Arbo-Bacteria

Question 2

vertebrate hosts for Lyme disease

Answer 2

Rodents

Question 3

vectors for lyme disease

Answer 3

black legged ticks

Question 4

borrelia burgdorferi (the bacterial cause of lyme disease) is a?

Answer 4

spirochete

Question 5

the most common place to develop arthritis secondary to lyme disease is the?

Answer 5

knee (86% in one study)

Question 6

at what time of year is Lyme disease spread?

Answer 6

summer months, peaking in July

Question 7

what are the 3 life stages of a tick and what must occur before development into each subsequent stage?

Answer 7

larvae ? nymph ? adult, must have 1 blood meal at each stage

Question 8

what is the typical feeding cycle of a tick (what host at what stage)?

Answer 8

larvae feed on rodent with b. burgdorferi ? nymph feed on humans or rodents and transmit spirochete ? adults feed on deer, sometimes humans

Question 9

how do black legged ticks acquire borrelia burgdorferi?

Answer 9

they must feed on an infected mouse/rodent (no vertical transmission)

Question 10

how long must ticks feed in order to transmit borrelia?

Answer 10

48 hours, because this is how long it takes for the spirochetes to travel from the tick gut to the tick saliva

Question 11

where in the US is the incidence of Lyme disease greatest?

Answer 11

NE, upper midwest (kind of follows democratic voting haha)

Question 12

how is the global distribution of Lyme disease different from most?

Answer 12

found in temperate regions, rather than tropical like most

Question 13

genome of b. burgdorferi

Answer 13

full of plasmids, membrane proteins constantly change and remodel

Question 14

how does b. burgdorgeri cause disease in host?

Answer 14

extracellular, antibodies cannot clear infection, lipoproteins activate TLR2 and cause inflammation

Question 15

how is b. burg able to survive in so many different hosts?

Answer 15

phase variation, can turn genes on and off

Question 16

how does b. burgdorgeri evade the human immune response?

Answer 16

antigenic variation through DNA recombination of the vls cassette – surface is constantly changing and antibodies cannot keep up

Question 17

most lyme disease patients don’t recall a tick bite because?

Answer 17

the nympho stage when humans are usually infected is very small

Question 18

what type of rash is seen with lyme disease?

Answer 18

erythema migrans (darker on the outside than in the middle)

Question 19

symptoms of stage I LD

Answer 19

local erythema migrans

Question 20

symptoms of stage II LD

Answer 20

arthritis, meningitis, carditis, secondary erythema migrans

Question 21

symptoms of stage III LD

Answer 21

long-term survival of BB; arthritis, encephalopathy

Question 22

diagnosis of Lyme disease

Answer 22

serology is current method, still not ideal (culture has low success, PCR still experimental)

Question 23

treatment of Lyme disease

Answer 23

short term antibiotic therapy

Question 24

RMSF is transmitted by _____.

Answer 24

dog ticks (Dermacentor ticks)

Question 25

STARI is transmitted by _____.

Answer 25

Lone Star Ticks

Question 26

a typical STARI rash

Answer 26

bull’s eye, central clearing, outer ring (no evidence of arthritis)

Question 27

RMSF in the East is transmitted by _____.

Answer 27

American dog ticks

Question 28

RMSF in the West is transmitted by _____.

Answer 28

Rocky Mountain wood ticks

Question 29

Unlike B. burgdorferi, R. rickettsii can transmitted to ticks via?

Answer 29

vertical tranmission

Question 30

In comparison to Lyme disease, RMSF has a _____ grace period.

Answer 30

shorter (10-24hrs), don’t have to travel from the gut lumen (live in salivary glands already)

Question 31

Rickettsia rickettsii

Answer 31

obligate intracellular bacteria that divide in cytoplasm of infected cells, energy parasites

Question 32

how to RR invade neighboring cells?

Answer 32

ACTIN ROCKETS! (escape double membranes once inside)

Question 33

pathophysiology of RMSF

Answer 33

RR targets vascular endothelial cells, damage results in DIC, loss of blood, shock (also chills, fever, HA)

Question 34

without treatment, case fatality of RMSF is?

Answer 34

25%

Question 35

most practical method for diagnosis of RMSF is ______, but the rapid progression of the disease means that it should be diagnosed based on _______.

Answer 35

serodiagnosis (IFA and latex agglutination); clinical findings

Question 36

treat RMSF with?

Answer 36

tetracycline antibiotics

Question 37

where do ehrlichia replicate?

Answer 37

within vacuoles

Question 38

symptoms of HME and HGE include?

Answer 38

fever, malaise, myalgia, HA, rash, rigors, etc. (nonspecific)

Question 39

Ehrlichia chaffeensis causes ______ in ____-nuclear WBCs.

Answer 39

morulla (cytoplasmic inclusions); mononuclear lymphocytes

Question 40

Anaplasma phagocytophilum invades?

Answer 40

neutrophils (PMNs)

Question 41

Ehrlichia chaffeensis is transmitted by ________, the same vector as _______.

Answer 41

Lone Star Ticks; STARI (found in SE where deer are definitive hosts)

Question 42

Anaplasma is transmitted by ________, the same vector as _______.

Answer 42

black legged ticks; Lyme disease

Question 43

we can determine that an infection is active by noting that antibody titers are _____.

Answer 43

rising