leptosporosis Flashcards
(14 cards)
What causes canine leptospirosis and which serovars are involved?
Canine leptospirosis is caused by spirochetes of Leptospira interrogans (L. Icterohaemorrhagiae, L. Canicola, L. Pomona, L. Bratislava) and Leptospira kirschneri (L. Grippotyphosa).
Describe the epidemiology and reservoirs of canine leptospirosis.
Seen worldwide in domestic and wild animals; rats (L. Icterohaemorrhagiae), dogs (L. Canicola), pigs (L. Pomona), cattle (L. Hardjo), horses (L. Bratislava). Spread via contaminated urine in moist environments.
How has the clinical incidence of leptospirosis changed over time?
Declined in 1970s and 80s; increased since 1990s; all breeds affected today. Studies show rising cases of serovars Copenhageni and Bratislava.
What are the common clinical signs of canine leptospirosis?
Lethargy, anorexia, vomiting, jaundice, fever, abdominal pain, PU/PD, diarrhoea. L. Canicola causes nephropathy; L. Icterohaemorrhagiae causes hepatitis and pulmonary haemorrhage.
Explain the pathogenesis of leptospirosis.
Leptospiraemia lasts 1 week, localises to organs including liver, kidneys. L. Canicola causes renal inflammation; L. Icterohaemorrhagiae causes liver haemorrhage. Infection persists in renal tubules causing shedding.
What is Leptospiral Pulmonary Haemorrhage Syndrome (LPHS)?
Severe pulmonary haemorrhage seen in dogs and humans. Pathogenesis involves endothelial damage by Leptospira, altered epithelial sodium transport, immune complex deposition.
How is canine leptospirosis diagnosed?
Clinical signs, dark field microscopy, silver staining, immunofluorescence of urine, PCR (blood/urine), serology (MAT). PCR allows early detection but sensitivity varies. MAT gold standard.
What are the limitations of serology (MAT) in diagnosing leptospirosis?
MAT titres ≥1:400 or 4-fold rise confirms diagnosis. Vaccine-induced antibodies may interfere; early sampling can yield false negatives; paired samples highly recommended.
How should PCR testing for leptospirosis be timed?
Best before antibiotic therapy. False negatives can occur due to early treatment or intermittent shedding. Urine PCR preferred after 7–10 days of infection.
How is canine leptospirosis treated?
Early antibiotics: penicillin, erythromycin, tetracyclines. Severe cases need IV fluids, electrolyte correction, possibly blood transfusions. Tetracyclines post-recovery to clear renal carrier state.
Describe the vaccination strategies for canine leptospirosis.
Killed whole-cell bacterins for serovars L. Canicola, L. Icterohaemorrhagiae; newer vaccines include L. Copenhageni, L. Bratislava. Two doses starting at 6–9 weeks, annual revaccination required.
What concerns exist regarding tetravalent vaccines for leptospirosis?
Slightly higher adverse event rate (0.069%) vs. bivalent vaccines (0.015%). Still classified as rare (<10 in 10,000); comparable to other core vaccines.
What is the zoonotic potential of canine leptospirosis?
L. Icterohaemorrhagiae causes Weil’s disease in humans. Humans infected from contaminated water or dog urine. Severe cases involve renal/hepatic failure and death if untreated.
What is the emerging significance of leptospirosis in cats?
Reported in hunting cats exposed to rodents. Similar disease to dogs but less common; under research for its role in feline kidney disease and as an asymptomatic carrier.
