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Skin MS: Week 3 > Tick-borne Illnesses > Flashcards

Tick-borne Illnesses Flashcards

1
Q

3 kinds Tick-borne pathogens

A

Bacteria (Borrelia), Euk. parasites (Babesia), Viruses (TB encephalitis virus)-Europe

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2
Q

3 kinds ticks carrying disease in US

A 
Ixodes scapularis (in MN, East Coast, southeast)
Ixodes pacificus (West Coast)
Amblyomma americanum (southeast)
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3
Q

Ixodes scapularis carries 3 diseases

A

Lyme disease, Anaplasmosis, Babesiosis (all growing in incidence and range), specifically in MN (note, w/ CC, expanding into Canada)

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4
Q

Tick life cycle

A

Larva - Hatch from eggs, lack pathogen → BLOOD MEAL → Nymph - taken one blood meal, may have acquired pathogen → Adult - multiple blood meals, may have acquired pathogen

nymph and adult (female) transmit disease

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5
Q

Main reservoir host of Ixodes scapularis

A

White footed mouse

deer only fed on by adult ticks

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6
Q

Onset of illness most frequently when

A

may through september

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7
Q

What to do if find attached tick?

A

Try to estimate duration of tick-attachment (bacterial transmission takes >24 hrs, parasites even longer, viruses shorter time? → NOTE: This number is kind of made up, look for new research)
Remove tick with forceps or gloved fingers
Clean area with disinfectant
No value in submitting tick for analysis
Observe bite site for 30 days (for characteristic rash)
Seek medical assistance for febrile illness

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8
Q

Disease Prevention

A

DEET-repellent on skin, Permethrin on clothing, light colored clothing, socks outside pants, daily inspection of skin and removal of ticks

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9
Q

Where are ticks

A

@ Interface between woodlands/grassy areas - Ticks in grassy areas, hosts in woods

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10
Q

Cause of Lyme Disease

A

Borrelia burgdorferi

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11
Q

Acute stage sometimes presents with characteristic rash, Arthritis-like symptoms in chronic stages

A

Lyme Disease

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12
Q

B. burgdorferi characteristics/virulence factors

A

Fastidious, micro-aerophilic spirochaete ,Grows best at 32C on BSK medium
Flagella - move in corkscrew manner
Longer than they are wide (20-30 micrometers, 0.3 wide)

Surface proteins are host-dependant
OspA in tick, OspC in human
Can disseminate widely in mammal
Remain in midgut of insect until blood meal, then migrate to salivary glands

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13
Q

Various species of BB

A

Various species
B. burgdorferi sensu lato (worldwide)
Bb sensu stricto (USA) → LD
B. garinii, B. afzelii, B. miyamotoi

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14
Q

Cause Human Granulocytic Anaplasmosis (HGA) - transmitted by those I. scapularis and pacificus

A

Anaplasma phagocytophilum

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15
Q

Group of bacteria spread by arthropod vector:
Require living cell for growth – obligate intracellular parasite.
BUT have metabolic enzymes, cell walls, and utilize O2.
extremely small (~0.5 μm in diameter)
Gram negative
Often pleomorphic in shape

A

Rickettsia (barely bacteria)

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16
Q

2 species of rickettsia

A

A. phagocytophilum, Ehrlichia chaffeensis

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17
Q

Features of A. phagocytophilum

A

Replicates in midgut epithelial cells – tick
Some bacteria make it to the salivary glands which are the cells that will be transmitted to initiate mammalian infection
Colonizes neutrophils – mammalian system
In neutrophils, hijacks endocytic pathway to make a vacuole in which to replicate
Morulae = form intracytoplasmic cluster of bacteria

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18
Q

A. phagocytophilum replicated in __________ in ticks

A

midgut epithelial cells

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19
Q

From which area in tick are cells transmitted to initiated mammalian infection (a. phagocytophilum)

A

salivary glands

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20
Q

What do A. P. colonize in mammals?

A

Neutrophils –> make vacuoles in which to replicate

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21
Q

Form intracytoplasmic cluster of bacteria

A

morulae (i.e. A. phagocytophilum)

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22
Q

BB surface proteins

A

OspA in tick
OspC in humans
Need to switch before transmission

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23
Q

Responsible for Rocky Mountain Spotted Fever

A

Rickettsia rickettsii

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24
Q

How are RMSF/RR transmited?

