Vector-borne bacterial infections Flashcards Preview

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Flashcards in Vector-borne bacterial infections Deck (151):
1

bacilli

disease causing bacteria

2

what kind of bacilli is rickettsia

gram-negative

3

what makes rickettsia different from other gram negative rods

1. peptidoglycan layer is minimal
2. LPS has weak endotoxin activity

4

what can you not use for treatment in Rickesttsi? and why?

Beta-lactams because LPD has weak endotoxin activity

5

obligate intracellular

cannot produce outside of host cell

6

where does Rickettsia replicate

in cytoplasm of cell

7

what stain is used to see Rickettsia

Giemsa
Gimenez

8

what is the common name for Rickettsia rickettsii

Rocky Mountain Spotted Fever (RMSF)

9

what is the pathogenic factor in Rickettsia rickettsii? how does it work

outer membrane protein A (Omp A)
- adherence to endothelial cells

10

Rickettsia rickettsii replicates where? this results in what

cytoplasm and nucleus
-vasculitis

11

how does Rickettsia rickettsii bypass the immune system

intracellular growth protects the bacteria from immune clearance

12

what is the most common Rickettsia causing human disease in USA

Rickettsia rickettsii

13

90% of infections occur during what time of year

April - September

14

what is the vector for Rickettsia Rickettsii? what family do they belong to

Ticks
Ixodeae family

15

name the 2 forms of ticks that cause Rickettsia Rickettsii

Dermacentor andersoni (wood tick)
Dermacentor variablilis (dog tick)

16

where is Dermacentor andersoni found

rocky mountain states

17

where is dermacentor variablilis found

Southeast United states

18

what states had the highest incidence rates for Rocky mountain spotted fever

Arkansas
Delaware
Missouri
North Carolina
Oklahoma
Tennessee

19

what is the reservoir for rickettsia rickettsii

ticks via transovarian transmission

20

what is the process of a tick biting a human

- bit is painless and goes unnoticed
- after 6-10 hours ....????

21

how long does rocky mountain spotted fever incubate

2-14 days

22

what are clinical symptoms for rocky mountain spotted fever

fever
chills
headaches
myalgias
abdominal pain
vomiting
hepatitis
respiratory failure
encephalitis
renal failure
hypotension
myocarditis

23

when does the pathogenic rash appear for rocky mountain spotted fever

after 3-5 days

24

where does the pathogenic rash appear for rocky mountain spotted fever? do all victims get this rash

centripetal
palms and soles
no

25

what does centripetal rash mean

spreads from periphery to center

26

what happens in 20% of untreated cases for RMSF

fatal, clinical suspicion is key

27

what will the laboratory findings be for RMSF

Thrombocytopenia
coagulopathy
anemia
normal WBC count
hyponatremia
Transminitis

28

Transaminitis what does that mean

Increased ALT/AST levels
could indicate liver damage

29

for RMSF when is diagnosis idealistic

before the onset of rash is clinical and epidemiological

30

RMSF, the organism in acute phase is detected how in the lab

1. PCR
2. Immunohistochemical methods in skin biopsy
3. serology but confirmation needed

31

according to the CDC, when is RMSF notified to them

fever plus any one of the following
rash
eschar
headache
myalgia
anemia
thrombocytopenia
hepatic transaminase elevation

32

how do you confirm RMSF in the lab

1. fourfold change in IgG specific titer reactive with R. rickettsii by indirect immunofluoresense assay (IFA) b/w paired serum specimens ( one speciemen taken in 1st week, second 2-4 weeks later )
2. detect R. rickettsii DNA in a clinical specimen via amplification of a specific target by PCR asay
3. demonstrate rickettsial antigen in biopsy or autopsy speciment by IHC
4. Isolation of R. Rickettsii from clinical specimen in cell culture

