24 – Leptospira Flashcards

1
Q

Microbiological characteristics

A
  • Spirochales and Brachyspirales
  • Biocontainment level 2
  • *2 chromosomes
  • Culture is challenging: slow growing
  • Causes a constellation of disease syndromes in MANY species
    o Complex epidemiology
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2
Q

Leptospira scanning electron micrograph

A
  • ‘characteristic’ crooked ends
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3
Q

Natural host or habitat

A
  • Maintained by animal hosts
    o Persist in renal tubules, shed in urine, contaminate environment
  • Water associated (flooding)
    o Susceptible to desiccation
  • *moisture is very important for transmission!
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4
Q

How can humans get Leptospira?

A
  • Direct or indirect contact with urine
    o Rodents
    o Water
    o Wildlife
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5
Q

Taxonomy: basic

A
  • Divided into species: genetic relatedness
  • Divided into serovars (Capitalized and not italics)
    o Defined by presence of surface antigens
    o Not all are found in only one species, LOTS of overlap
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6
Q

Virulence factors

A
  • Invade tissues through moist/softened skin, mucous membranes or ingestion
  • Adhesions
  • Surface surviving proteins
  • Haeme oxygenase
  • Flagella
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7
Q

What are the ‘big’ clinical signs seen with Leptospira in many species

A
  • ICTERIC
  • RENAL DISEASE
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8
Q

What might Leptospira Hardjo cause in cattle?

A
  • Reproductive problems
    o Reproductive failure
    o Abortion
  • Milk drop syndrome
    o Mastitis
    o Flabby udder
    o Yellow or red tinged milk
  • *most often WITHOUT SIGNS
  • *chronic genital infection is common
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9
Q

How is Leptospira Hardjo shed in cattle?

A
  • Urine: possible for life
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10
Q

What are the clinical signs you see with acute infections of Leptospira Pomona in cattle?

A
  • Fever, anorexia, lethargy, decrease milk production
  • Haemolytic anemia, intravascular hemolysis, petechiation
  • Necrotizing placentitis
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11
Q

How is Leptospira Pomona in cattle treated?

A
  • *depends on which serovar
    o Antimicrobials
    o Supportive care (IV fluids, NSAIDs, Blood transfusion)
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12
Q

What is the prevention for Leptospira Pomona in cattle?

A
  • Vaccines
  • Maintain clean, dry environment
  • Eliminate carriers (treat or cull)
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13
Q

Where does Leptospira Pomona in pigs persist and how is it shed?

A
  • Persists in kidney
  • Shed in urine
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14
Q

What are the clinical signs typically seen in gilts with acute Leptospira Pomona?

A
  • Pyrexia, listlessness
  • May go unrecognized in herd
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15
Q

What are the clinical signs typically seen in gilts with chronic Leptospira Pomona?

A
  • Abortions
  • Considerable economic loss
  • *can get serovars from other species
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16
Q

What is a differential diagnosis for multifocal interstitial nephritis?

A
  • Leptospira
  • *milk-spot kidney
17
Q

How do you treat Leptospira in pigs?

A
  • Antimicrobials important in outbreaks
  • Apparently not effective at eliminating serovars from hers which are maintained by pigs
18
Q

What are the control measures for Leptospira in pigs?

A
  • Replacement stock=mostly source
  • Biosecurity
    o Skunks have been implicated in outbreaks
  • Vaccination
  • *Interruption of transmission is important
19
Q

What is significant with dogs infected with Leptospira?

A
  • Younger animals more severely affected
  • *severity NOT correlated with serovar
    o Serovars vary geographically
  • *Nova Scotia and Southern Ontario=highest prevalence areas in Canada
20
Q

What are the clinical signs of Leptospira in dogs?

A
  • Pyrexia
  • Vomiting, dehydration, diarrhea
  • Peripheral vascular collapse, tachypnea, poor capillary perfusion
  • Icterus
  • Peracute infections=massive leptospiremia and rapid death
21
Q

What type of dogs do you most commonly see Leptospira in?

A
  • Hounds and working dogs
    o Those with more wildlife or contaminated water body contact
22
Q

How do you treat Leptospira in dogs?

A
  • Depends on severity: supportive treatment
  • Antimicrobials
    o Penicillin: acute disease
    o Tetracyclines, macrolides, aminoglycosides: NEEDED TO ELIMINATE CARRIER STATE
23
Q

How do you prevent Leptospira in dogs?

A
  • Vaccines are available
    o **May prevent disease, but NOT carrier state (ZOONOTIC RISK)
  • Avoid contact with reservoirs
24
Q

What does Leptospira cause in humans?

A
  • Acute onset fever
  • Headache
  • Muscle pain
  • Conjunctivitis
  • *can mimic Dengue
  • Icterus: 5-10% of cases
25
Q

What is the case fatality of Leptospira in humans?

A
  • 1-5% without treatment
  • Up to 20% if hepatorenal failure without dialysis
26
Q

What are the occupational exposures with Leptospira in people?

A
  • Workers on farms, mines, sewers, abattoirs, vet, fish, dairy, military
  • Association with recreational contact with water
  • Swimming, wadding, rafting
  • *more likely in tropical climates
27
Q

How do humans acquire infection of Leptospira?

A
  • Contact of skin or mucous membranes with contaminated water, soil, vegetation, urine
    o Incubation 10 days
  • *rare in NA
  • *travel associated is important
  • NO vaccine licensed for use in people in Canada
28
Q

How can you prevent travel associated Leptospira in humans?

A
  • Wash hands
  • Avoid animals
  • Discuss antimicrobials prophylaxis with travel clinic (DOXYCYCLINE)
  • Be aware and monitor your health
29
Q

Sample collection

A
  • Whole blood
  • Urine
  • Tissue samples (kidney, liver)
  • Abortuses/placental tissues
30
Q

Sample handling

A
  • PPE!
31
Q

Lab ID

A
  • Detected in fresh urine with dark field microscopy of immunostaining of urine sediment
  • PCR on urine
  • Serological testing
  • can be isolated from blood EARLY IN INFECTION
  • fluorescent antibody (liver and kidney)
32
Q

Serological testing

A
  • microscopic agglutination test (MAT)
    o mix serum with known cultures of Leptospira=look for agglutination
33
Q

Can be isolated from blood early in infection: culture is difficult

A
  • requires special media
  • potentially long incubation times (Hardjo requires 6 months)
  • isolates then ID using molecular methods
34
Q

There are so many tests, how do you select the best one for your patient?

A
  • Partially based on WHEN in course of disease your patient is
  • Need to know biology of the pathogen!
35
Q

Zoonotic/interspecies transmission

A
  • Animal to animal+animal to human very important!
  • Very broad host range
  • Europe=beware of hedgehog
  • *important zoonoses
    o PPE!
36
Q

Treatment options

A
  • Wide variety of drugs can be used
    o Beware of what species are you treating and what the drug withdrawal times may be
  • Clearing carriers: streptomycin, doxycycline
  • *chloramphenicol and sulfonamides NOT recommended