Laboratory Diagnosis of Tick-Borne Infections
Part 2
Phylogenetic Tree
July 2010
This prompted us to perform some additional testing including sequencing of the amplified DNA from this sample and then compare it to sequences of other closely related organisms which allowed us to produce this phylogenetic tree showing that the organism is a novel ehrlichiosis agent that is most closely related to Ehrlichia muris, a mouse pathogen. We aretherefore calling this an Ehrlichia muris-like organism or EML. And this organism has never previously been identified from humans in North America. You can see that it is distinct from other causes of human ehrlichiosis and anaplasmosis, including Ehrlichia chaffeensis, Ehrlichia ewingii, and Anaplasma phagocytophilum. So this was an unexpected and very interesting discovery.
Phylogenetic Tree |
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?
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