Module 9.9 Part B

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Curved Gram-negative rods and spirochetes:

Curved Gram-negative rods and spirochetes Module 9.9 Part B


Spirochaetaceae The spirochaetes


Spirochaetaceae Slender, helically coiled, spiral organisms Wrapped around internalized flagellum Move corkscrew, flexing or serpentine Rarely Gram stain Use dark field or silver stain often 4 genera: Borrelia, Brachyspira, Leptospira, Treponema,

Bruno, a very sick Jack Russell:

Bruno, a very sick Jack Russell


Bruno November 2010, Guelph Bruno didn’t get up in morning, lay in bed shivering, some vomit in kitchen “Must have eaten something” That evening, still vomiting but more frequently, shivering, painful when felt his muscles Not peed all day Brought to “emerg”

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Elevated creatinine, BUN Elevated CPK, muscle enzymes Elevated bilirubin, alkaline phosphatase Bruno has acute renal failure and hepatitis

Bruno has leptospirosis:

Bruno has leptospirosis




Leptospira Aerobic spirochetes 6-20 x 0.1 μ m Hooked ends (interrogation mark = interrogans old name) Grow in semi-solid rich media at 28-30 C, 10-14 days (or much longer), specialist labs Dark field, FA, not Gram Antigenic classification, old : 23 serogroups, 250 serovars (named) eg L. interrogans serovar hardjo Genetic classification, new : 8 species, subdivided into serovars eg L. borgpetersonii serovar hardjo Named for serovar


Leptospira Different serovars adapted to reservoir ( maintenance) hosts Characteristically prolonged, lifetime, kidney ( + genital tract) carriage Non-maintenance (“accidental” = “incidental”) hosts a few weeks in kidneys Home PCT of kidney; shed urine Fastidious bacteria ; survive only in wet (moist), warm environments 4-6 weeks; “ fall fever ”, “mud fever”

Leptospiral serovars and adaptation in Canada:

Leptospiral serovars and adaptation in Canada pomona Pig, skunk grippotyphosa Raccoon, skunk, rodents canicola Dog hardjo Cattle, sheep bratislava Pig, horse, dog icterohaemorrhagiae Rat


Leptospirosis Self-contained infections within maintenance hosts Spill over to incidental host Broad host range pathogen; mildest disease in maintenance host Classic “iceberg” infection; most subclinical or chronic Invasive, bacteremic disease: localization liver, kidney, CSF, eye

Leptospirosis: The iceberg:

Leptospirosis: The iceberg Peracute DIC, haemorrhages, haemoglobinuria, death Acute, subacute Fever, hepatitis, nephritis, abortion (mastitis) Chronic Abortion; chronic nephritis (pig, dog); recurrent uveitis (horses). Infertility pigs, cattle?? Subclinical Antibody rise only (or mild ‘flu like illness)


Leptospirosis Pig pomona : Abortion; chronic nephritis bratislava : small litters, stillbirth, infertility Cattle pomona : abortion, haemoglobinuria , mastitis hardjo : abortion, stillborn, weak calves; mastitis


Leptospirosis Horse pomona: abortion; recurrent uveitis (periodic ophthalmia) Dogs canicola: acute or chronic renal failure (interstitial nephritis) Grippotyphosa , pomona : fever, hepatitis, acute renal failure

Resurgence of leptospirosis in dogs:

Resurgence of leptospirosis in dogs

Recent decline in canine leptospirosis: Vaccination?:

Recent decline in canine leptospirosis: Vaccination?

Diagnosis of leptospirosis:

Diagnosis of leptospirosis Not easy Mostly serology using paired serum samples (microscopic agglutination test). Can be hard to interpret: 4X increase Direct demonstration: Dark field; immunofluorescence; PCR

Control of leptospirosis:

Control of leptospirosis Annual serovar-specific vaccines (“5 or 6 way”); new canine vaccines Treatment: Ampicillin; Minocycline Vector control

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