Mycoplasma, Spirochetes, Chlamydia, and Rickettsia II Flashcards

1
Q

Relapsing fever often described as epidemicor endemic

A

Borrelia recurrentis

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2
Q

Organism released only after crushing the lice; not transmitted in saliva, excrement or transovarially

A

Borrelia recurrentis

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3
Q

Transmitted by bites from infected ticks(different than those causing Lyme disease); infected ticks are healthy and transmit transovarially

A

Endemic relapsing fever (Borrelia recurrentis)

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4
Q

Serve as a reservoir for borella recurrentis

A

Rodents and small animals

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5
Q

Occurs in certain arthropod vectors as they transmit disease-causing pathogens from parent arthropod to offspring arthropod

A

Transovarial transmission

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6
Q

Sudden onset of fever with chills, severe headache and malaise lasting 3-6 days and ending abruptly

A

Relapsing fever

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7
Q

The relapse in relapsing fever occurs

A

7-10 days later

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8
Q

The severity of symptoms and duration of illness progressively decrease with each

A

Relapse

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9
Q

Usually associated with a single relapse

A

Louse-borne relapsing fever

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10
Q

Primarily a disease of wild and domestic animals, human infection through direct or indirect contact with animals

A

Leptospira

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11
Q

What is the source of infection with leptospira in descending order?

A

Dogs, livestock, rodents

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12
Q

Chronic renal infection in animals may be asymptomatic leading to continuous shedding of the organism in the urine

A

Leptospira

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13
Q

Human infection usually indirect, from ingestion of contaminated water or food, or swimming or bathing in contaminated water

A

Leptospira

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14
Q

Leptospira are viable in water for

A

Several weeks

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15
Q

Likely very under-reported; may be a prominent zoonosis, especially in tropical regions

A

Leptospira

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16
Q

Both primary and secondary lesions rich in spirochetes and highly infectious

A

Treponema pallidium

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17
Q

Most often transmitted by sexual intercourse, but can be transmitted through the placenta or during birth, by kissing, by transfusion of fresh human blood, other sexual contact or by accidental direct inoculation

A

Treponema pallidum

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18
Q

Can invade virtually any organ in the body and the CNS

A

Treponema pallidum

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19
Q

Can have active lesions on fingers, breasts, lips, oral cavity or genitals

A

People infected with syphilis

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20
Q

Heals spontaneously. 30% of infected are completely cured without treatment

A

Primary stage of syphilus

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21
Q

The secondary stage of syphilis is the disseminated stage where we can see secondary lesions

A

Anywhere on the body

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22
Q

Serologic tests positive, but no clinical manifestations; 30% stay at this stage if untreated, however blood remains infectious

A

Latent stage of syphilis

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23
Q

Slow progressing and we can see inflammatory disease affecting any organ in the body

A

Late (tertiary) stage of syphilis

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24
Q

Symptoms range from subacute meningitis to mental deterioration

A

Neurosyphilis

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25
Q

Cardiovascular syphilis leads to necrosis of the

A

Aorta

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26
Q

Lesions in skin (painless) and bone (deep, gnawing pain)

A

Gummatous syphilis

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27
Q

May result in fetal death and resulting miscarriage, or stillborn at term; signs of congenital syphilis may appear in childhood as developmental abnormalities

A

Congenital syphilis

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28
Q

What are some of the signs of congenital syphilus?

A

Notched teeth, saber shins, and saddle nose

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29
Q

Because live bacteria are present in primary and secondary syphilis–ANY physical contact-either sexual, or nonsexual, can

A

Spread the infection

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30
Q

Can be quickly and directly detected upon examination of exudate from primary, secondary and congenital lesions by dark-field microscopy

A

T. pallidum

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31
Q

Measure either nonspecific nontreponemal or specific antitreponemal antibodies

A

Serological tests for T. pallidum

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32
Q

Rely on the fortuitous observation that Ab’s to a lipoidal antigen present in a wide array of host tissues are specifically generated upon syphilis infection

A

Nontreponemal Tests

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33
Q

These antibodies are referred to as

A

Reagin

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34
Q

Utilize cardiolipin extracted from mammalian tissue (e.g. beef heart) as the Ag

A

Nontreponemal Tests

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35
Q

Then addition of lecithin and cholesterol sensitizes the cardiolipin to react with syphilitic reagin, resulting in

A

Flocculation

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36
Q

What are the two types of tests to measure the presence of reagin?

