Borrelia

Question 1

The genus Borrelia includes species causing:

_______(e.g., Borrelia recurrentis, Borrelia duttonii) and
_______(e.g., Borrelia burgdorferi).

Answer 1

relapsing fever

Lyme disease

Question 2

• Helical rods, 8-30 um long and 0.2-0.5 um in diameter

• Antigenic (flagellum, binding/outer surface proteins, etc.) and genetic differences are used to differentiate species

Answer 2

Borrelia

Question 3

Borrelia recurrentis
Vector:

Answer 3

Pediculus humanus

Question 4

Borrelia recurrentis
Vector: Pediculus humanus

MORPHOLOGY/STAINING
CHARACTERISTICS:
• Wet preparations of peripheral blood
• Mixed with equal parts of sterile, nonbacteriostatic saline under dark- or bright-field illumination, in which the spirochetes move rapidly, often pushing the red blood cells around.
• Staining thick and thin films with_______(2) stains using procedures similar to those used to detect malaria.

Answer 4

Wright’s or Giemsa’s

Question 5

Borrelia

Cultivation: Grown in_____ medium in clinical labs.

Answer 5

Kelly

Question 6

Virulence Factors
• _______: Caused by antigenic variation, where Borrelia species alter surface antigens to evade the immune response, leading to recurring febrile episodes.

• _______: Borrelia burgdorferi binds plasminogen and factor H to evade complement and modulate immune responses, contributing to immune suppression.

Answer 6

Relapsing Fever

Lyme Disease

Question 7

• Symptoms:
• Initial Phase: Sudden onset of fever, chills, headache, muscle aches, and weakness. The fever lasts 3-7 days, ending with an immune response.

• Relapse Phase: The fever recurs after a few days or weeks with similar but milder symptoms.

Answer 7

Relapsing fever

Question 8

Transmission:
• Tick-borne: Transmitted by soft ticks (______).

• Louse-borne: Transmitted by the body louse (______), where infection occurs when lice are crushed into the skin.

Answer 8

Ornithodoros

Pediculus humanus

Question 9

Lyme Disease
• Stages:

•	Erythema migrans (EM), a red, expanding skin lesion at the tick bite site.
•	Constitutional symptoms: Fatigue, headache, fever.

Answer 9

Stage 1 (Localized)

Question 10

Lyme Disease
• Stages:

•	skin lesions, migratory joint pain, and neurological symptoms.

Answer 10

Stage 2 (Disseminated)

Question 11

Lyme Disease
• Stages:

•	Chronic arthritis, neurologic issues (e.g., Bell’s palsy), and musculoskeletal problems.

Answer 11

Stage 3 (Persistent Infection)

Question 12

Relapsing Fever:
• Tick-borne: Found globally but varies by species and region.

• Louse-borne: Associated with poor hygiene and overcrowding, common in areas with epidemic outbreaks.

Question 13

Lyme Disease:
• Transmission: From infected_____, with most cases occurring during outdoor activities in summer months.

• Geography: Found in North America, Europe, and Asia.

• Prevention: Wear protective clothing, use tick repellents, and remove ticks promptly

Answer 13

Ixodes ticks

Question 14

RELAPSING FEVER
• Fever, rigors, headaches, myalgia, arthralgia, photophobia, cough;
skin rash may occur

•Fatal cases: involve CNS, spleen, liver, other organs, hemorrhagic lesions (kidneys and GIT)

• Ultimate recovery: after______ relapses

• Clearance:_____

Answer 14

3-10

antibody-mediated killing of spirochetes

Question 15

• tickborne (Ornithodoros), zoonotic

Answer 15

B. duttoni
B. hermsii
B. parkeri
B. turicatae
B. miyamotoi

Question 16

_______: Epidemic relapsing fever

• Definitive: Direct observation from blood specimens of febrile
patients (spirochaetemia)

• Darkfield (wet prep), move rapidly RBCs
• Thick & thin smear, Wright or
Giemsa stains, or acridine orange

• Serology not reliable;

ANTIGENIC SHIFTS

Answer 16

Borrelia recurrentis

Question 17

Borrelia burgdorferi
Vector:

Answer 17

Ixodes tick

Question 18

Borrelia burgdorferi

MORPHOLOGY/STAINING CHARACTERISTICS:
1. Tissue sections stained with:_____
2. Modified Kelly’s medium colonies stained with:______
3. Modified Kelly’s medium (BSK II, BSK-H, or Preac-Mursic)

Incubated at 30°C to 34°C for up to 12 weeks under microaerophilic

Answer 18

Warthin-Starry silver stain
Acridine orange

Question 19

• sole cause of Lyme disease in the USA where Lyme arthritis is a common
  complication of infection.

Answer 19

B. burgdorferi sensu stricto

Question 20

• responsible for the Lyme disease in Europe and are associated with chronic skin and neurologic manifestations, respectively.

Answer 20

B. afzeli and B. garinii

Question 21

B. afzeli and B. garinii vectors

Answer 21

Ixodes dammini
l. pacificus
I. ricinus

Question 22

Borrelia may be grown on liquid medium:_______, seldom used

Answer 22

Barbour-Stoenner-Kelly (BSK II) medium