Exam #8: Zoonotic & Vector Borne Bacterial Infections II Flashcards Preview

Microbiology > Exam #8: Zoonotic & Vector Borne Bacterial Infections II > Flashcards

Flashcards in Exam #8: Zoonotic & Vector Borne Bacterial Infections II Deck (59):
1

List the characteristics of Borelia.

Long spirochetes
Neither Gram -/+ (Gram negative like)
Mircoaerophilic

2

What diseases do Borrelia cause?

- Lyme Disease
- Relapsing Fever

3

What species of Borrelia cause Lyme disease?

Borrelia burgdorferi

4

What is the leading vector-borne disease in the US?

Lyme Disease

5

What is the major vector of Lyme Disease?

Lxodes spp. (hard tick)

*hard ticks transmit Lyme disease

6

What animals are the reservoirs for Lyme Disease?

Mice
White-tailed deer

7

When is the early stage of Lyme Disease most frequently seen?

Summer

8

What are the symptoms of early stage 1 Lyme Disease?

Localized infection
- Starts as a macule or papule lesion that enlarges to a bull's-eye rash called "erythema migrans"
- Malaise
- Fever
- Headache
- Myalgia
- Lymphadenopathy

*Erythema migrans is pathognomonic for Lyme Disease

9

What is the name of the bull's eye rash?

Erythema migrans

10

What are the symptoms of early stage 2 Lyme Disease?

Disseminated Infection: bacteria disseminate via the bloostream
- Arthralgia
- Myalgia
- Cardiac dysfunction
- Neurologic signs consistent with meningitis and encephalitis

11

What are the symptoms of late stage Lyme Disease?

Arthritis
- One ore more joints with the knee being the joint most commonly infected
- Skin discoloration (grey & ashy)
- Neurologic complaints (numbness, memory loss)

12

How is Lyme Disease diagnosed?

- Symptoms
- physical findings
- hx of exposure

13

How is Lyme Disease streated?

Doxycycline & amoxicillin

14

How is Lyme Disease prevented?

Limit tick exposure

15

What causes epidemic relapsing fever?

Borrelia recurrentis
- Louse-borne (lice)
- this is NOT zoonotic
- tranmission is human to human via the louse

16

What causes endemic relapsing fever?

Borrelia hermsii
- Tick-borne

*This is most common in the US

17

Describe the pathogenesis of relapsing fever.

- Bite from a louse or tick
- Dissemination via multiple organs through bloodstream
- Evasion of the immune system via antigenic variation
- Infection results in febrile & afebrile cycles, hence "relapsing fever"

18

What are the symptoms of relapsing fever?

Chills
Fever
Headache
Muscle ache
Splenomegaly
Hepatomegaly

Symptoms last 3-7 days resolve, and then return after 7 days

19

Outline the antigen/antibody presence in blood smear & symptoms of relapsing fever.

Week 1= Latent period progressing to fever
- Specific antibody produced
- Fever improves
- Antigenic variation

Week 2= progressive bactermia leading to fever again
- Antibody produced
- Fever resides
- Antigenic varation

*Cycle continues

20

How is relapsing fever diagnosed?

- Microscopy- Giemsa stained blood smear
- Culture requires special media
- Serological and molecular techniques can be used to confirm diagnosis

21

How is relapsing fever treated?

Tetracycleine or erythromycin

22

How is relapsing fever prevented?

Limit exposure to arthropod vectors

23

List the characteristics of Rickettsia.

- Very small gram (-) coccobacilli
- Obligate intracellular pathogens-- facilitate their own uptake into endothelial cells, escape from phagosome into the cytoplasm-->lead to focal lysis of filopodia
- Transmitted via arthropod bite

24

Describe the pathogenesis of Rickettsia.

Organisms infect vascular epithelium or small blood vessels

25

What disease is caused by Rickettsia?

Rocky Mountain Spotted Fever (RMSF)

26

What is Rocky Mountain Spotted Fever?

- Most important rickettsial disease in the US
- A severe systemic febrile disease

27

What are the two vectors for RMSF?

Dog tick= NOT in the Rocky Mountains

Wood tick= Rocky Mountian

28

Where do most of the cases of RMSF occur?

NOT in the Rocky Mountains i.e. most commonly transmitted by the Dog Tick, not in the Rockies

29

What are the symptoms of RMSF?

- Initially presents with fever & rash over the extremities
- Rash becomes raised and spreads to the torso (centripital spread i.e. outside-->in vs. centrifugal)
- DIC
- Thrombocytopenia
- Pulmonary edema
- Renal failure
- GI hemorrhage
- Shock

30

How is RMSF diagnosed?

