Rickettsia Flashcards
Rickettsia are ___ (characteristics)
Obligate intracellular, gram negative coccobacilli
One difference between Rickettsias and Anaplasmas is that __ escapes the vacuole and lives inside host cytosol, whereas __ stays inside the vacuole
Rickettsia and Orientia, once phagocytosed, escape the vacuole and replicate inside the host cytosol
Ehrlichia and Anaplasma stay inside the vacuole
**note also that Rickettsias infect endothelial cells whereas Anaplasma infect macrophages and neutrophils
Patients with rickettsial disease generally have ___ (platelet levels)
Labs for rickettsial diseases generally indicate thrombocytopenia
Presentation of rickettsial disease
Fever
Headaches
Myalgias
___ is a syndrome caused by Rickettsia rickettsii and is characterized by the usual rickettsial disease presentation + a maculopapular/petechial rash
Rocky Mountain Spotted Fever
A characteristic feature of Rickettsia rickettsii infection is __
Maculopapular rash on palms and soles
Rocky Mountain Spotted Fever is transmitted by __
Ticks
Dx of RMSF (Rickettsia rickettsii infection)
Dx: skin biopsy/PCR + serology
Rx of Rocky Mountain Spotted fever
Tetracyclines: Doxycyline/Tetracycline
Epidemic typhus is caused by __ and transmitted by lice
Epidemic typhus is caused by Rickettsia prowazekii and transmitted by lice
A characteristic feature of Epidemic typhus (Rickettsia prowezaki) infection is __
Lack of rash (like the one you’d see in RMSF)
Endemic typhus aka murine typhus, unlike epidemic typhus is transmitted by __
Fleas
Characteristic feature of endemic/murine typhus
Lack of rash (like you’d see in RMSF)
Complications of endemic/murine typhus (3)
Complications of murine/endemic typhus
CNS/neuropsychiatric problems
Hepato-renal problems
Respiratory failure
Dx for endemic and epidemic typhus
Dx: skin biopsy/PCR + serology (might be negative in 1st 2 weeks)
Rx for endemic and epidemic typhus
Tetracyclines (esp doxycycline)
Alt: FQs – Ciprofloxacin; Chloramphenicol; Also delousing
___ is caused by Orientia tsutsugamushi and is transmitted by mites (aka chiggers)
Scrub typhus
50% of people with Orienta tsutsugamushi/Scrub typhus infection have characteristic ___
Eschars (mite larvae bites)
2 main complication of severe scrub typhus are __
Pneumonia
Renal failure
Rx for Scrub typhus
adults: (tetracyclines) doxycycline, tetracycline
children: (tetracyclines) doxycycline, tetracycline or chloramphenicol
Anaplasma spp like to live inside __(cell type)
Hematopoietic phagocytic cells
Human monocytic ehrlichiosis (HME) is caused by ___
Human granulocytic anaplasmosis (HGA) is caused by ___
Ehrlichia chaffeensis
Anaplasma phagocytophilum
**MEGA:
M-E: erlichia will be in monocytes + macrophages
G-A: anaplasma likes to be in GrAnulocytes like neutrophils
Common features between Ehrlichia and Anaplasma
Gram negative cell wall
No LPS/peptidoglycan
No metabolic pathways
Risk factors for Ehrlichia + Anaplasma infection:
Being male
Age (more cholesterol for these things to feed on)
Where in the US is HME more common? The disease is transmitted by the __ tick
Where in the US is HGA more common? The disease is transmitted by the __ tick
HME: •south central and southeastern US; vector = A americanum
HGA: northeastern + upper midwest US, Europe, Cali; vector = Ixodes tick (#robin of ixodes #also the same guy for lyme disease)
Presentation/Lab findings for Anaplasma and Ehrlichia infection
(same as the others, no rash really)
Thrombocytopenia and liver problems
Dx of HME and HGA
Blood smear
PCR
Serology
Rx for HME and HGA
Tetracyclines (doxy + tetra)
*if pt pregaz, give rifampin*
Alternative: FQ’s