A

different tick, transovarian (through eggs)

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25
Q

What does RR do when it gets in body? (where go and how to replicate)

A

Does not require a specialized human cell to infect
Spread through bloodstream, infect vascular epithelial cell
Replicate in cytosol of cell, not in a vacuole

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26
Q

Cause of Babesiosis/type of pathogen

A

Babesia spp - parasite (i.e. microti)

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27
Q

Babesia = _______ paracite

A

apicomplexan, unicellular

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28
Q

Humans are ______ hosts, sexually reproduce in _________ (Babesia)

A

dead-end hosts,

mice erythrocytes

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29
Q

Virus example of tickborne disease

A

tick-borne encephalitis (TBEV) in Europe, Asia, former USSR

Related Flaviviridae family virus Powassan (POW) in US (rare)

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30
Q

Flaviviruses are (mostly) linear and_______, and are transmitted by the bite ________, primarily mosquitoes and ticks.

A

Flaviviruses are (mostly) linear and single stranded, and are transmitted by the bite arthropods, primarily mosquitoes and ticks.

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31
Q

Lyme Disease Presentation depending on stage

A

Early localized (w/in 30d) - Skin

Early disseminated (days to weeks) - Skin, Cardiac, Neurologic

Late disease (months to years) - Cardiac, neurologic, musculoskeletal

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32
Q

Early Signs and Symptoms

A

Fever, chills, HA, fatigue, muscle/joint aches and swollen lymph nodes
EM rash in 70-80%

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33
Q

Lyme Carditis

A

(~1%) → 2nd or 3rd degree AV block - may require temporary pacing

34
Q

Neurologic Lyme

A

(10-15%) → Bell’s Palsy (CN VII paralysis), Meningitis, Radiculitis

35
Q

Lyme arthritis

A

Knees > other Joints, fewer systemic sxs
1 knee most common (monoarthritis)
Oligoarthritis, shoulder/elbow/TMJ/wrist also occurs
Swelling/effusion significant, pain less than other bacterial or crystalline
Swelling may persist for months after successful tx
Little joint destruction or dysfunction for most patients
In untreated Lyme, 60% of pts may have arthritis which occurs in attacks that decrease over time

36
Q

LD diagnosis

A

Erythema Migrans rash - sufficient for dx if exposure hx present
Lab studies - not helpful in early lyme (too soon)

37
Q

Lyme serology

A

NOT useful in pt with EM, high sensitive/specific in early disseminated and late (arthritis, carditis, neuro manifestations), CSF antibodies useful in CNS

38
Q

Lyme PCR

A

PCR - Good predictive value in synovial fluid for dx of arthritis, not in others

39
Q

2 step testing

A

EIA (highly sensitive) screening
Positive or negative

then
Western Blot (specific)
IgM (2 bands), IgG (5 bands)

strict interpretation

40
Q

LD treatment

A

Doxycycline - tx of choice (10-21 days)
Amoxicillin in children/pregnancy
cephalosporin for late stage

41
Q

Prophylactic tx of LD

A

Nymph/adult I. scapularis tick has been attached for >36 hrs or is engorged
Local rate of tick infectivity is >20%
No contraindication to doxycycline
Treatment is started w/in 72 hrs of removal
Dose is doxycycline 200mg x 1 in adults (not amoxicillin)

42
Q

Should test tick for LD

A

NO

43
Q

PTLDS sxs

A

Joint pain, muscle pain, fatigue, malaise, cognitive problems

44
Q

PTLDS tx

A

Direct tx at sxs, not “infection”

45
Q

Lyme vaccine

A

Vaccine was on the market 1998-2002 (still available for dogs)
Removed for many reasons

46
Q

Human Granulocytic Anaplasmosis (HGA) causative agent

A

Anaplasma phagocytophilum

47
Q

Human Monocytic Ehrlichiosis (HME) causative agent

A

Ehrlichia chaffeensis

48
Q

Anaplasma phagocytophilum and Ehrlichia chaffeensis

A

Obligate intracellular gram negative rods (Rickettsias)

Tropism for WBC –> morulae

49
Q

Anaplasma phagocytophilum and Ehrlichia chaffeensis

Reservoir hosts

A

Deer, white-footed mouse

50
Q

Anaplasma phagocytophilum and Ehrlichia chaffeensis Tick vectors

A

Anaplasmosis - I. scapularis (Deer Tick)
Erlichiosis - Amblyomma americanum (Lone star Tick) - southeast

