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47 Cards in this Set
- Front
- Back
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What type of agent causes leptospirosis?
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A spirochete (bacteria) with more than 200 serovars
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How do the pathogenic and non-pathogenic serovars of leptospires vary?
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Pathogenic serovars do not survive outside the animal hosts
-needs animal host to multiply |
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Is it more harmful to get a serovar of leptospires that are "host-adapted" to the animal that got it, or is it worse to get a serovar that is adapted to a different host?
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Much worse disease when get serovar that's adapted to a different host
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Why are animals so critical to the maintenance of pathogenic leptospires in a given area?
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Leptospires can persist in the renal tubules of animals without causing disease and can be excreted in the urine for prolonged periods of time
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What is so important about the leptospires persisting in the renal tubules?
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Allows the bacteria to evade the immune response while being sequestered in renal tubules
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Why is the prevalence of leptospirosis increasing?
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because no people do more outdoor things and take their dogs with them= higher likelihood of exposure
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What is the distribution of leptospirosis? And where is it most prevalent?
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Enzootic worldwide
-tropical and semitropical areas -disease of flooding -has to be rainy season -is in Oregon** |
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What seasons do we see leptospirosis?
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Summer or fall
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What type of soil do leptospires persist in?
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Alkaline soil
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How is leptospirosis transmitted?
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Leptospires are eliminated in the urine and enter the body through abrasions in skin and intact mucous membranes
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When do the clinical signs of leptospirosis develop?
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7 days post exposure
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What happens to the leptospires after infecting the animal?
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May clear the infection in 2-3 weeks
May develop chronic renal failure or chronic active hepatitis |
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In cats are leptospirosis infections usually clinical or subclinical?
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Subclinical= cats can shed leptospira in the environment
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Where do leptospira concentrate in the body?
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Liver or kidneys*****
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In dogs most cases of leptospirosis is clinical or subclinical?
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Subclinical
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How long do subclinical cases of leptospirosis excrete leptospira?
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Can be for years, even in treated patients
-carriers are problem for maintenance in env't |
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What are the 5 clinical signs of leptospirosis?
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1) Fever
2) Uveitis 3) Vomiting, diarrhea -renal failure, liver failure 4) Jaundice 5) Muscle pain (polymyositis) |
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What are 3 laboratory abnormalities seen on a CBC of an animal with leptospirosis?
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1) Leukopenia (acute)
2) Leukocytosis (subacute) 3) Thrombocytopenia |
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What are the 4 laboratory abnormalities associated with renal failure from leptospirosis?
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1) Increased BUN & creatinine
2) Cillindruria (casts in the urine) 3) Pyuria 4) Hematuria |
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What are 2 lab abnormalities seen in animals with liver failure from leptospirosis?
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1) Increased activity of ALT + ALP
-*ALP usually higher than ALT (60% of time) -ALP=cholestasis 2) Increased bilirubin |
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What abnormality in the lungs can be seen in patients with leptospirosis?
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Interstitial lung disease
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How do you diagnose leptospirosis?
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Clinical signs + serology
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What are 4 ways that serology can be used to diagnose leptospirosis?
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1) Detection of antibodies
2) Demonstration of the organism x dark-field or phase-contrast microscopy in the urine 3) Culture 4) PCR |
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What are 3 causes of antibody formation to leptospirosis?
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Active infection, previous infection or vaccination
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Leptospirosis vaccines may induce antibodies against L. ________.
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interrogans automnalis (pathogenic serovar)
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How can you tell an animal has an active leptospirosis infection via antibody detection? (3)
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-Microscopic agglutination test titer> 3200
-4 fold increase in titer over 2 wks -Positive IgM ELISA |
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True or false. Leptospira titers are usually an accurate diagnostic of leptospirosis.
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False, can be negative in an acute infection
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When can you pretty much assume a positive ELISA is really positive?
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*When animals have clinical signs
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How long do the antibodies against leptospira last from a vaccination?
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Up to 4 months
-still protected after 4 months -vaccine unlikely to get titer >3200 |
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Why can demonstration of the leptospira organism in dark-field or phase-contrast microscopy lead to false negatives?
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Intermittent shedding leads to false negatives
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What do you have to remember when sending a sample in for a culture on a suspect leptospirosis case?
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-culture before antibiotics
-place immediately in transport media -get to lab ASAP -pre-treatment w/ furosemide may increase yield |
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What 2 samples do you want to send in for PCR on leptospira? When do you prefer one over the other?
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1st 10 days= blood best
after 10 days= urine best -clinically: submit both |
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What are the 2 advantages of PCR for diagnosis of leptospirosis?
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1) Positive early on- before antibodies develop
-may be positive for years after recovery 2) very sensitive |
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Why is serology a poor predictor for leptospiruria?
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22% sensitivity
79% specificity |
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**What is the main thing to keep in mind when treating an animal with leptospirosis?
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Keep the animal alive and it will survive!!!
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What are the 2 components of treating an animal with leptospirosis?
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1) Fluid therapy
-Maintain hydration -*Preserve renal function 2) Antibiotics |
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What antibiotics are best for leptospirosis treatment?
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-Ampicillin or penicillin G initially (given IV)
-Doxycycline for 2 weeks after penicillin to eliminate the carrier phase |
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Why was the initial treatment for leptospirosis to give penicillin G IV first, followed by doxycycline? Why is this no longer necessarily the standard treatment?
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Because Penicillin G doesn't have very good penetration of the renal tubules so doesn't stop patient from shedding, doxycycline does penetrate the kidneys so decreases shedding, but may not eliminate it
-Doxy is now available as injectable so can just use doxy |
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What serovars of leptospira can potentially infect humans?
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All serovars
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What are 2 ways to prevent leptospirosis?
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1) Wear gloves
2) Vaccines |
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Why are vaccines given to leptospira positive animals?
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Can reduce severity of the disease but does not eliminate the carrier state
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How long does immunity from the leptospira vaccine last?
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1 year
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How does the vaccine protocol for leptospirosis change in high risk cases?
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-vaccine need to be given much more often
-at 12 wks, 15wks, 6 mo, 1 year |
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What are 2 high risk occupations for contracting leptospirosis?
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Veterinarians, farmers and abattoir workers
recreational activities in water |
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How do humans get infected with leptospira?
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Mucosal contact with water or soil contaminated w/ urine of infected animals
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Why do doctors have a hard time diagnosing cases of leptospirosis in humans?
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90% of cases of aniecteric and have very general signs including muscle pain, nausea, vomiting, diarrhea
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What do you call it when humans develop hepatitis and renal failure from leptospirosis?
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Weil's disease (10% of cases)
-long recovery in hospital |
