Rickettsia and Related Microbes

Question 1

What is the general information about Rickettsia?

Answer 1

Gram negative rods, obligate intracellular bacteria

Question 2

Can Rickettsia be cultured on agar media?

Answer 2

Nope

Question 3

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| What are the 3 phyla of Rickettsia and related microbes?</p>

Answer 3

<p>

| Rickettsia (vector-borne), Ehrlichia (vector), Coxiella (non vector-borne)</p>

Question 4

In general, how is the diagnosis of a Rickettsia organism made?

Answer 4

Pt presentation and history (travel/exposure), confirm with serology

Question 5

What drug are the Rickettsia and others responsive to?

Answer 5

Doxycycline

Question 6

What is the classic presentation of Rickettsia?

Answer 6

Fever, Headache, Rash

Question 7

Where do Rickettsia replicated? In which Cells? What does this cause?

Answer 7

In cytoplasm of endothelial and muscle cells of small blood vessels, hemorrhage and edema, dz is vasculitis leading to rash and headache

Question 8

What is responsible for Rocky Mountain Spotted Fever?

Answer 8

R. Rickettsia

Question 9

How is R. Rickettsia transmitted?

Answer 9

Various ticks (microbes replicate in salivary gland). So it is seasonal, when ticks are active

Question 10

Where is the highest incidence of R. Rickettsia?

Answer 10

NC, SC, AR, MO, OK, TN (endemic in TN)

Question 11

What are initial symptoms of R. Rickettsia?

Answer 11

FLS with severe headache followed by rash, also, significant muscle tenderness (calf)

Question 12

Where is the rash of RMSF?

Answer 12

Spreads from ankles and wrists to soles, palms, and trunk

Question 13

What happens when the rash of RMSF spreads?

Answer 13

Infection becomes systemic…septicemia… DIC

Question 14

How is the Dx of RSMF made?

Answer 14

Initially made on presnetation and Hx, nonspecific Weil-Felix serologic test measures x-reactivity of Anti-rickettsial Ab’s to Proteus OX strains; must confirm by comparison of acute and convalescent sera. Indirect fluorescent Ab assay now used mostly

Question 15

How many people die of RSMF if untreated? What is Tx?

Answer 15

1 in 4; Doxy within first week; septicemia often mistreated with beta-lactams which doesnt work

Question 16

How do you prevent RMSF?

Answer 16

Use DEET to avoid tick bites or remove tick within 4 hours of bite

Question 17

What does R. prowazekii cause?

Answer 17

Epidemic typhus; dz associated with wars and poverty

Question 18

Is R. Prowazekii a zoonosis?

Answer 18

nope

Question 19

How is Epidemic Typhus transferred?

Answer 19

Human to human via body lice

Question 20

Epidemic typhus is similar to RMSF, so how do you distinguish them?

Answer 20

It spreads from trunk to extremities instead of the other way around

Question 21

What are the two bugs classified as Ehrlichia?

Answer 21

E. Chaffeensis (HME) and Anaplasma phagocytophilia (HGA)

Question 22

How are HME and HGA transmitted?

Answer 22

Ticks, but not the same as RMSF geography

Question 23

What cell does R. Chaffeensis replicate in?

Answer 23

Monocytes

Question 24

What cell does A. phagocytophilia replicate in?

Answer 24

Granulocytes

Question 25

Replicating microbes from inclusion bodies in monocytes/granulocytes from HMA/HGA are called what?

Answer 25

Morulae

Question 26

What are the symptoms of HME/HGA?

Answer 26

generally more mild than RMSF; FLS's, and rash is less common

Question 27

Do HMA/HGA bugs have a Weil-Felix reaction?

Answer 27

No

Question 28

How is E. Chaffeensis transmitted?

Answer 28

Lone star deer tick

Question 29

How is the diagnosis of E. Chaffeensis made?

Answer 29

Wright/Giemsa stain of blood smear shows morulae in monocytes and serology

Question 30

How do you treat both E. Chaffeensis and A. Phagocytophilia?

Answer 30

Doxy

Question 31

What is the nickname for the dz caused by A. Phago?

Answer 31

Rocky Mountain SpotLESS fever because rash is so rare

Question 32

How is A. Phago transmitted?

