Rickettsia

Question 1

Rickettsia are ___ (characteristics)

Answer 1

Obligate intracellular, gram negative coccobacilli

Question 2

One difference between Rickettsias and Anaplasmas is that __ escapes the vacuole and lives inside host cytosol, whereas __ stays inside the vacuole

Answer 2

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

Question 3

Patients with rickettsial disease generally have ___ (platelet levels)

Answer 3

Labs for rickettsial diseases generally indicate thrombocytopenia

Question 4

Presentation of rickettsial disease

Answer 4

Fever

Headaches

Myalgias

Question 5

___ is a syndrome caused by Rickettsia rickettsii and is characterized by the usual rickettsial disease presentation + a maculopapular/petechial rash

Answer 5

Rocky Mountain Spotted Fever

Question 6

A characteristic feature of Rickettsia rickettsii infection is __

Answer 6

Maculopapular rash on palms and soles

Question 7

Rocky Mountain Spotted Fever is transmitted by __

Answer 7

Ticks

Question 8

Dx of RMSF (Rickettsia rickettsii infection)

Answer 8

Dx: skin biopsy/PCR + serology

Question 9

Rx of Rocky Mountain Spotted fever

Answer 9

Tetracyclines: Doxycyline/Tetracycline

Question 10

Epidemic typhus is caused by __ and transmitted by lice

Answer 10

Epidemic typhus is caused by Rickettsia prowazekii and transmitted by lice

Question 11

A characteristic feature of Epidemic typhus (Rickettsia prowezaki) infection is __

Answer 11

Lack of rash (like the one you’d see in RMSF)

Question 12

Endemic typhus aka murine typhus, unlike epidemic typhus is transmitted by __

Answer 12

Fleas

Question 13

Characteristic feature of endemic/murine typhus

Answer 13

Lack of rash (like you’d see in RMSF)

Question 14

Complications of endemic/murine typhus (3)

Answer 14

Complications of murine/endemic typhus

CNS/neuropsychiatric problems

Hepato-renal problems

Respiratory failure

Question 15

Dx for endemic and epidemic typhus

Answer 15

Dx: skin biopsy/PCR + serology (might be negative in 1st 2 weeks)

Question 16

Rx for endemic and epidemic typhus

Answer 16

Tetracyclines (esp doxycycline)

Alt: FQs – Ciprofloxacin; Chloramphenicol; Also delousing

Question 17

___ is caused by Orientia tsutsugamushi and is transmitted by mites (aka chiggers)

Answer 17

Scrub typhus

Question 18

50% of people with Orienta tsutsugamushi/Scrub typhus infection have characteristic ___

Answer 18

Eschars (mite larvae bites)

Question 19

2 main complication of severe scrub typhus are __

Answer 19

Pneumonia

Renal failure

Question 20

Rx for Scrub typhus

Answer 20

adults: (tetracyclines) doxycycline, tetracycline
children: (tetracyclines) doxycycline, tetracycline or chloramphenicol

Question 21

Anaplasma spp like to live inside __(cell type)

Answer 21

Hematopoietic phagocytic cells

Question 22

Human monocytic ehrlichiosis (HME) is caused by ___

Human granulocytic anaplasmosis (HGA) is caused by ___

Answer 22

Ehrlichia chaffeensis

Anaplasma phagocytophilum

**MEGA:

M-E: erlichia will be in monocytes + macrophages

G-A: anaplasma likes to be in GrAnulocytes like neutrophils

Question 23

Common features between Ehrlichia and Anaplasma

Answer 23

Gram negative cell wall

No LPS/peptidoglycan

No metabolic pathways

Question 24

Risk factors for Ehrlichia + Anaplasma infection:

Answer 24

Being male

Age (more cholesterol for these things to feed on)

Question 25

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

Answer 25

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)

Question 26

Presentation/Lab findings for Anaplasma and Ehrlichia infection

Answer 26

(same as the others, no rash really) Thrombocytopenia and liver problems

Question 27

Dx of HME and HGA

Answer 27

Blood smear PCR Serology

Question 28

Rx for HME and HGA

Answer 28

Tetracyclines (doxy + tetra) \*if pt pregaz, give rifampin\* Alternative: FQ's