Rickettsiae

Question 1

What is the most important Ricketssial disease?

Answer 1

Typhus

Question 2

What was the real reason of death in the potato famine?

Answer 2

People got typhus

Question 3

Describe the Ricketssial morphology.

Answer 3

Small, short, gram-negative rods

Question 4

What is the best stain for Ricketssia? Why?

Answer 4

Giemsa - since they are intracellular

Question 5

What makes Ricketssia similar to Chlamyidia?

Answer 5

Both are obligate intracellular parasites

Question 6

How do Ricketssia enter our cells?

Answer 6

Stimulate phagocytosis

Question 7

Rickettsiae are capable of making their own _____ but prefer to act as _______ parasites.

Answer 7

ATP

energy

Question 8

What Genera of Ricketssia is named after the person who looked for the magic bullet against syphilis.

Answer 8

Ehrlichia

Dr. Ehrlich - father of chemotherapy

Question 9

How are Ricketssia divided?

Answer 9

Into the spotted fever group and the typhus group

Question 10

How are Ricketssia transmitted?

Answer 10

Lice, ticks, fleas, mites

Question 11

How do Ricketssia get into host cells?

Answer 11

Invade the capillaries at the site of entry and attach to endothelial cells.
Phospholipase A causes local degradation of host cell membrane
Damaged area and microbe are phagocytosed
Reproduce in cytoplasm

Question 12

How does Ricketssia reproduce?

Answer 12

binary fission

Question 13

What are the different ways in which Ricketssia can leave host cells?

Answer 13

Burst out of host cell
transmigrate across membrane
Budding - get envelope for protection

Question 14

With Ricketssia, eventually, all ________ are involved.

Answer 14

organs

Question 15

Typhus is the greek word for what?

Answer 15

stupor

Question 16

Cause of classic epidemic louse-borne typhus

Answer 16

C. prowazeckii

Question 17

Recurrent typhus

Answer 17

Brill-Zinsser disease (caused by R. prowazeckii)

Question 18

When was the last big Tyohus outbreak?

Answer 18

WW2 in Europe

Question 19

What are common features of Typhus?

Answer 19

Fever, headache, myalgias

Question 20

How else may Typhus present (i.e. what signs)?

Answer 20

Meningoencephalitis
myocarditis
thrombocytopenia

Question 21

Typhus may progress to shock, cerebral and pulmonary edema due to ___________ from damaged ______ ________.

Answer 21

extravasation (leakage of fluid out of vessel)

blood vessels

Question 22

What kind of rash will typhus cause? Where will it not be found (usually)?

Answer 22

Maculopapular rash on trunk that spreads to extremities

BUT, not usually on face, palms or soles

Question 23

If we get skin eruptions that also include the palms and soles, this is a very important diagnostic point. What might be causing this?

Answer 23

Rocky mountain spotted fever

Secondary syphilis

Question 24

How does one get Sylvatic typhus?

Answer 24

Via contact with flying squirrels (USA)

Question 25

Untreated louse-borne typhus (R. prowazeckii), if untreated, has a mortality rate of what?

Answer 25

50%

Question 26

What is the flea borne Typhus?

Answer 26

R. typhi

Question 27

Why is the murine typhus (R. typhi) a misnomer?

Answer 27

B/c the worldwide distribution parallels that of rats (not mice)

Question 28

Who had sick English skills?

Answer 28

Hans Zinsser

Question 29

What is the causative agent of Rocky Mountain Spotted Fever?

Answer 29

Ricketssia ricketsii

Question 30

Where is Ricketssia ricketsii (causative agent of Rocky mountain spotted fever) found most commonly?

Answer 30

Southeast united states (Georgia, Florida, Carolina, etc.)

Question 31

In Rocky Mountain Spotted fever, where does the rash first develop?

Answer 31

Ankles, feet, wrists

Question 32

Where may eschar form in Rocky mountain spotted fever?

Answer 32

At tick bite

Question 33

The rash may become petechial and spread to other body parts. What are they?

Answer 33

Palms and soles

Question 34

What cases of RMSF are the most difficult to diagnose?

Answer 34

Cases without rash

Question 35

What is the causative agent of Ricketssial pox?

Answer 35

R. akari

Question 36

If someone says that have gotten chicken pox twice, what is the most likely reason?

Answer 36

Ricketsialpox - cannot tell the difference between it and chicken pox clinically

Question 37

How is R. akari transmitted?

Answer 37

Transmitted from mice or voles via mites

Question 38

What kind of rash is R. akari?

Answer 38

Papulovesicular

Question 39

How is Orientia tsutsugamushi: | Transmitted?

Answer 39

transmitted by chiggers

Question 40

What are chiggers?

Answer 40

Mite larvae

Question 41

Who was the father of chemotherapy?

Answer 41

Paul Ehrlich

Question 42

R. Erlichia is transmitted via what? | What is an exception?

Answer 42

Tick-borne | Exception: N. sennetsu - sashimi infested with infected trematodes

Question 43

What is an extremely common sign of Erhlichiosis?

Answer 43

Leukopenia

Question 44

R. ehrlichia reproduce in _______ producing characteristic inclusions called _________.

Answer 44

vacuoles | morulae

Question 45

Why is it named Q fever?

Answer 45

Q = query - the cause was unknown for many years

Question 46

How is Q fever different from other Ricketssial diseases (4)?

Answer 46

1 - Buds from infected cells 2 - Primary disease is CA pneumonia 3 - Resistant to heat and drying; persists outside host for a long time 4 - Transmitted by inhalation of infective droplets and dust from farm animals, occasionally from raw milk

Question 47

What are the phases of Q fever?

Answer 47

Phase 1 - LPS blocks surface proteins from Ab | Phase 2 - less infectious

Question 48

Acute Q fever infections have what antibody?

Answer 48

Phase 2 Ab only

Question 49

2/3rds of chronic cases of Q fever present how?

Answer 49

Culture-negative endocarditis

Question 50

What is necessary for diagnosis of Ricketssial diseases?

Answer 50

Laboratory testing and serology (mainstay)

Question 51

Although serology is the mainstay of diagnosis of Rickettsia, what must be kept in mind?

Answer 51

Results are not available early so... | be weary of it and treat early