33

for laboratory confirmation of RSMF why is IgM not used

lacks specificity and are usually false +

34

common name for Rickesstia akari

Rickettsailpox

35

what is the world distribution for Rickettsia Akari

cosmopolitan

36

how is Rickettsia akari transmitted

mites

37

what is the reservoir for Rickettsia akari

rodents ( common house mouse)

38

how does R. akari present

biphasic

39

what happens in the first phase for R. akari

1 week after bite: papule to ulcer to eschar at site of bite

40

what happens after the first phase of Rickettsialpox

incubates for 7-24 days
systemic spread

41

what happens in 2nd phage of R. akari

high fever
severe headache
photophobia
papulovesicular rash,
pox-like progression ( vesicles crust over)

42

when does R. Akari 2nd phase heal

within 2-3 weeks

43

for clinical symptoms with R. akari and R. Rickittsii which one has a milder course

R. akari

44

Anthrax

bacterial disease of sheep and cattle, typically affecting the skin and lungs.
- transmitted to humans, causing severe skin ulceration or a form of pneumonia

45

what is the difference in skin rashes with Anthrax and Rickettsialpox

anthrax patients only have eschar
Rickettsialpox: papule --> ulcer --> eschar

46

If Rickettsialpox is on the differential diagnosis list what other thing should be on the list

Anthrax

47

R. Prowazekii has what reservoir

humans

48

how is R. prowazekii transmitted

during blood meal
- louse defecates highly infective feces
- introduced into by body by scratching/hand contamination/ injured skin or mucous membrane

49

how long can lice feces remain infectious in R. prowazekii

100 days

50

how are louse transfered from human to human in R. prowazekii

sharing clothes

51

what are 2 syndromes for R. prowazekii

acute, potentially severe vasculitis
- Brill-Zinsser disease

52

when does acute, potentially severe vasculitis occur in R. prowazekii? what other symptoms present

7-14 days after contact with infected lice
fever, centrifugal maculopapular rash, CNS symptoms

53

what is Brill-Zinsser disease

recrudescent from 10-50 years after primary infection
- milder form, rash, flu-like symptoms, seen in elderly patients WWII refugees

54

how is R. prowazekii tested in the laboratory

serology (MIF) test

55

when is R. Prowazekii prevelent in the world

during disaster, war, famine
rare in US

56

R. prowazekii is transmitted how in the US

usually rare in US
- "flying squirrels"
- squirrels have fleas, fleas bite humans

57

R. Parkeri common names

American Boutonneuse fever
-Tidewater spotted fever

58

where does R. Parkeri usually occur

souther United States

59

what is the vector for R. Parkeri

Amblyomma maculatum ( Gulf Coast Tick)

60

clinical symptoms for R. Parkeri

fever, headache, myalgias
eschars and rash on PE

61

what is the mortalilty rate for R. parkeri

low

62

what lab tests would be used R. Parkeri

serology
PCR
culture from skin biopsy

63

what is the treatment for R. Parkeri

Doxycycline

64

R. Typhi have what reservoir

rodants

65

what is the main vector for R. Typhi

Xenopsylla cheopis ( rat flea) also cat flea ( esp in USA)

66

where is R. Typhi usually found

worldwide, more in warm, humid areas

67

how are humans infected with R. Typhi

inoculation of infective flea feces in bite wounds

68

what is the endemic (murine ) typhus

R. typhi

69

what is the epidemic (louse-borne) typhus

R. prowazekii

70

what are some clinical manifestations of R. Typhi

fever, headache, chills, myalgias
rash ( variable)
mild symtpoms

71

what labs should be runned for R. typhi

serology by IFA

72

what is the common name for Orientia tsutsugamushi

scrub typhus

73

what is the reservoir for Orientia tsutsugamushi

larval mites ( chiggers), via transovarian

74

what is the vector for Orientia tsusugamushi

mites, feed only once in a lifetime

75

where is Orientia tsutsugmamushi found in the world

Asia Pacific rim

76

clinical symptoms of Orentia Tsutsugamushi

severe headache, fever, myalgias
maculopapular rash, spreads CENTRIFUGALLY
CNS complications
heart failure

