Leptospira

Question 1

Characteristics

Answer 1

-Class Spirochaetia
-biocontainment level 2
-2 chromosomes
-culture challenging because slow growing (weeks)
-inhabit many hosts

Question 2

Habitat

Answer 2

1. Animal hosts in renal tubules
   -shed in urine and contaminate the environment
   -wildlife, people, domestic animals, bats
2. Water associated (rivers and ponds)
   -readily survives in bodies of water (linked with flooding)
   -**susceptible to desiccation **moisture plays a role in transmission so keep animal housing dry and clean

Question 3

Leptospirosis incidence

Answer 3

-associated with tropical countries, low in Canada
-not nationally reportable disease

Question 4

Taxonomy

Answer 4

-divided into species (genetics) and serovars (surface antigens)

-not a one to one relationship. Serovars can be in multiple species
ex. Pyogenes serovar in both L. santarosai and L. interrogans

Question 5

Virulence factors

Answer 5

**Invade tissues through moist/soft skin, mucous membranes or by ingestion

1. Adhesions
2. Surface surviving proteins- unknown role, but needed for pathogenic strains
3. Haeme oxygenase- use of haeme as Fe source
4. Flagella- motility

Question 6

2 main things you see with Leptospira

Answer 6

-icterus
-renal disease

Question 7

Leptospira Hardjo

Answer 7

-cattle
-infections most often without overt clinical signs but may result in reproduction problems and milk drop
-shed in urine

Question 8

Clinical signs of Leptospira Hardjo

Answer 8

-none OR:
-reproductive failure
-abortion
-milk drop syndrome (mastitis, flabby udder, yellow or red tinged milk)
-chronic genital infection

Question 9

Leptospira Pomona in cattle

Answer 9

-Causes acute infections
>fever, anorexia, lethargy, decreased milk production
>haemolytic anemia, intravascular hemolysis, petechiation
>icteric infections
>necrotizing placentitis

Question 10

Treatment and Prevention of Leptospira Pomona

Answer 10

-depends on serovar type
>antimicrobials
>supportive care (IV fluids for renal failure, NSAIDs, blood transfusion)

-prevention
>vaccines
>maintaining clean dry environment
>eliminate carriers

Question 11

Leptospira Pomona in pigs

Answer 11

-persists in kidney and sheds in urine
-often seen in gilts

Acute: pyrexia, listlessness, often unrecognized
Chronic: abortions, economic loss

Question 12

Are there other serovars of Leptospira in pigs?

Answer 12

L. Icterohaemorrhagiae = from rats

L. Canicola

L. Australis

L.Grippotyphosa

L. Hardjo

Question 13

What is a Differential Dx for Leptospira and vice versa?

Answer 13

Multifocal interstitial nephritis = Milk-spot Kidney

Question 14

Treatment for Leptospira in pigs

Answer 14

-antimicrobials for outbreaks but not effective at eliminating serovars from herds

-replacement stock is likely source
-biosecurity= skunks implicated in outbreaks
-vaccines
-interruption of transmission

Question 15

Leptospira in dogs

Answer 15

-usually younger animals more severe
-severity not linked with Serovar
-common in hounds and working dogs= more wildlife contact or contaminated water

Question 16

Clinical signs of Leptospira in dogs

Answer 16

-pyrexia
-vomiting, dehydration, diarrhea (melena)
-peripheral vascular collapse, tachypnea, poor capillary perfusion
-icterus (hepatic damage)
-peracute infections can result in massive leptospiremia (blood supply!!) and rapid death

-tubulointerstitial nephritis and renal cortical hemorrhage often seen in necropsy

Question 17

Distribution of Leptospira in dogs

Answer 17

-higher on East and West Coasts= USA

-few cases in Vancouver, Southern Ontario, Maritimes
*highest in S. Ontario and Nova Scotia

Question 18

Treatment and prevention of Lepto in dogs

Answer 18

-Supportive treatment

-Antimicrobials
>Penicillin for acute disease
>tetracyclines, macrolides or aminoglycosides for eliminating carriers

-vaccines available- prevents disease but does not get rid of zoonotic risk/carrier states

Question 19

Leptospira in people

Answer 19

-acute onset of fever, headache, muscle pain, conjunctivitis; can mimic dengue fever
-icterus

-Fatality rate: 1-% with treatment; 20% if hepatorenal failure without dialysis
-no vaccine for people

-Linked with occupational exposure
>workers near water and animals
>recreational contact with water (swimming, rafting, wading)

-likely in tropical climates

Question 20

Transmission of leptospira in humans

Answer 20

-acquired by contact of skin or mucous membranes with contaminated water, soil, vegetation, urine

-linked with travel! (wash hands, avoid animals, discuss antimicrobial prophylaxis) AND heavy rainfall

**Rare in N. America
100-200/year in USA, 1-3 cases in Canada

Question 21

Sample collection

Answer 21

-whole blood
-urine
-tissue samples from kidney or liver (they live for days if not frozen)
-abortuses/placental tissues

**Use PPE

Question 22

Lab ID

Answer 22

-detected in fresh urine by dark field microscopy or immunostaining of urine sediment

-PCR on urine

-serological testing= microscopic agglutination test (MAT)

-isolate from blood early in infection
*culture difficult because need special media, long incubation time
*then ID by molecular methods

-fluorescent antibody (liver and kidney)

Question 23

How to choose which Lab ID test?

Answer 23

Depends on timing of infection
-specific biology of the pathogen will affect what will be present and what test will be the most useful

Question 24

Zoonoses

Answer 24

-Animals to animals and animals to people
*broad host range; very high in rats= spread

• PPE needed to avoid direct contact with infected animals urine

Question 25

Treatment options

Answer 25

Many drugs can be used
-be aware of what species you are treating and what drug withdrawal times they have

-Streptomycin & Doxycycline can be used for clearing carriers

DO NOT USE Chloramphenicol or sulfonimides (not intrinsic resistance but they don’t work clinically)