A

Flocculation tests and Complement fixation

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37
Q

Reagin in serum can fix complement in the presence of

A

Cardiolipin

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38
Q

Unfortunately though, generation of reagin antibodies occur in

A

Other infections

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39
Q

Patients with progressive tertiary syphilis may spontaneously become negative using

A

Nontreponemal tests

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40
Q

Detect T. pallidum antibodies in patient serum

A

Specific treponemal tests

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41
Q

Once treponemal Abs are generated, they remain for

A

A lifetime

42
Q

What percentage of patients with primary syphilis will be true positives?

A

60-85%

43
Q

Which percentage of secondary and tertiary syphilis patients will be truly positive?

A

100%

44
Q

What are two examples of common treponemal Ab tests?

A
  1. ) FTA-ABS

2. ) TPHA

45
Q

Indirect immunofluorescence; rabbit T. pallidumas Ag, test for Ab in serum

A

FTA-ABS (Fluorescent Treponemal Ab)

46
Q

RBCs treated to adsorb T. pallidum on surface, RBCs then clump when mixed with antitreponemalantibodies

A

TPHA (T. pallidum hemagglutination)

47
Q

What are the two major groups of Rickettsia and Orientia?

A
  1. ) Spotted fever group

2. ) Typhus group

48
Q

What are the two components of the spotted fever group?

A

Rickettsia rickettsii and rickettsia akari

49
Q

What are the three components of the typhus group?

A

Rickettsia prowazekii, Rickettsia typhi, and Orientia tsutsugamushi

50
Q

Severity of diseases these organisms cause is variable depending on the organism and host factors

-All are obligate intracellular organisms

A

Erlichia, anaplasma, and Coxiella

51
Q

All organisms except Coxiellaare transmitted to humans by

A

Arthropod vectors such as fleas, lice, mites, and ticks

52
Q

A zoonosisin which sheep, goats and cattle constitute the primary reservoirs that shed the organism in urine, feces, birth products and milk

A

Coxiella Burnetii

53
Q

Targets columnar epithelial cells that line mucous membranes; correlates well with infections it causes (conjunctivitis, cervicitis, pneumonia)

A

Chlamydia

54
Q

Most target endothelial cells that line blood vessels; vascular lesions throughout body produce systemic manifestations and hallmark rash

A

Rickettsia

55
Q

The seasonal and geographical distribution of the diseases caused by these organisms is dependent on the habitat of the

A

Vector

56
Q

Tick behavior also influences seasonality, clinical presentation and age of human population targeted for tick-borne diseases caused by

A

Rickettsia rickettsii, Ehrlichia and Anaplasma

57
Q

In most cases, humans are incidental hosts and do not help propagate the

A

Organism

58
Q

The exception to this rule is

-causes louse-borne typhus

A

Rickettsia prowazekii

59
Q

Common symptoms of infection in both are fever, headacheand rash

A

Rickettsia and orientia

60
Q

Highly adapted for intracellular survival

A

Rickettsia

61
Q

Have undergone genomic reduction by relying on their host to provide many essential amino acids, nucleotides and other nutrients; uses transport system to bring these nutrients into the cell

A

Rickettsia

62
Q

More closely related to mitochondria than other bacteria

A

Rickettsia

63
Q

most virulent of the group, ~5% fatality rate (~25% in the preantibioticera)

A

Rickettsia rickettsii

64
Q

Rickettsia rickettsii causes

A

Rocky mountain spotted fever

65
Q

Early diagnosis is deceptively difficult because hallmark rash appears 2-4 days after onset of illness

A

Rocky mountain fever

66
Q

Rickettsia rickettsii attach to receptors on host vascular endothelial cells via the outer membrane proteins