77

what lab tests check for Orentia Tsutsugamushi

Serology (IFA)

78

what is the drug of choice to treat Rickettsial and Orientia infections

Doxycylcine

79

what are alternative drugs to treat Rickettsial and Orientia infections

Chloramphenical or Fluoroquinolone

80

when should treatment be administered if you think you have Rickettsial or Orientia infections

Immediately , don't wait for confirmatory serology

81

for RMSF what are the rules for giving Doxycline

Normally: don't > 8yrs b/c dental staining/enamal hypoplasia
RMSF: drug of choice regardless of age of patient

82

how should a tick be removed from the skin

don't twist or jerk the tick when pulling with twizzers

83

what are the 5 don'ts for Rickettsial disease

-don't wait for petechial rash to develop
-don't exclude diagnosis because no history of tick bite
- don't exclude diagnosis solely for geographic or seasonal reasons
- don't withhold therapy if there is any suspicion
- don't be afraid to use Doxycyline at any age

84

what type of bacteria are Ehrlichia and Anaplasma

obligate intracellulular

85

Ehrlichia and anaplasma don't have what in the cell memebrane? Therefore what treatment will not work for them

no peptidoglycan or LPS
beta-lactams dont work

86

Ehrlichia and Anaplasma grow on what type of cell

Hematopoietic cells

87

where do Ehrlichia and Anaplasma replicate

phagosomes of host cells

88

what is morula

microcolony of Ehrlichiae within a vacuole

89

Another name for Ehrlichia chaffeensis

human monocytic ehrlichiosis HME

90

what is another name for anaplasma phagocyophilum

human granulocytic anaplasmosis HGA

91

what is the reservoir for Ehrlichia chaffeensis

deer and dogs

92

what is the vector for Ehrlichia chaffeensis

ticks
Amblyomma americanum

93

where is Ehrlichia chaffeensis usually found

southeast
south central and midwest states

94

what and when do clinical symptoms occur for Ehrlichia chaffeenis

1-3 weeks after bite: flue-like symptoms
late onset ( 1 week after) rash (spares hands and feet)

95

what lab work is done for Ehrlichia chaffeensis

serology by IFA
PCR in blood
- peripheral blood (Giemsa) to see morulae in monocytes is insensitive

96

what is the reservoir for Anaplasma phagocyphilum

Deer, sheep, rodents

97

what vector does Anaplasma phagocyphilum use

hard-shelled ticks
Lxodes scapularis pacificus

98

where does Anaplasma phagocyphilum predominantly occur

Northeast/north-central states and Norther California

99

what are the clinical symptoms for Anaplasma Phagocyphilum

1-3 weeks after bite: flue-like symptoms
late onset ( 1 week after) rash (spares hands and feet)

100

what labs are done for Anaplasma Phagocyphilum

-serology by IFA (paired specimens to see increase IgG_
-blood PCR
- peripheral blood ( Giesma) to see morulae in granulocytes is insenstive

101

what are laboratory findings for Anaplasma and Ehrlichia

leukopenia
lymphopenia
thrombocytopenia
elevated liver enzymes

102

what is the drug choice for Ehrlichia and Anaplasma

DOXYCLYCINE REGARDLESS OF AGE

103

what happens if the patient fails to respond to Doxycycline within 3 days

there is an infection with other organism

104

Borrelia recurrentis

epidemic relapsing fever

105

Borrelia spp

endemic relapsing fever

106

Borrelia burgdorferi

lyme disease

107

what type of bacteria is Borrelia

weakly staining, gram neg. spirochetes

108

what makes Borrelia a different bacteria from the rest of them

motile (flagella)
difficult to cultivate

109

what is the leading vector for Borrelia burgdorferi

borne disease in USA

110

what 3 main areas are Borrelia burgdorferi found

Northeast, Minnesotta, and Wisconsin

111

what are other vectors for borrelia burgdorferi

lxodes scapularis
pacificus

112

what is the reservoir for borrelia burgdorferi

white-footed mouse (peromyscus leucopus) and white-tailed deer

113

how is borrelia transmitted

in tick's saliva during prolonged period

114

what time of the year does Lyme disease occur

June and July

115

what is the incubation period for Lyme disease

up to 1 month from tick bite

116

what are the 3 stages of Lyme disease

early localized
early disseminated
late disease

117

what happens in early localized

distinctive rash: erythema migrans (bull's eye)

