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Veterinary Bacteriology & Mycology > Leptospira > Flashcards

Leptospira Flashcards

1
Q

What is the structure of Leptospira

A
  • long, spiral, Gram-negative spirochete that usually have hooks at one or both ends
  • winds around an axial filament (2 flagella) embedded between an outer envelope and cytoplasm
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2
Q

What respiration and fermentation does Leptospira undergo?

A

strict aerobe

uses only long-chain fatty acids as their carbon source

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3
Q

What 2 things are required to culture Leptospira? What is it extremely sensitive to?

A
  1. supplementation with 5-10% serum or albumin + B1, B12, and purines, like 5-flurocuracil
  2. grows best at 30 degrees C

heat, light, disinfectants

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4
Q

Leptospira, darkfield microscopy:

A
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5
Q

What are the 2 classifications of Leptospira based on virulence and antigenic differences?

A
  1. L. biflexa = non-pathogenic
  2. L. interrogans = pathogenic
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6
Q

What serovars of L. interrogans are present in the US and Canada?

A

(pathogenic)
L. pomona, L. hardjo, L. canicola, L. icterohemorrgaiae, L. grippotyphosa, L. bratislava

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7
Q

How is Leptospira classified based on genetics?

A

molecular studies have separated into genomospecies
- L. interrogans has 14 genomospecies
- L. biflexa has 6 genomospecies

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8
Q

What is the natural reservoir of Leptospira?

A

lumen of proximal convoluted tubules of the kidney
- may live in tubules for weeks to years, especially in rodents and excreted in urine

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9
Q

Where is Leptospira able to survive for extended periods of time after excretion in urine? In what 4 conditions can it not survive?

A

freshwater, soil, mud

  1. saltwate
  2. low pH
  3. low humidity
  4. low temperature
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10
Q

What are the 7 common serovars of Leptospira causing animal disease?

A
  1. L. kennewicki - horses
  2. L. bratislava - horses
  3. L. pomona - pigs, cattle, horses, skunks
  4. L. canicola - dogs, pigs
  5. L. icterohaemorrhagiae - dogs, cattle, pigs, rats
  6. L. hardjo - cattle
  7. L. grippotyphosa - dogs, wildlife (raccoons, skunks)
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11
Q

The virulence factors of Leptospira are not well-understood. What 6 substances/actions have been found in mutants?

A
  1. LPS - 10x less toxic than E. coli
  2. catalase
  3. axial filament - motility
  4. sphingomyelinase - hemolysin
  5. cytotoxins - protein, glycoprotein
  6. ability to invade cells
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12
Q

Most vertebrates are susceptible to Leptospira infection. What are 7 common diseases caused by infection?

A
  1. premature birth
  2. abortion
  3. infertility
  4. jaundice
  5. agalactia
  6. hemoglobinuria
  7. fever, inappetence, malaise
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13
Q

How does disease presentation with Leptospira compare in dogs and cats?

A

DOGS: acute hemorrhagic or chronic icteric and uremic syndromes

CATS: rarely gets clinical disease

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14
Q

What species of Leptospira most commonly causes acute/subacute infection in cattle? What production, clinical, and laboratory changes are evident?

A

L. pomona

  • PRODUCTION: abnormal milk, agalactia
  • CLINICAL: rash, intense muscle pain, GI signs, photophobia, encephalitis, acute nephritis, hemoglobinuria
  • LAB: hemoglobinuria, increased BUN
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15
Q

What species of Leptospira causes chronic disease in cattle and swine? What 4 things does this cause? What causes this?

A

L. pomona

  1. nephritis
  2. uveitis
  3. encephalitis
  4. infertility

antigen-antibody complexes

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16
Q

What species of Leptospira commonly causes disease in calves? What 3 things does this cause?

A

L. hardjo

  1. abortion
  2. stillbirth
  3. weakness
17
Q

What are the 3 forms of disease in dogs infected with Leptospira? What does this commonly result in? What 2 species cause this?

