Orientia, Ehrlichia, Anaplasma, Coxiella Flashcards
What causes scrub typhus?
Orientia Tsutsugamushi
What is the clinical presentation of scrub typhus?
Fever, HA, maculopapular rash after 5 days
Lymphadenopathy
NEcrotic eschar at bite site
Where is scrub typhus found and what is the transmission vector?
Far East
Mites
What is the treatment for scrub typhus?
Tetracycline, chloramphenicol, doxycycline
Can also not treat-> fever goes away within 2-3 weeks
What causes Erlichiosis?
Human Anaplasmosis (HA): Anaplasma Phagocytophilum, Ehrlichia Ewingii
Human Monocyte Erlichiosis (HME): Ehrlichia chaffeensis
Whats the difference between the HA and HME forms of ehrlichiosis?
HA: bacteria grows inside GRANULOCYTES and transmitted to humans via tick and rodents
HME: infects and multiplies inside MONOCYTES with tick as vector and deer as reservoir
What is the clinical presentation of Ehrlichiosis?
Flu like illness: fever, HA, myalgia
Onset 1-2 weeks after tick bite
Generally no rash: EXCEPT: HME shows late onset rash
Leukopenia, thrombocytopenia, inc serum transaminases
Describe the pathogenesis of ehrlichiosis
Bacteria infects circulating leukocytes (no peptidoglycan or LPS) -> multiply within inclusions-> prevents lysosomal fusion -. growth until lysis of host cells
What are the 2 forms of inclusions?
Elementary bodies -> assemble into morulae
Reticulate bodies
How is ehrlichiosis diagnosed?
Morulae detection
PCR
IFA for confirmation
How is ehrlichiosis treated?
Doxycycline
Rifampin for prengant women
Which abx are not effective for ehrlichiosis
Chloramphenicols, penicillins, macrolides
What causes Q fever?
Coxiella Burnetii
What is the clinical presentation of Q fever?
NO RASH
Mild, dry hacking cough and pneumonia
9-20 days: abrupt onset of fever, chills, HA
What can be seen with chronic Q fever?
Subacute endocarditis