118

what happens in early disseminated

multiple EM, facial nerve palsy, meningitis

119

what happens in late disease

arthritis (knees) carditis

120

what are symptoms of Lyme disease

fatigue, joint pain, cognitive problems

121

for early stage Lyme disease how is diganosis made and why

clinically b/c Ig are not detectable within the 1st 4weeks of infection

122

what laboratory items would you use for Lyme disease

EIA or FIA
confirmatory Western Blot

123

what is used to treat Lyme disease

Amoxicillin or cefuroxime for children equal to 8 years

124

what is used to treat the CNS, carditis or recurrent arthritis in lyme disease

Ceftriaxone

125

what does STARI stand for

Southern Tick-associated rash illness

126

what are clinical symptoms for STARI

rash typical of erythema migrans and mild flu-like symptoms in NON-LYME ENDEMIC AREAS

127

STARI is associated with a bite by what

Lone Start tick ( A. americanum)

128

Preliminary studies show the cause of STARI is postulated to be a

spirochete: B. lonestari

129

where does STARI occur

Missouri
Maryland
Georgia
South Carolina
North Carolina

130

what may serve as a reservoir for STARI

white-tailed deer

131

name 4 reasons why STARI is different from lyme

onset of lesion was shorter
- less likely to have multiple skin lesions, smaller sized lesions
- rapid recovery
- not linked to arthritis, neurologic disease, or chronic symptoms

132

what medicine is used to treat STARI

Doxycycline
Amoxicillin

133

under what circumstance does B. recurrentis occur

natural disasters
unsanitary conditions

134

what is reservoir for Borrelia spp.

rodents, small mammals

135

how do ticks transmit Borrelia spp.

feed nocturnally and contaminate the wound with saliva and feces that are infectious

136

what are clinical syndromes for relapsing fever

fever, chills, headaches, hepatosplenomegaly

137

what is the timeline for relapsing fever clinical symtpoms

incubation 1 week
afebrile period of 1 week
return symptoms
relapse

138

what is the mortality rate for relapsing fever

high 40%

139

how does one lab diagnose relapsing fever

Giemsa on peripheral blood during febrile episode

140

what is the treatment of relapsing fever

Doxycycline
Penicillin and Erythromycin for pregnant and children under 8 years of age

141

what is Babesia

protozoa

142

Babesia shares the same vector and reservior as what other disease

B. burgdorferi

143

what is the vector and reservoir for Babesia

v: lxodes ticks
r: white footed mouse

144

what is the most common species for Babesia

babesia microti

145

Babesia is what kind of parasite and what does it mimic

INTRA-ERYTHROCYTIC PARASITE
MALARIA

146

what is the life cycle of Babesia

blood meal, introduces sporozoites into human host
- sporozoites enter erythrocytes, asexual replication
- replication causes the disease

147

what are clinical manifestation for Bebsia

hemolytic anemia
influenza like symptoms ( fever, chills, body aches)
Splenomegaly
hepatomegaly
jaundice

148

what are risk factors for Babesia

advanced age, immunocompromised person

149

how is Babesia lab diagnosed

- detected by microscope examination of blood smear (maltese cross)
- double check, b/c hard to distinguish from plasmodium
- PCR detects low levels of parasites

150

why is serology not helpful for Babesia

cannot distinguish between acute versus old infection

151

what is the treatment for babesiosis

combination therapy
mild disease: Atovaquone PLUS azithromycin
severe disease: Clindamycin PLUS quinine