Spirochetes Flashcards Preview

Term 4: Infectious Diseases > Spirochetes > Flashcards

Flashcards in Spirochetes Deck (47):
1

What are the three genera of spirochetes?

-Treponema -Borrelia -Leptospira

2

What organism causes syphilis?

-Treponema pallidum

3

Why can't we see Treponema pallidum on light microscopy? What kind of microscopy is needed to see them?

-they are too narrow -Need darkfield microscopy or EM

4

What is the outermost amorphous layer of Treponema pallidum?

-Glycosaminoglycans

5

What diagnostic tests do we use to detect Treponema pallidum?

Non-treponemal antibody tests: -VDRL (venereal disease research lab of CDC) -RPR (Rapid Plasma Reagin) Treponemal antibody tests: -MHA-TP (MIcrohemagglutination antibody to T. pallidum) -EIA (Enzyme immunoassay)

6

Where does Treponema pallidum get phosphatidylcholine?

-can't make its own -takes it from mammalian host =cardiolipin

7

What tests detect cardolipin in Treponema pallidum?

=non-treponemal antibody tests -VDRL test (venereal disease research laboratory) -RPR (rapid plasma reagin test)

8

What is the epidemiology of Treponema pallidum?

-Natural spread only among humans -Sexual transmission

9

What disease does Treponema pallidum cause?

Syphilis

10

What is weird about the flagella of spirochetes?

They are located underneath the outer membrane

11

What is the first sign of syphilis?

Primary syphilis = lesion called chancre -incubation of 7-21 days before papule appears

12

Why is primary syphilis harder to detect in women and homosexual men?

-chancre often in vaginal canal or rectum -syphilis usually diagnosed in second stage

13

What happens to the primary syphilis chancre without treatment?

-Disappears in 3-4 weeks -reflects development of some immunity

14

What is secondary syphilis?

-organisms have disseminated widely throughout body -Lesions appear all over skin, truck>extremitis and **involves palms of the hands and soles of the feet" -partial immunity prevents these lesions from turning into a chancre

15

What is seen in the CSF of patients with secondary syphilis?

-Treponemes

16

What kind of patient will develop early neurological symptoms of syphilis?

AIDS patient

17

What is latent syphilis?

-organism is in body, but not causing any signs of disease -Occurs in absence of treatment of secondary syphilis

18

What are the three things that can happen once syphilis becomes latent?

1/3 eradicate disease 1/3 remain with latent disease; keep reactive RPR 1/3 develop tertiary syphilis

19

What are the three types of tertiary syphilis?

-Benign -Cardiovascular -Neurologic

20

What is benign tertiary syphilis?

-Gummas: large, immunologically mediated, granulomatous lesions of skin, liver testis, hard palate ***RARE

21

What is cardiovascular tertiary syphilis?

-Aneurysm of ascending aorta due to invasion of vasa vasorum *RARE

22

What is neurologic tertiary syphilis?

Wide variety of sx's -tabes dorsalis -strokes -dementia -paresis *CSF is usually abnormal

23

What is the most reliable diagnosis of primary syphilis?

-detection of treponemes in the canchre by darkfield exam *difficult in secondary lesions

24

What is the treatment for syphilis?

-Long acting penicillin b/c of slow dividing time

25

What is the Jarisch-Herxheimer reaction?

-Treatment of syphilis with penicillin is followed in 4 hours by a fever that may be high and the worsening of lesions

26

What organism causes Lyme disease?

-Borrelia burgdorferi

27

What is the natural reservoir and vector of Borrelia burgdorferi?

Reservoir: White-footed mouse Vector: hard tick (Ixodes)

28

What are the tree stages of Lyme disease?

1) Localized infection 2) disseminated infection 3) Persistent destructive arthritis & cardiac disease

29

What is stage 1 of Lyme disease?

-localized infection -nonspecific generalized symptoms -Erythema migrans

30

What is stage 2 of lyme disease?

-disseminated infection (multiple smaller erythema migrans) -arthritis (large joints), carditis (heart block), neurologic disease (Bell's Palsy) "outbreak" of acute arthritis

31

What is stage 3 of lyme disease?

-Persistent destructive arthritis -cardiac disease

32

What is the cause of leptospirosis?

-Leptospira

33

Which species of Leptospira infects humans?

-interrogans

34

What is the epidemiology of Leptospira?

-Warm climates -rare in USA -infects mammals (rodents, dogs) -US soldiers in Panama *work in or around bayous, contact with sewage or farm animals, presence of rats on property

35

What is the clinical presentation of leptospirosis?

-Non-specific febrile illness -muscle aches -fatal jaundice -renal failure -hemorrhage

36

What is Weil's disease?

-combined renal and liver failure seen in leptospirosis

37

What is Tabes Dorsalis?

-seen in tertiary syphilis -damage to posterior columns and dorsal roots of spinal cord -disrupts sensory perception

38

What is general paresis of tertiary neurologic syphilis?

-progressive disease of the nerve cells in the brain leading to mental deterioration and psychiatric symptoms

39

What disease is caused by Borrelia recurrentis?

-Relapsing fever

40

"Tick/louse bites on campers sleeping in cabins in western U.S."

Borrelia recurrentis or Borrelia hermsii= relapsing fever

41

What is the reservoir and vector of Borrelia recurrentis?

Reservoir = human Vector = louse

42

What is the reservoir and vector of Borrelia hermsii?

Reservoir = rodents and small mammals Vector = tick (humans infected incidentally)

43

What is the clinical presentation of relapsing fever caused by B. recurrentis and B. hermsii?

-Fever, headache, muscle pains (nonspecific) -persists for 4-10 days, then controlled by humoral response -recurrence of symptoms keeps occuring, milder each time

44

Why is relapsing fever caused by B. recurrentis and B. hermsii able to relapse?

-organism changes its outer membrane proteins, escaping humoral immunity repeatedly

45

What kind of heart block can be caused by Borrelia burgorferi?

Atrioventricular heart block

46

What is the easiest way to prevent Lyme disease?

-if a tick bites you, take it off within 18-24 hours so it can't puke on you

47

How are humans typically infected with Leptospira interrogans?

-swallowing water contaminated with animal urine -more common in tropical regions