Answer 32

Ixodes deer tick

Question 33

How is Dx of A. Phago made?

Answer 33

Wright/Giemsa stain of blood smear shows morular in granulocytes + serology

Question 34

What is the shape of Borrelia?

Answer 34

Spirochetes

Question 35

How can spirochetes of Borrelia be seen?

Answer 35

Wright/Giemsa stain

Question 36

What characteristic plays a role in relapsing fever of Borrelia?

Answer 36

Antigenic variation

Question 37

What is the causative agent of Lyme Dz?

Answer 37

B. Burgdorferi

Question 38

How is LD transmitted to humans?

Answer 38

Via ixodes deer tick nymph which is extremely small and hard to detect

Question 39

How can one prevent LD?

Answer 39

Remove tick within 24 hours

Question 40

True or False, LD is the most common tickborne dz in the US?

Answer 40

True

Question 41

Where is LD endemic?

Answer 41

New England, Mid Atlantic states, Upper midwest, also in TN

Question 42

What are the early LD symptoms?

Answer 42

FLS usually milder than RMSF, classic bulls eye rash at site of tick bite called erythema chronicum migrans (not always seen)

Question 43

What are the secondary LD symptoms (disseminated)

Answer 43

Arthritis, facial palsy, peripheral neuropathy. Occurs weeks or months after initial infection

Question 44

How is the Dx of LD made?

Answer 44

2 step serological testing: ELISA + Western Blot. PCR based NAATs now available

Question 45

What is the Tx for early LD?

Answer 45

Doxy or Amoxicillin

Question 46

What is the Tx for chronic Ld?

Answer 46

IV Cephalosporins for extended periods

Question 47

What are the causative agents of Relapsing Fever?

Answer 47

B. Hermsii and B. Revurrentis

Question 48

How is B. Hermsii transmitted?

Answer 48

Tick

Question 49

How is B. Recurrentis transmitted?

Answer 49

Louse

Question 50

Where is B Hermsii endemic?

Answer 50

HIgh, dry areas of Western US

Question 51

Is B. recurrentis common or rare in the US?

Answer 51

Rare

Question 52

What are the symptoms of Relapsing Fever?

Answer 52

Recurrent fever that is on one week, off two, rash uncommon

Question 53

How can one see B. Hermsii or Recurrentis?

Answer 53

Wright/Giemsa stain of blood smear

Question 54

What is needed to confirm Dx of relapsing fever?

Answer 54

Serology

Question 55

What is the tx for relapsing fever?

Answer 55

Doxy

Question 56

What is the causative agent of Leptospirosis?

Answer 56

Leptospira Interrogans

Question 57

What are the L. Interrogans?

Answer 57

Spirochetes

Question 58

How is L. Interrogans transmitted?

Answer 58

Through water contaminated with animal urine usually through a break in the skin

Question 59

Does L. Interrogans cause skin lesions?

Answer 59

Lol, no

Question 60

What can L. Interrogans cause?

Answer 60

FLS, Weil's Dz (jaundice + renal damage), meningitis

Question 61

How is the Dx of interrogans made?

Answer 61

Serology

Question 62

What is the Tx for Leptosporosis?

Answer 62

Penicillin

Question 63

What has reduced the incidence of Leptosporosis in humans?

Answer 63

Vaccination of cattle and household pets

Question 64

What dz does Bartonella henselae cause?

Answer 64

Cat Scratch Dz

Question 65

What is the reservoir of B. Henselae?

Answer 65

Cats (but they're not affected)

Question 66

What patient population is B. Heneselae seen in?

Answer 66

Children

Question 67

What symptoms are seen with Cat Scratch Dz?

Answer 67

Swollen LN's near site of scratch, adults can also have FLS, can lead to severe disseminated Dz involving CNS in ICP's

Question 68

How is the diagnosis of Cat Scratch Dz made?

Answer 68

Presentation and Hx of scratch or bite

Question 69

What is the treatment for Cat Scratch? Tx for long lasting infections?

Answer 69

Most infections clear on their own in two weeks; Erythro for longer infections

Question 70

What other bugs can cause skin lesions or swollen glands?

Answer 70

Anthrax (Eschar); Plague (Bubo in groin or axilla); Tularemia (Ulcer)