Leptospira

Question 1

Can lepto be seen with a light microscope?

Answer 1

No, they are >0.1 um wide

- view under dark-field microscopy and by phase contrast microscopy

Question 2

How does lepto invade?

Answer 2

Through INTACT mucosa of alimentary tract, eye and genitalia, or abraded/moist skin after contact with urine, water, food, or coitus

Question 3

What is the natural habitat for lepto?

Answer 3

Lumen of proximal convoluted tubules of animals that become latent or chronic (asymptomatic) carriers
- lepto is protected from humoral antibodies and is easily shed in urine

Question 4

Vaccine

Answer 4

Bacterins (whole cell and killed) are available

- prevent abortion and acute clinical signs, but not infection, renal colonization and shedding

Question 5

Bacterins stimulate ______ immunity

Answer 5

IgG

- may see IgM response for 1-2 months

Question 6

How long should you vaccinate?

Answer 6

2-3 times a year depending on environment

Question 7

You are inducing a ________ when you vaccinate

Answer 7

Carrier state

Question 8

When does inflammation occur?

Answer 8

When the lepto escapes from the renal tubule into the interstitium

Question 9

Antibiotics

Answer 9

Required to penetrate the renal tubules and to clear a carrier state

• penicillin G or ampicillin
• tetracyclines: 1 kg/ton feed (swine)
• streptomycin: 25 mg/kg to clear carrier state!!!
• chlorampenicol: dogs
• erythromycin
• doxycycline: people

Question 10

It takes ______ for an aminoglycoside to clear from cattle

Answer 10

1. 5 years

- withhold from slaughter

Question 11

Serology for bovine lepto

Answer 11

• rapid plate method: screen with killed organisms (1:50 dilution)
• microscopic agglutination/lysis test (MALT): used in all species
• 10 cows or 10% of herd to be tested with both normal and suspect animals

Question 12

Perform a ______ in acute and convalescent serums

Answer 12

4 fold rise

Question 13

Presence of antibodies in an individual serum

Answer 13

Only indicates past exposure

• an infected animal could fail to develop antibodies
• some are positive for life, others become negative in a few months

Question 14

_______ does not reflect shedder status

Answer 14

Presence or absence of titers

Question 15

Canine lepto serology

Answer 15

Screen with commercial killed antigen plate test

• if positive: plate dilution test
• if positive at 1:64 or 1:128: send to state lab for confirmation with MAL
• MAL: positive at 1:300 or higher = significant

Question 16

Culture

Answer 16

Urine is best

- blood or milk is not feasible

Question 17

Animal inoculation

Answer 17

Is only done for rabies!!

Question 18

Microscopic agglutination/lysis test

Answer 18

Requires live organisms!

• IgG and IgM detected is serovar specific
• carried out in a 96 well plate and viewed using inverted phase microscope

Question 19

Titer

Answer 19

Least amount of serum that produces a positive result in a serologic test
- aka: highest dilutino of serum that causes lysis of lepto

Question 20

Lepto commonly requires _____ for testing due to difficulty to grow

Answer 20

Indirect serology

Question 21

T. cuniculi

Answer 21

Causes vent disease in rabbits

• syphilis, ventral and perineal scabs
• transmitted via STD
• distributed worldwide

Question 22

Serpulina hyodysenteriae

Answer 22

Swine dysentery

• transmitted via fecal oral
• distributed worldwide
• only of the few GI diseases caused by spirochetes

Question 23

Axial filaments

Answer 23

Terminate in a hook, giving cells and S or C shape

- actin/myosin like components for contractility

Question 24

Borrelia burgdorferi

Answer 24

Cause of lyme disease

• host: mammals, birds
• transmission: I. scapularis (is not found in the south)
• disease: EM, arthritis, carditis, neuroborreliosis
• found in US