A

OmpA or OmpB

67
Q

Escape from phagosome into host cytosol & proliferate

A

Rickettsia Rickettsii

68
Q

Proliferation in cytosol leads to cell damage leading to increased vascular permeability

A

Rickettsia Rickettsii

69
Q

Rickettsia rickettsii spread to adjacent cells through hoest cell

A

Actin-mediated propulsion

70
Q

A manifestation of the networks of contiguously infected cells

A

The characteristic petechial rash

71
Q

Dermacentor variabilis, the American dog tick, is the predominant vector in the eastern two thirds of the United States; Dermacentor andersoni, the Rocky Mountain wood tick, is the prevalent vector in the Western states for

A

Rocky Mountain Spotted Fever

72
Q

What is the incubation period for Rocky Mountain Spotted Fever (RMSF)?

A

2-14 days (median of 7 days)

73
Q

Disease begins with fever, severe headache, myalgia; rash (90% of patients, petechialin ~50% of cases)

A

RMSF

74
Q

Occurs 3-5 days after onset of fever, usually begins around wrist and ankles and spreads toward trunk

A

Rash from RMSF

75
Q

Rocky Mountain “spotless” fever (10% of cases) is documented mostly in

A

Older or black patients

76
Q

Transmitted to humans through a mouse mite (small and colorless; bite is painless); however seroprevalence high in NYC dogs so another vector suspected

A

Rickettsialpox

77
Q

Rickettsialpox is caused by

A

Rickettsia akari

78
Q

What are the target cells of Rickettsia akari?

A

Macrophages/monocytes

79
Q

Characterized by a primary papule, which ulcerates and forms the dark eschar (clinical hallmark -present 100% of the time)

-At the site of the tickbite

A

Rickettsialpox

80
Q

Only Rickettsia that is capable of causing devastating epidemics

A

Rickettsia prowazekii

81
Q

Rickettsia prowazekii causes

A

Louse-borne typhus

82
Q

Transmitted by close person-to-person contact by the body louse

A

Louse-borne typhus

83
Q

The body louse is strictly adapted to humans; it lives in clothes and takes a blood meal

A

5 times/day

84
Q

Recently, flying squirrels in the US shown to be stable reservoirs for

A

R. prowazekii

85
Q

Now categorized as an agent for bioterrorism (Category B) because it can be aerosol-transmitted and weaponized

A

R. prowazekii

86
Q

Severe headache, fever, myalgia and rash that spreads from trunk to extremities (opposite RMSF) is characteristic of

A

Louse-borne typhus

87
Q

The louse-borne typhus rash spares the

A

Face, palms, and soles

88
Q

The primary illness from R. prowazekii is louse-borne typhus. The recrudescent form is

A

Brill-Zinsser disease

89
Q

Thought to arise from stress or from a compromised immune system

A

Brill-Zinsser disease

90
Q

Systematic endothelial infection with symptoms similar to RMSF and louse-borne typhis, but usually milder

A

Murine typhus

91
Q

Murine typhus is caused by

A

Rickettsia Typhi

92
Q

Nearly all cases of murine typhus present with

A

Fever

93
Q

Scrub typhus is transmitted transovarally, favoring females. It is caused by

A

Orientia tsutsugamushi

94
Q

Unlike most rickettsia, infection does not occur through endothelial cells

A

Ehrlichia and anaplasma

95
Q

Infects monocytes and macrophages

A

Ehrlichia

96
Q

Infects neutrophils

A

Anaplasma

97
Q

Multipy within cytoplasmic membrane-bound vesicles that look like inclusion bodies but are referred to as morula

A

Ehrlichia and anaplasma

98
Q

Cell walls are thin because they lack peptidoglycan and LPS

A

Ehrlichia and anaplasma

99
Q

Majority of cases in May-August in south-central and southeastern US, i.e. the habitat of the lone star tick, the dog tick, and Ixodes pacificus

A

Human Monocyte Ehrlichiosis (HME)

100
Q

Human Monocyte Ehrlichiosis (HME) is caused by

A

Ehrlichia chaffeensis