- Epidemiology & clinical signs
- Serology (severe disease may develop before antibody titers are high enough for diagnosis)
- Molecular or immunohistochemical techniques

31

How is RMSF treated?

Doxycycline

32

How is RMSF prevented?

Limiting exposure to ticks

33

List the characteristics of Ehrlichia.

Small gram (-) intracellular pathogens

34

What do Ehrlichia parasatize?

Primarily monocytes & granulocytes

35

What is a morulae? What are morulaes associated with?

Ehrlichia replicate & form colonies within vacuoles known as morulae

36

What causes HME? What is HME? What is the principle vector?

HME= Human monocytic ehrlichiosis
- Ehrlichia chaffeensis

Lone star tick

37

What causes HGE? What is HGE? What is the principle vector?

HGE= Human granulocytic ehrlichiosis
- Anaplasma phagocytophilum

lxodes ticks

38

Describe the pathogenesis of Ehrlichia & Anaplasma.

- Intracellular location protects from humoral immune response
- Bacteria derail phagolysozome maturation
- Activating macrophage with INF-gamma appears to resolve infection

39

What are the symptoms of Ehrlichia & Anapalsma?

- 60 % are asymptomatic
- Remaining 40% are severe enough to require hospitalization

Multi-system zoonosis with malaise, fever, chills, headache, and myalgia
- Petechial rash
- Cough
- Dyspnea
- Resp. distress
- CNS dysfunction

40

How is Ehrlichiosis diagnosed?

- Serological & molecular techniques
- Detection of morulae in blood smear

41

How is Ehrlichiosis treated?

Tetracycline

42

List the characteristics of Coxiella burnetii.

- Small Gram (-) pleomorphic bacterium
- Obligate intracellular pathogen
- Reside and replicate in fully acidified phagolysosomes i.e. they don't interrupt phagolysosome fusion like some of the others that we have covered

43

What is the difference between a small cell variant & large cell variant?

Small cell= have some characteristics of spores
- Resistant to high temperature, osmotic pressure, and UV light
- Can survive in the environment for months
*This is the form of C. burnetii that is infective

Large cell= small cell variants that have grown into large cells; these then divide and the cycle repeats

44

What is the primary reservoir for Coxiella burnetii?

Farm animals
Dogs
Cats

*Note that ticks are an important vector for animals, but NOT man

45

How is Coxiella burnetii transmitted?

Inhalation of small variants

46

What are the symptoms of acute Query fever?

- Generalized disease resembling flu
- Followed by fever, chills, malaise, arthralgias, myalgias, severe headache, and photophobia
- Pneumonia may develop
- Abnormal liver function, CNS dysfunction, and vascular inflammation may be present

*Note that infection during pregnancy may lead to premature birth, abortion, or stillbirth

47

What are the symptoms of chronic Query Fever?

- Mainly endocarditis or hepatitis
- Acute signs of infection absent

48

How is Query fever diagnosed?

Molecular and serological techniques

49

How is Query Fever treated?

Tetracycline (Doxycycline)

50

How is Query Fever prevented?

Inactivated whole cell vaccine

51

List the characteristics of Bartonella.

Small slight curved Gram (-)

52

What two human diseases are caused by Bartonella?

Bartonella quintana-->Trench Fever
Bartonella henselae-->Cat Scratch Fever

53

How is Bartonella transmitted?

Trench fever is transmitted by the human body louse
- It is present in the feces of lice
- As the louse is taking a blood meal, when you scratch & break the skin, you introduce the feces into your wound
*Generally seen in the homeless population

Cat Scratch Fever is transmitted by flea feces that are introduced into the body via a cat scratch or bite

54

What are the symptoms of Trench Fever?

Relapsing fever, headache, and dizziness that lasts 1-3 days & recurs every 4-6 days

55

How is Trench Fever diagnosed?

- Serology
- Isolation of organisms from blood

56

How is Trench Fever treated?

Aminoglycoside (gentamicin) or macrolide (erythromycin)

57

What are the symptoms of Cat Scratch Fever?

- Fever and lymphadenopathy in the region of inoculation
- A papule may develop at the site of inoculation
- Symptoms generally resolve without complication

58

How is Cat Scratch Fever diagnosed?

- Cultivation
- Serology
- Molecular analysis

59

How is Cat Scratch Fever treated?

- Treatment is generally NOT necessary
- Antibiotic use questioned

Decks in Microbiology Class (49):