  • Key considerations for Lyme disease diagnosis include:
    • Early localized or disseminated disease: doxycycline 100mg twice daily for 10-21 days is the first-line therapy, with alternatives including amoxicillin 500mg three times daily or cefuroxime axetil 500mg twice daily for the same duration 1.
    • Lyme arthritis: a 28-day course of these antibiotics is recommended.
    • Neurologic Lyme disease: intravenous ceftriaxone 2g daily for 14-28 days may be required.
  • For babesiosis, treatment consists of atovaquone 750mg twice daily plus azithromycin 500mg on day one followed by 250mg daily for 7-10 days, or clindamycin 600mg every 8 hours plus quinine 650mg every 8 hours for 7-10 days, particularly for severe cases 1.
  • Patients with co-infections require treatment for both diseases simultaneously, and prompt treatment is essential to prevent severe complications, especially in immunocompromised or asplenic patients.

From the Research

Diagnostic Tests for Lyme Disease and Babesiosis

  • Lyme disease can be diagnosed using serological tests, such as enzyme immunoassay (EIA) followed by Western blot testing, especially for extracutaneous manifestations 2, 3.
  • For babesiosis, microscopy and polymerase chain reaction (PCR) assay of blood specimens are used to diagnose active infection 4, 3.
  • A multiplex qPCR can be employed for the simultaneous diagnosis of active Lyme disease and babesiosis, with an 80% sensitivity for detection of Lyme disease 5.

Treatment Options for Lyme Disease and Babesiosis

  • Oral doxycycline, amoxicillin, and cefuroxime axetil are effective for treating Lyme disease, with ceftriaxone recommended for parenteral antibiotic therapy 3.
  • A 10-day course of oral doxycycline is effective for treating erythema migrans and early neurologic Lyme disease in ambulatory patients 3.
  • For babesiosis, a 7- to 10-day course of azithromycin plus atovaquone is effective for mild cases, while a 7- to 10-day course of clindamycin plus quinine is often used to treat severe cases 3.
  • In highly immunocompromised patients with babesiosis, a minimum of 6 weeks of antibiotics is recommended, with no parasites detected on blood smear for at least the final 2 weeks of treatment 3.

Considerations for Co-Infections

  • Co-infections with Borrelia burgdorferi and Babesia microti can occur, and diagnosis should be based on detection of the organisms rather than serology 4.
  • Multiplex qPCR can detect co-infections with B. burgdorferi and B. microti, allowing for timely treatment of both diseases 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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