Leptospirosis

Question 1

What’s the causative agent of Leptospirosis?

Answer 1

Leptospira
- gram (-)
but has phenotype features of both gram (-) and gram (+) bacteria

Question 2

What’s the epidemiology of leptospirosis?

Answer 2

• reservoir hosts = small rodents
• resides in renal tubules and shed in the urine
• infection occurs via direct contact of MM or broken skin with infected urine
• indirectly from contaminated soil or surface water
• incidental host can develop acute, severe, and potentially lethal disease

Question 3

What’s the pathogenesis of leptospirosis?

Answer 3

• systemic infection = hematogenous spread
• doesn’t cause fulminant septic disease
• can evade the host immune system in the early stage of disease by inhibiting complement activation, until acquired immune response takeover to clear the infection
• so they persist in immune privileged organs like eyes and kidneys

Question 4

What are some effected lesions noted in acute leptospirosis infection?

Answer 4

kidney, liver, lungs

• predominately renal lesions = acute interstitial nephritis, tubular cell necrosis, apoptosis, and regeneration
• can cause a specific hypokalemic, nonoliguric form of AKI, due to inhibition of the tubular Na/K ATPase
• liver injury – elevated bilirubin
• leptospiral pulmonary hemorrhage syndrome
• intra-alveolar hemorrhage without marked inflammatory cell infiltration

Question 5

What are the most common clinical signs associated with leptospirosis?

Answer 5

due to kidney and liver injury

• anorexia, vomiting, lethargy, abdominal pain, diarrhea, jaundice, dehydration, stiffness/ MK pain, fever/ hypothermia, dyspnea/tachypnea, weakness, weight loss
• dogs rarely develop reproductive disorders

Question 6

What are some CBC/ chem changes for dogs with leptospirosis?

Answer 6

CBC: hemolysis, neutrophilia, left shift, lymphopenia, monocytosis, thrombocytopenia (DIC)
Chem: increased BUN, creatinine, liver enzymes
Electrolyte disturbance: hypo- or hyperkalemia, hypo- or hyperphosphatemia, hyponatremia, hypochloridemia.
U/A: isothenuria

Question 7

How can leptospirosis infection be confirmed?

Answer 7

positive culture
- microscopic agglutination test (MAT) = gold standard test for acute infection confirmation – best to test paired samples collected 1-2 weeks apart
- some dogs with acute infection can negative antibody (normal delay)
- some vaccinated dogs can be sero positive
- ELISA: quick, similar limitation as MAT
- PCR also possible, no interreference with vaccine

Question 8

How is leptospirosis treated?

Answer 8

• antibiotics and supportive therapy
• doxycycline

for pulmonary changes:
- supportive therapy
- avoid stress, overhydration/ hypervolemia, control of systemic hypertension

-renal recovery can take several months
- treat other dogs in the household with doxycycline for 2 weeks

Question 9

What’s the clinical signs of leptospirosis in cats?

Answer 9

c/s signs of acute disease = rare
- interstitial nephritis (experimental)

Question 10

How is leptospirosis prevented?

Answer 10

• vaccines