Infectious Dz - Lepto Flashcards
What type of bacteria is Leptospira?
a gram negative spirochete
What are the two main pathogenic Leptospira species in dogs?
L. interrogans and L. kirschneri
What are the specific reservoir hosts for Leptospires?
Rats, mice, muskrats, opossums, and squirrels
What can kill Leptospira?
frost, disinfectants, and UV radiation
Where can Leptospira survive for long periods of time?
water and wet soil
True or False: Seasonality of Leptospirosis outbreaks are associated with rainfall
True
Where is Leptospirosis distributeed?
Across the US but here are high incidences around the great lakes, in the Mississippi and Ohio river valley
When do Leptospirosis outbreaks most commonly occur?
In the fall
How does infection with Leptospirosis happen?
Infection is by ingestion or contact with contaminated water/urine
also transplacental and venereal
What is the rout of entry of Leptospira?
intact mucosal surfaces or skin abrasions
In a recent study, what dogs have the highest prevalence of Leptospirosis?
In dogs less than 15 pounds
Yorkies are the highest prevalence breed
Bottom line, what dogs can get Leptospirosis?
Any dog
Explain the infection timeline of Leptospirosis?
Day 0 - mucosal penetration, multiplication in vasculature
Day 3-4 - Multiplication
Day 5-6 - Vascular damage and thrombocytopenia
Day 7-8 - Clinical disease
Day 10 - Antibody titer increases
Day 12 - renal colonization
Day 14-15 - Leptospiruria
What clinical feature is often overlooked in patients with Leptospirosis?
a transient fever
What other clinical features do patients with Leptospirosis have?
Renal injury (50-80%) Hepatic injury (14-47%) Lung injury (2%)
What clinical signs are associated with Leptospirosis?
PU/PD, uremia, icterus, tachypnea, cough, harsh lung sounds, uveitis and bleeding tendencies
How can you diagnose Leptospirosis?
Minimum database, coagulation panel, imaging, dark field microscopy, culture, PCR, and serology
What will you find on minimum database in patients with Leptospirosis?
Thrombocytopenia, azotemia, increased ALT/ALP, hyperbilirubinemia, and signs of tubular damage (glucosuria and proteinuria)
What may you find on a coagulation panel in patients with Leptospirosis?
Increased PT/PTT
What may you see on thoracic radiographs in patients with Leptospirosis?
Interstitial to nodular pattern
What may you see on ultrasound in patients with Leptospirosis?
Perirenal, abdominal fluid, pyelectasia, and hepatic changes
Why would you want to use dark-field microscopy to diagnose Leptospirosis?
To examine live organisms in urine
Why is culture not commonly performed to diagnosis Leptospirosis?
because it is a long process
What does PCR detect?
DNA of the organism
Why would you want to do PCR for Leptospirosis diagnosis?
because it can allow for an earlier diagnosis over serology
Does a negative PCR result rule out Leptospirosis?
no
What can cause a false-negative Leptospirosis?
Administration of 1-2 doses of antibiotics
What serologic tests can be done to diagnose Leptospirosis?
Microscopic agglutination test (MAT), SNAP Lepto, and Witness Lepto
What does the Microscopic Agglutination Test based on?
Agglutination of live cultures in contact with serial dilutions of the patients serum
What is a positive MAT result?
Titer of >1:1600 or 4-fold increase in convalescent antibody titers
What should always be done if you chose MAT to diagnose Leptospirosis?
You always need to do a convalescent titer (second titer) with >10-14 days in between
What can cause false positives in a MAT test?
previous exposure and vaccination
What can cause false positives in a MAT test?
Serovar not included on the test panel and early testing
What does SNAP Lepto detect?
LipL32 proteins
Can vaccination affect SNAP Lepto results?
yes - cross reactions with vaccine antibodies is reported in 24% of cases
If a patient has Leptospirosis, why can they get a negative SNAP Lepto result?
because it is early in the infection
What does Witness Lepto detect?
IgM antibodies against whole-cell extracts
Does Witness Lepto cross-react with vaccination?
It can, but it is less likely
If a patient has Leptospirosis, why can they get a negative Witness Lepto result?
because it is early on in the infection
How long can vaccination titers persist in patients?
up to 1 year post vaccination
Which test is the best one?
Each test has its own advantages/disadvantages
Consider using a combination of tests as well as your clinical assessment
What is the gold standard treatment for leptospirosis?
Doxycycline for 2 weeks
Aside from doxy, what is used to treat leptospirosis?
Ampicillin/amoxicillin
Why would you want to use Ampicillin/amoxicillin?
it clears bacteremia
What is the prognosis for Leptospirosis?
Good if treatment is initiated early - antibiotics, IV fluids, and supportive care
What serovars are there Lepto vaccines for?
Icterohemorrhagiae, canicola, grippotyphosa, and pomona
Ideally, when should a Lepto vaccine be performed?
a few months prior
What is the efficacy of the Lepto vaccine?
It has been shown to decrease shedding and protect against disease when challenged with vaccinated serovar
What are the public health risks with Leptospirosis?
It is zoonotic - special precautions should be taken with all dogs with AKI or acute hepatopathy of unknown etiology
What precautions can be taken when dealing with a patient with suspect Leptospirosis?
Inform clients and personnel
Wear gloves at all times
Disinfect urine and sides of urination with iodine or bleach
Have designated areas for Lepto patients
Can cats get Leptospirosis? How?
Infection is possible by ingestion of prey and contact with infected dogs
In most cases, cat infection is _______.
subclinical
Is vaccination in cats recommended?
no
