Leptospirosis

Question 1

Leptospirosis is caused by infection with antigenically distinct serovars of which species?

Answer 1

Leptospira interrogans sensu lato

Question 2

Before 1989, the genus Leptospira was divided into two species: L. interrogans (pathogenic) and what other species (saprophytic)

Answer 2

Leptospira biflexa

Question 3

How do incidental animal hosts (like dogs) typically respond to Leptospira infection compared to reservoir hosts?

Answer 3

They develop more severe clinical illness and shed organisms for shorter periods.

Question 4

What shape characterizes leptospires under a microscope?

Answer 4

Fine spirals with hook-shaped ends.

Question 5

Which of the following is NOT listed as one of the most commonly incriminated serovars in canine leptospirosis?
a) canicola
b) icterohaemorrhagiae
c) copenhageni
d) pomona

Answer 5

copenhageni

Question 6

Raccoons have been implicated as a source of which serogroup of Leptospira infections in the northeastern United States and Eastern Canada?

Answer 6

Grippotyphosa

Question 7

ow long can recovered dogs excrete Leptospira organisms in urine intermittently after infection?

Answer 7

For months.

Question 8

What environmental factors favor the survival of leptospires, leading to increased indirect transmission?

Answer 8

Stagnant or slow-moving warm water and neutral or slightly alkaline soil pH.

Question 9

What seasonal incidence is typically observed for canine leptospirosis?

Answer 9

Increased in the late summer and early fall.

Question 10

After entering the blood vascular space, where do leptospires typically spread and replicate?

Answer 10

In many tissues, including the kidney, liver, spleen, central nervous system, eyes, and genital tract.

Question 11

What is the approximate incubation period until clinical signs of leptospirosis appear in dogs?

Answer 11

Approximately 7 days.

Question 12

After initial spread, in which organ can Leptospira organisms persist and be shed in urine for weeks to months, even in the presence of serum antibodies?

Answer 12

Kidney.

Question 13

Which serovars have been associated with predominantly renal dysfunction and minimal liver involvement in dogs?

Answer 13

canicola, bratislava, and grippotyphosa.

Question 14

Younger dogs (under 6 months) seem to develop more signs of dysfunction in which organ during a leptospirosis outbreak?

Answer 14

Liver.

Question 15

What specific effect does an unsaturated fatty acid in a glycolipid fraction from leptospires have that might account for urinary potassium wasting?

Answer 15

It inhibits Na+-K+ ATPase.

Question 16

Chronic active hepatitis has been noted as a sequela to infection with which serovar in dogs?

Answer 16

grippotyphosa

Question 17

Which age group of dogs is generally more severely affected by leptospirosis?

Answer 17

Young animals.

Question 18

What type of dogs are most commonly affected by leptospirosis?

Answer 18

Large breed (over 15 kg), outdoor, adult dogs.

Question 19

What are the first clinical signs typically observed in acute leptospiral infections in dogs?

Answer 19

Pyrexia (fever), shivering, and generalized muscle tenderness.

Question 20

What are some coagulation defects and vascular injuries can be apparent in acute leptospirosis?

Answer 20

Hematemesis, hematochezia, melena, epistaxis, and widespread petechiae.

Question 21

Subacute leptospiral infections are characterized by fever, anorexia, vomiting, dehydration, and increased thirst, along with?

Answer 21

Reluctance to move and paraspinal hyperesthesia.

Question 22

What is a common finding on mucous membranes in dogs with subacute leptospirosis?

Answer 22

Congested, with petechial and ecchymotic hemorrhages.

Question 23

What renal functional deterioration is exhibited in subacute infections?

Answer 23

Oliguria or anuria.

Question 24

Which form of leptospirosis is more commonly associated with icterus in dogs?

Answer 24

Acute form.

Question 25

What can cause fecal color to change from brown to gray in icteric dogs with leptospirosis?

Answer 25

Intrahepatic cholestasis from hepatic inflammation.

Question 26

What is a common intestinal complication that occurs with some frequency in dogs with acute leptospirosis, presumably associated with GI inflammation?

Answer 26

Intestinal intussusceptions.

Question 27

What are common hematologic findings in typical cases of canine leptospirosis?

Answer 27

Leukocytosis and thrombocytopenia.

Question 28

Which electrolyte alteration is typically present in most cases of canine leptospirosis with renal and GI dysfunction? a) Hypernatremia and hyperkalemia. b) Hyponatremia, hypochloremia, hypokalemia, and hyperphosphatemia. c) Normal electrolyte balance. d) Hypercalcemia.

Answer 28

Hyponatremia, hypochloremia, hypokalemia, and hyperphosphatemia

Question 29

Which liver enzyme increase is often proportionally greater than that of ALT activity in canine leptospirosis?

Answer 29

Alkaline phosphatase (ALP).

Question 30

What gross external lesions may be seen in dogs that die of acute leptospirosis?

Answer 30

Congested and icteric mucous membranes with diffuse petechiae.

Question 31

On necropsy of animals dying of acute leptospirosis, what do the kidneys typically look like?

Answer 31

Enlarged, pale, yellow-gray, and bulge on the cut surface.