Resident Friday Rounds

Question 1

What is the etiologic agent of the visceral form of leishmaniosis?

Answer 1

Leishmania infantum (L. chagasi)

Question 2

In North America, Leishmaniasis has mostly been document in which dog breed?

Answer 2

Fox Hounds

Question 3

Main source of Leishmaniosis infection

Answer 3

Sand fly

*however, there are various non-vector related ways of transmission

Question 4

Dogs with Leishmaniosis that form a _____ response clear the infection, and those with a _____ response become persistently infected.

Answer 4

TH1 response (yFN, IL12, NO) –> cell-mediated immunity

TH2 response (IL4, IL10) –> humoral immunity

Question 5

Which cell is the primary resident cell for Leishmania that contains amastigotes?

Answer 5

Macrophages

Question 6

Leishmania parasites alternate between two distinct developmental stages: the flagellated, motile _____ form residing in the midgut of ____ vectors, and the non-motile ______ form that reside within phagolysosomal vesicles of the vertebrate host _____.

Answer 6

promastigote

sandfly

amastigote

Question 7

Leishmania can lead to type ___ hypersensitive reaction, causing insoluble Ab-Ag complex. A common organ system that gets affected and often results in death of the patient is ________.

Answer 7

III

Kidneys –> Renal disease (others: eye, joints)

Question 8

Diagnosis of Leishmania - what are the best areas to aspirate for cytological diagnosis of Leishmania?

Answer 8

LNs, spleen, liver, bone marrow

*rarely can be found in blood

Question 9

How to diagnosis Leishmania?

Answer 9

• Cytology
• Serology - IFA is the standard test
• PCR (qtPCR)
• Histopath - not as good as cytology

Question 10

IFA of Leishmania can lead to false positive results from ____ and false negative results from ______.

Answer 10

False + from Trypanosoma spp.

False - results from delayed seroconversion (5 months)

*remember that vaccinated animals will have a positive test due to antibodies.

Question 11

Typical and frequent abnormalities found on bone marrow cytology in canines infected with Leishmania sp.?

Answer 11

Typical: erythroid hypoplasia, myeloid hyperplasia, macrophage proliferation/hyperplasia, intracytoplasmic amastigote, plasmacytosis

Frequent findings: Megakaryocyte hyperplasia, Secondary Dysmyelopoiesis (dyserythropoiesis or dysmegakaryopoiesis, occasionally dysgranulopoiesis)

*VetClinPathol 2016, 45:522-578

Question 12

Which chromagen is used for IHC detection of amastigotes in canine leishmaniasis?

Answer 12

Diaminobenzidine chromogen

Question 13

Allopurionol is a drug used to treat leishmaniasis. It can form ____ crystals in urine and possibly urolithes.

Answer 13

Xanthine crystals

Question 14

A seropositive or PCR-positive dog with ____ CD4/CD8 ratio is expected to be more predipsosed to develop clinical signs than a similar dog with a CD4/CD8 ratio in the reference range.

Answer 14

Low

*thought to be due to decreased CD4 lymphocytes

Question 15

Most pathogenic babesia species is?

Answer 15

B. canis rossi

Question 16

Most common clinical manifestatino of babesia?

Answer 16

Fever, Haemolytic anemia, splenomegaly, thrombocytopenia

Question 17

What is red biliary syndrome in canine babesia infections?

Answer 17

This is a syndrome of paradoxical hemoconcentration with intravascular hemolysis and is a rare complication in canine babesiosis. The cause is thought to be vasculitis and fluid shifts leading to relative hemoconcentration despite severe hemolysis. Red biliary is often associated with both AKI and cerebral babesiosis and has a guarded prognosis. Vet Med (Auckl). 2015; 6: 119–128.

Question 18

Diagnosis of babesia

Answer 18

• Cytology
• IFA - but cross reactivity
• ELISA - no commercial test available
• *PCR* - preferred test, better lower detection threshold
• Culture - not utilized in clinical settings because it takes weeks

Question 19

Which canine speices has a higher prevalance rate of Babesia gibsoni? Why?

Answer 19

American Staffordshire and American pit bull terriers - thought to be due to fighting between dogs - serves as a mode for mechanical transmission

Question 20

Dogs become infected with Babesia spp. when they are inocculated with _____ in tick saliva or ingest the tick . After inoculation, Babesia ____ invade RBCs where they multiple asexually by binary fission. This results in _____ which rupture the RBC and go to invade other RBCs.

Answer 20

Sporozoites

Sporozoites

Merozoites

Question 21

Canine splenectomy can exacerbate both parasitemia and clinical disease from infection with Babesia sp.. T/F

Answer 21

True