Laboratory Diagnosis of Tick-Borne Infections

Potential Roles for PCR

July 2010

This case nicely demonstrates some potential roles for PCR in the diagnosis of Lyme disease; specifically that it may facilitate diagnosis of early infection before a serologic response is detectable. It’s also useful for confirmation of active disease in a previously infected patient who has a positive serology, and this is actually quite important in endemic areas because it is not uncommon for individuals to have a detectable serologic response due to previous disease which may have even been asymptomatic, whereas Borrelia burgdorferi DNA would only be detected in active infection. PCR can also be useful for diagnosis of an atypical rash when tissue from a skin biopsy of the rash is tested. And it can be used for confirmation of neuroborreliosis (especially early disease), and Lyme arthritis. In fact, many different types of specimens can be tested for Lyme PCR.

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Potential Roles for PCR

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Jump to section:

• Introduction
• Presentation Outline
• Tick-Borne Diseases
• Advantages and Limitations of Conventional Tests
• Molecular Diagnostic Methods Potential Advantages
• Molecular Diagnostic Methods Potential Disadvantages
• Treatment and Diagnostic Recommendations
• Case 1
• Diagnostic Workup
• Representative Image Giemsa-stained Peripheral Blood Smear
• Differential Diagnosis
• Which one is Plasmodium falciparum?
• Main Morphologic Features Table
• Classic Maltese Cross
• Extracellular Forms of Babesiosis
• Side-by-Side Comparison
• Further Workup
• Malaria PCR
• Babesia microti PCR
• Advantages/Uses of PCR
• Potential Disadvantages
• Potential Disadvantages
• Case 2
• Lyme Disease: Diagnostic Approach
• Reported Cases of Lyme Disease, 2008
• Serologic Assay: Test of Choice for Diagnosis of Lyme Disease
• Case 2, Further Workup
• Potential Roles for PCR
• Which Specimens Should be Tested by PCR?
• PCR for Detection of Borrelia burgdorferi DNA in Blood
• Case 3
• Live Tick Image
• Tick Image Close Up
• IDSA Guidelines
• IDSA Guidelines, continued
• Testing of Ticks by PCR
• Case 4
• Tick-Borne PCR Panel
• Diagnostic Tests for HME and HGA
• PCR for Diagnosis of Ehrlichiosis/Anaplasmosis
• Ehrlichia and Anaplasma PCR Assay Graph
• Phylogenetic Tree
• Ehrlichia muris-like Organism
• All Patients with EML had Tick Exposure
• Prevention of Tick-Borne Diseases
• Conclusions
• Conclusions, continued
• Questions?