A
  1. hemorrhagic
  2. icteric
  3. uremic
    - kidney failure, severe liver disease, shock

L. canicola and L. icterohaemorrhiagiae

18
Q

How does Leptospira enter the host? How many cells are needed to cause infection?

A

enter through a scratch or mucous membrane

as few as 1-10 cells can cause fatal infection in susceptible hosts

19
Q

What part of Leptospira is anti-phagocytic until specific antibodies are produced?

A

outer sheath

20
Q

After Leptospira enters the bloodstream, where does it undergo initial replication? Where can they also infect and persist?

A

liver (4-20 days incubation)

  • reproductive tract
  • kidney
  • brain
  • eye
21
Q

What 3 things happen when Leptospira enters tissues? What does this suggest?

A
  1. vasculitis in small vessels
  2. hemorrhage
  3. fluid leakage

organism (sphingomyelinase) or host-mediated (cytokine) toxic factors

22
Q

What 4 things happen after the hematogenous spread of Leptospira to the lungs, brain, and kidneys?

A
  1. fulminating hepatic and renal disease, which can lead to death
  2. vascular damage leading to endothelial disruption via the release of TNF-α
  3. bile duct occlusion and jaundice
  4. nephritis
23
Q

In which animals is a carrier state without clinical signs common with Leptospira disease? What causes this?

A

rodents

antibodies are able to clear leptospires from the blood and all organs except the kidneys, where they are able to multiply in the lumen of nephritic tubules

24
Q

Where is Leptospira infection also able to happen in large animals? What does this result in?

A

uterus - can infect fetus and result in abortion or weak calves

25
Q

What are the 4 ways of transmission of Leptospira?

A
  1. exposure to contaminated urine through wounds or moist skin
  2. transplacental transmission (abortion and stillbirths in cattle, horses, pigs)
  3. milk
  4. semen

(some species are adapted to specific animals - Norway rats and L. ictohaemorrhagiae)

26
Q

Leptospira, silver impregnation stain:

A
27
Q

Leptospira, carrier state:

A
28
Q

What immunity is important against Leptospira? What is important to note about cows?

A

LPS antibodies
- early antibodies clear leptospires from blood by opsonization, but may persist in some tissues protected from antibodies (IgM, IgG serovar-specific antibodies)

cattle with antibodies to LPS may not be protected against another serovar —> may need IFNγ and a Th1 response

29
Q

What are the 2 major ways Leptospira infections are controlled?

A
  1. multivalent bacterin - know your local serovars, no bacterin contains all 200+ serovars
  2. prevent exposure to infected urine
30
Q

In what 5 ways is leptospirosis typically diagnosed?

A
  1. darkfield microscopy of urine, milk, water
  2. serology with a 4-fold change between acute and convalescent samples
  3. isolation - Fletcher’s, Ellinghausen’s, or Polysorbate liquid medium + 5-fluorouracil
  4. FA staining tissues
  5. histopathology of kidney, liver, and brain by silver impregnation staining
31
Q

What is the best serological test to diagnose Leptospirosis? How does Leptospira grow on in liquid media?

A

microscopic agglutination test (MAT)

diffuse zone, then a (Dinger’s) ring near the tobe of the tube (strict aerobe)

32
Q

What is the Ellinghausen-McCullough-Johnson-Harris medium used to isolate? What 7 ingredients are in it?

A

Leptospira

  1. various salts
  2. thiamine
  3. pyruvate
  4. glycerol
  5. bovine albumin
  6. tween 80
    7 B12
33
Q

What 2 things are important to note about antibiotic treatment of Leptospirosis?

A
  1. may not eliminate spirochetes from kidney
  2. penicilin and similar drugs may cause Jarisch-Herxheimer (endotoxic shock) reaction, so steroids may need to be added
34
Q

How is Leptospirosis spread to humans? Who are most at risk? What disease does infection cause?

A

wound infection, mucosal and conjunctival exposure

persons swimming in contaminated water, especially children

Weil’s disease - acute febrile illness with jaundice, hemorrhages, pulmonary distress, splenomegaly, nephritis, and death

Veterinary Bacteriology & Mycology (47 decks)

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