Order Spirochaetales Flashcards
What are the two families of importance in the Order Spirochaetales?
Spirochaetaceae and Leptospiraceae
Describe the morphology of Spirochaetales?
Protoplasm cylinder: includes the cytoplasm of the organism and accompanying cytoplasmic membrane
Cell wall: surrounds the protoplasm cylinder
Periplasmic flagella: attached to the protoplasmic cylinder and are inserted on both ends of the cell and overlap
Outer sheath: envelope covers all of the above
Do these stain well?
NO; they need a Darkfield or a phase-contrast microscopy
What was the only genus of things that we talked about for Spirochaetales?
Leptospira
Each species of Leptospira have several _____ and the basic taxonomic unit of Leptospira is the ______
Serovar
Serovar
What is the morphology of Leptospira?
Motile, spiral rods, with one or both ends hooked.
More tightly coiled than any other spirochaetes.
Growth of Leptospira prefers what?
Microaerophilic conditions
Occurs below the surface of semi-solid agar
What is the area of growth below the semi-solid agar called?
Dinger zone
Leptospira utilizes what for carbon and energy sources?
Long chain fatty acids and alcohols
What are some of the virulence factors Leptospira uses?
Viscotaxis
Cytotoxic factor: resists killing by neutrophils and complement
What is the natural habitat for Leptospira? Where is it often shed? How is it transmitted?
Proximal convoluted tubule of kidney
Shed in the urine
Direct contact with the urine or indirectly via contamination of water and food with urine
Where is leptospira most common?
Warm, moist environments
T/F Leptospira only requires a few seconds of contact time to penetrate mucous membranes
TRUE; can penetrate membranes of eyes, skin, nose, or mouth
What are the two different kinds of hosts when it comes to Leptospirosis?
Maintenance and Incidental
Describe what different effects the maintenance and incidental hosts will encounter with Leptospirosis?
Maintenance: do not usually become clinically ill. Antibody titers are never high and fall quickly. Can shed organism for a long time.
Incidental: high fever and acutely ill. Develop high antibody titers and shed for a time, but are not long term shedders
What kinds of clinical illness will you see in incidental hosts?
Acute hepatitis resulting in jaundice
Acute nephritis that can turn to chronic; common in dogs
Abortion, specifically when infected during last trimester
What are some of the resevoirs for some of the Leptospira serovars we are concerned with?
Icteroheamorrhagie: rats
Canicola: dogs
Pomona: swine
Hardjo: cattle
What are the common signs of Leptospirosis in cattle? What serovars are responsible?
Abortions without premonitory signs, stillbirths, weak calves, and low fertility syndrome
Hardjo-bovis, Pomona, Icterohaemorrhagiae
What are the common signs of Leptospirosis in swine? What serovars are responsible?
Similar to bovine signs.
Pomona; sheds large # of this is a common source of infection for other humans and animals
What are the common signs of Leptospirosis in horses? What serovars are responisble?
Abortions and anterior uveitis (moonblindness)
Pomona and others.
What are the common signs of Leptospirosis in dogs? What serovars are responsible?
Acute hepatitis, with acute to chronic interstitial nephritis. Can also see meningitis and pulmonary vasculitis.
Canicola and pomona will cause the development of chronic renal disease.
What causes the enhancement of Leptospirosis in Iowa?
Warm, wet conditions. Common in summers with a lot of rain or flooding.
T/F Some veterinarians have decided to stop vaccinating against this, leading to an increase in cases
TRUE; have seen anaphylactic reactions to some of the bacterins that are used
T/F Leptospirosis is an occupational hazard to veterinarians
TRUE; what the hell are we even doing?
Severe Leptospirosis infection in humans is often associated with what clinical signs due to what serovar?
hepatic or renal failure
Icterohemorrhagiae
T/F Human to human spread of Leptospirosis is frequently seen
FALSE; it is most commonly seen in rats to human and dogs to human spread
What are some of the diagnostic tools that can be used to detect Leptospirosis infection?
Serological, which can detect antibody to Leptospires in serum: Microscopic agglutination test, PCR of urine, and ELISA
Culture: needed for definitive identification of infecting serovar, as it is the most accurate method
Can also use Darkfield microscopy of urine or silver staining
T/F Immunization against Leptospira protects the host against clinical infection
FALSE; only protects against clinical disease
What are some of the vaccines that are available for dogs?
Multivalent bacterins are available for many animals and dogs, cattle, and swine are most commonly vaccinated.
There are no vaccinations for horses or humans
How do you treat Leptospirosis?
Ampicillin/Penicillin first to kill the organisms in systemic circulation followed by Tetracycline
