spirochetes

Question 1

spirochete morphology and structure

Answer 1

• elongated, flexible, motile
• spirally wound flagella anchored at poles
• binary fission
• gram-negative

Question 2

three groups of spirochetes

Answer 2

• treponema
• borrelia
• leptospira

Question 3

diseases caused by treponema

Answer 3

• syphilis
• yaws
• pinta

Question 4

diseases caused by borrelia

Answer 4

• relapsing fever

- Lyme Disease

Question 5

diseases caused by leptospira

Answer 5

leptospirosis

Question 6

how can treponema pallidum be viewed?

Answer 6

• too small for gram stain
• darkfield microscopy
• immunofluorescence
• silver salts
• electron microscopy

Question 7

treponema pallidum storage and culture

Answer 7

• can not be grown in culture
• can be kept alive in rich media under anaerobic condition
• survive in blood 24 hours
• survive in tissue for several days

Question 8

treponema pallidum transmission

Answer 8

• direct contact of genitalia/mucous membranes
• not transmissible in late stages
• mother to fetus (congenital syphilis), still birth, abortion
• rare: transfusion, or contact

Question 9

treponema pallidum pathogenesis

Answer 9

• incubation 2-6 weeks but bacteria present and replicating
• primary lesion - 1-4 weeks after infection on genitalia
• secondary lesion - after dissemination, generalized skin rash 2-20 weeks post primary lesion
• tertiary lesion - late in disease many years after infection in CNS, rubbery, called “gumma”

Question 10

treponema pallidum diagnosis

Answer 10

• pathogenic signs
• history of exposure
• organisms in lesion
• positive tests

Question 11

treponema pallidum tests

Answer 11

• nonspecific (VDRL, flocculation)
• FTA-ABS
• micro hemagglutination test
• ELISA
• TPI

Question 12

syphilis false positives and negatives

Answer 12

• may read positive in presence of mono or malaria
• ## VDRL has more false results than FTA-ABS

Question 13

what test is specifically not used for treponema pallidum?

Answer 13

PCR - no specific primers at diagnostic level

Question 14

antibiotics for treponema pallidum

Answer 14

• very sensitive to penicillin

- tetracycline, erythromycin

Question 15

vaccine for treponema pallidum?

Answer 15

no vaccine

Question 16

Yaws, cause and description

Answer 16

• Treponema pertenue
• non-venereal, only through open sores
• often in children
• patients show positive syphilis test
• no placental transmission
• primary lesion resembles raspberry (yaws)

Question 17

Bejel, cause and description

Answer 17

• Treponema pallidum subspecies endemicum
• similar to yaws
• children in Syria
• treat with penicillin

Question 18

Pinta, cause and description

Answer 18

• Treponema carateum
• central and south america
• flat, non-ulcerating skin lesions of hands, feet, scalp, leaving depigmented areas after healing
• treat with penicillin

Question 19

Lyme disease reservoir and vector

Answer 19

• white footed mouse reservoir

- deer tick vector

Question 20

relapsing fever pathogenesis

Answer 20

• several Borrelia spirochete species

- fever 4-5 days, afebrile 7-10 days, then recurrence and disappearance of fever again. 3-10 relapses total.

Question 21

Lyme Disease caused by:

Answer 21

Borrelia burgdorferi

Question 22

Lyme Disease pathogenesis

Answer 22

stage one: papule with expanding erythema 3-14 days after bite, fever, headache, stiff neck, malaise
stage two: neurologic and cardiac involvement
stage three: migrating arthritis weeks to months after bite

Question 23

Lyme disease diagnosis:

Answer 23

• difficult to isolate organism
• clinical diagnosis mostly
• ELISA test to detect antibodies against B. burgdorferi is available

Question 24

lyme disease complications/late manifestations

Answer 24

• chronic arthritis

Question 25

lyme disease treatment

Answer 25

- tetracycline | - ampicillin for young children

Question 26

unique feature of lyme disease B. burgdorferi:

Answer 26

iron non-requirement

Question 27

Leptospirosis transmission

Answer 27

- usually from animal urine (rats, dogs) | - through skin or mouth

Question 28

leptospirosis pathogenesis

Answer 28

- enters blood - various tissues and organs - kidney, liver, meninges, conjunctiva especially

Question 29

leptospirosis symptoms

Answer 29

- muscular pain - headache - photophobia - fever, chills

Question 30

what is Weil's Disease?

Answer 30

infectious jaundice caused by one specific serovar of Leptospira. Leads to renal failure and hepatic injury.

Question 31

Leptospirosis treatment

Answer 31

penicillin, erythromycin, tetracyclines

Question 32

vaccine for leptospira?

Answer 32

None.