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Background:
Lyme disease is an infection caused by Borrelia burgdorferi, a bacteria that is transmitted to humans by ticks. It can cause many different symptoms including rash, fever, headache, meningitis (infection of the central nervous system), and arthritis. While most patients improve after taking antibiotics, some patients continue to have symptoms. It is currently unknown why some patients continue to have symptoms. One possibility is that the antibiotics have not successfully gotten rid of all of the bacteria. Current tests for Lyme disease cannot tell whether the bacteria have been successfully eliminated from the body.
Xenodiagnosis is a way to look for Borrelia bacteria using the animal that usually hosts them, Ixodes scapularis (also known as the deer tick). This method takes advantage of the evolution of the bacteria and the insect that transmits the infection, which can make the insect particularly good at finding the agent. In studies of animals, xenodiagnosis may be more sensitive than current tests for detecting the presence of the Lyme disease bacteria. Researchers are interested in using xenodiagnosis to determine whether uninfected ticks that feed on humans who have been infected with Lyme disease bacteria can detect the continued presence of live bacteria.
Objectives:
- To determine whether xenodiagnosis can be used to successfully investigate the presence of Lyme disease bacteria.
Eligibility:
Design:
Full description
Lyme disease is the most common vector borne disease in the United States. Although antibiotic therapy is clinically effective in treating the symptoms of Lyme disease for most patients early in the course of disease, a significant number of patients who receive therapy report persistent symptoms. The cause of persistent symptoms after antibiotic therapy for Lyme disease is an area of great controversy. Recent studies have shown that the organism (Borrelia burgdorferi) may persist in animals after antibiotic therapy and can be detected by using the natural tick vector (Ixodes scapularis) to acquire the organism through feeding (xenodiagnosis). Whether this occurs in humans is unknown. Currently available tests for human Lyme disease do not allow determination of persistent infection after antibiotic therapy.
In this proposal, the utility of xenodiagnosis for identifying persistence of B. burgdorferi in treated human Lyme disease will be tested in up to 120 subjects with various stages of Lyme disease with 30 healthy adults to serve as controls. Subjects will be followed for approximately 3 months. In Objective #1, subjects who have the characteristic erythema migrans (EM) rash and have been treated with antibiotics early (within 3 weeks of infection) in the course of Lyme disease will be tested. After completion of antibiotic therapy, 25-30 larval Ixodes ticks will be allowed to feed on the subject and biopsies of the EM site will be performed. Repleted ticks will be collected and tested for the presence of B. burgdorferi. In Objective #2, similar studies will be performed, but enrollment will target subjects with elevated C6 (region 6 of the VlsE surface protein of B. burgdorferi) antibody levels. In Objective #3, patients with persistent symptoms after antibiotic therapy will be evaluated. As an attempt to increase the chances of a positive xenodiagnosis in humans, patients with EM who are in the first 2 days of antibiotic therapy and patients with untreated Lyme arthritis will also be evaluated. Evidence that B. burgdorferi can be recovered by xenodiagnosis after antibiotic therapy in subjects with continued symptoms would change the current paradigm for potential mechanisms of disease and provide researchers and clinicians a tool for identifying patients with persistent infection. In Objective #4 we will assess the safety of the planned xenodiagnostic procedure in humans. All individuals who underwent xenodiagnosis under the study will be assessed for adverse events.
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Inclusion and exclusion criteria
Criteria for the diagnosis of Lyme disease can be found at The clinical assessment, treatment, and prevention of Lyme disease, human granulocytic anaplasmosis, and babesiosis: clinical practice guidelines by the Infectious Diseases Society of America (4).
Patients With EM (N=35), Post Treatment
High C6 Antibody Titer (N=35)
Post Lyme disease syndrome (N=20)
Patients With EM (N=20), On Treatment
Lyme Arthritis (N=10)
Healthy Volunteers (N=30)
EXCLUSION CRITERIA:
EXCLUSION FROM SKIN BIOPSY PART OF THE PROTOCOL:
Primary purpose
Allocation
Interventional model
Masking
45 participants in 1 patient group
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Data sourced from clinicaltrials.gov
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