Direct transmission from deer carcass

51
Q

Anaplasmosis

Erlichiosis - incubation period

A

2-14 days

52
Q

Anaplasmosis/Ehrlichiosis sxs

A

Fever, chills, HA, myalgias

Rash uncommon

53
Q

Anaplasmosis/Ehrlichiosis labs

A

Leukopenia, thrombocytopenia, mild increase in AST/ALT – KEY

54
Q

Anaplasmosis/Ehrlichiosis dx

A

Clinical scenario, with season, exposure history, and clinical presentation is most important

Anaplasmosis –> Peripheral smear shows morulae (Latin for mulberry ~ blackberry) in neutrophils (60-80% of cases)

Ehrlichiosis –> Peripheral smear insensitive (1-20% of cases)

Blood PCR, Serology

55
Q

Babesiosis dominant pathogen + characteristics

A

Babesia microti dominant pathogen in US
Parasite
Most common transfusion-associated infection in US
Same distribution, vector as Lyme

56
Q

Incubation period babesiosis

A

1-6 weeks

57
Q

Clinical syndrome babesiosis

A

Gradual onset of fever, malaise, myalgia, arthralgia
Labs may show elevated bilirubin
Hemolytic anemia

58
Q

Babesiosis dx

A

Peripheral smear
Blood PCR
Serology

59
Q

Babesiosis tx

A

Quinine and clindamycin (difficult to tolerate)

Azithromycin and atovaquone (preferable unless severe)

60
Q

A/E tx

A

Treatment: Doxycycline (Rifampin)

61
Q

Rickettsia rickettsii →

A

Rocky Mountain Spotted Fever

62
Q

Primary tick that transmits R. rickettsii in these states is the _______

A

American dog tick

63
Q

Incubation period RMSF

A

2-14 days (mostly 5-7)

64
Q

RMSF sxs

A

Fever
Rash (occurs 2-5 days after fever) ~ 90% of cases
Small, blanching, pink macules on the ankles, wrists, or forearms that evolve to maculopapules.
Headache, Nausea, Vomiting, Abdominal pain (may mimic appendicitis or other causes of acute abdominal pain), Muscle pain, Lack of appetite, Conjunctival injection

65
Q

RMSF tx

A

Doxycycline for everyone (Even kids) - chloramphenicol alternate but toxic

66
Q

Tularemia pathogen

A

Francisella tularensis (gram negative coccobacillus)

67
Q

F. tularensis hosts

A

Rodents, rabbits classically associated (many mammals)

68
Q

Exposure to F. tularensis

A 
Most commonly tick, biting flies
Direct inoculation (handing dead animal)
69
Q

Tularemia incubation period

A

3-5 days

70
Q

Tularemia presentation

A

Abrupt fever, chills, headache, myalgia, sore throat
Bite site commonly forms nonhealing ulceration/eschar
Ulcero-glandular most common (60-70%)
Pneumonic (~20%)

71
Q

Tularemia dx

A

Labs nonspecific
Cultures often negative (but notify lab of suspicion)
Serology usually confirms (at 2 weeks)

72
Q

Tularemia Tx

A

Aminoglycosides
Doxycycline
Fluoroquinolones

73
Q

Virus causing meningoencephalitis

New England and Great Lakes region

A

Powassan

74
Q

Caused by Colorado Tick Fever Virus
Rocky Mountain distribution
Usually mild, self-limited illness

A

Colorad Tick Fever

75
Q

Borrelia hermsii or turicatae
Western US
Spirochetes detected in peripheral smears or CSF
Treated with doxycycline, tetracycline, penicillin, or ceftriaxone

A

Relapsing Tick Fever

76
Q

Tick to worry about in MN

A

Ixodes scapularis

77
Q

Rickettsia are Gram ____

A

negative

78
Q

EM rash (Lyme disease)

A

Begins at site of tick bite after a delay (average 7 days)
Expands gradually over a period of days reaching up to 12 inches or more (30cm)
May feel warm to touch but is rarely itchy or painful
Sometimes clears as enlarges → Bulls-eye
May appear on any area of the body
Multiple rashes = disseminated1t

79
Q

tx Anaplasmosis/erlichiosis

A

doxycycline (rifampin)

80
Q

Lyme, _______ and ______ have same distribution vector

A

Anaplasma - Babesia microti

ixodes scapularis

Skin MS: Week 3 (14 decks)

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