Rickettsia

Question 1

Rickettsia general facts (8)

Answer 1

Obligate intracellular parasites
DNA/RNA
multiply in cytoplasm
Rod to coccoid shape
Can make ATP
Transmitted by arthropod vectors
Nonmotile
Proliferate in endothelial lining of BV's-hallmark Rash

Question 2

Types of Rickettsia

and 3 others

Answer 2

Rickettsia rickettsii
Rickettsia atari
Rickettsia prowazekii
Rickettsia typhi
Orienta tsutsugamushi

Ehrliche and anaplasma
Coxiella burnetti

Question 3

Differential

• Rash
• Leuko/Neutropenia
• Morula
• vasculaitis

Answer 3

Rash

• 90% RMSF-50% petichae
• HME 50%

Leukopenia-HME, Neutropenia-HGA

Morulae-rarely HME (macro/mono), occasionally HGA (neutro)

Vasculitis-RMSF hallmark

Question 4

Rickettsia rickettsii
group
-Clinical characteristics
-transmission
-ID
-Trx

Answer 4

Rickets’s Rock Climbing Competition
spotted fever group
-RMSF-attach to host OmpA/B on endothelial cell, phagocytosis, escape phagosome and porfilerate in host cytoplasm-actin propulsion to other cells, pethaciael rash, rash own palms and soles to trunk, fever, myalgia, headache
-Dog tick or Rocky Mountain wood tick or Dermacentor tick-vector/resoivoir
-Serologica tests
-Doxyclyclin

Question 5

Rickettsia akari
group
-Clinical characteristics
-transmission
-ID
-Trx

Answer 5

spotted fever group

• Rickettsial pox-primary papule at bite which ulcerates into dark eschar-spreads to generalizes rash that is not on palms and soles, chills, fever, headache—targets macrophages/monocytes-Not endothelial cell
• mouse mite bite
• biochem test, serologically cross reactive with ricket rickettsii
• probably doxy

Question 6

Rickettsia prowazekii
group
-Clinical characteristics
-transmission
-ID
-Trx
-special

Answer 6

Pro Boot Camp
Typhus group
-Louse borne typhus (epidemic)-inter blood stream through endothelial cells, phagocysed, escape phagosome and proliferate till cell bursts–fever chills, rash from trunk to amenities without palms, soles, or face…Brill-Zinsser is recrudescent form from stress or immunocomp
-human louse feces (human is host), lice/flea feces, flying squirrels
-biochem test
-doxy
-replicates in louse gut epi until burst, extracellular form in louse feces

Question 7

Rickettsia type
group
-Clinical characteristics
-transmission
-ID
-Trx

Answer 7

typhus

• Murine typhus-endemic-higher fever, headache, scab at bite site, can be asymptomatic and infectious for long time
• rat is reservoir, flea is vector
• biochem test-only in subtropic subcostal regions (South texas/socal in US)
• prob doxy

Question 8

Orienta tsutsugamushi
group
-Clinical characteristics
-transmission
-ID
-Trx

Answer 8

typhus

• scrub typhus-high fever, headache, scab at bite, rash
• Mice mite/chiggger is reservoir
• Far east

Question 9

Ehrliche and Anaplasma

Answer 9

Erlicha-mono and macro, anaplasma neutrophils
tick borne
multiply within PM vesicle known as morula

HME and HGA

Question 10

Coxiella burnetti

Answer 10

Gran negative
No rash
Obligate intracellular organism
Farm animals-spores in GI of animals to feces
-aerosol transmission–usually farmers or vets

Q fever-pneumonia, headache hepatitis

• suually self limiting
• endocarditis in immunocomp patients

Question 11

HME

Answer 11

Human monocytic ehrlichosis
-Southeast and S central US, ticks as vector (not Ixodes scapularis), deer is host, leukopenia, thrombocytopenia, fever, headache

Question 12

HGA

Answer 12

Human Granulocyte Anaplasmosis

-Ixodes scapulars is vector, white foot mouse is host, more, fever, headache, myalgia, bone marrow/spleen problems