Infectious Agents

Question 1

What domestic species gets cyauxzoonosis? What cells are infected by cyatauxzoon, what life stages of the organism are found within these cells?

Answer 1

Cats
Macrophages (shizonts)
RBCs(merozoite)

Question 2

How is cyauxzoonosis different in the bobcat and panther as compared to domestic cats, what do we know of disease course in other exotic felids (lions, tigers)?

Answer 2

Bobcat and FL panther do not get sick

Exotic felids - variable susceptibility

Question 3

How has cyauxzoonosis changed over time in the domestic cat in terms of the types of presentation and clinical course of the disease? Can chronic carrier cats act as reservoir hosts?

Answer 3

Initially, domestic cats would get very sick and die

Now, drug therapies are more effective and cats are recovering from this disease

Yes

Question 4

What hematologic abnormalities and clinical signs might you see with cyauxzoonosis? How is anemia with this agent different than that seen with Mycoplasma infection in the cat? What life stage is responsible for the clinical signs?

Answer 4

Anemia (non-regenerative)
Thrombocytopenia
Leukopenia
Hyperbilirubinemia
ELE
Abnormal coag

Anemia is non-regenerative and not due to hemolysis

Infected macrophages clog liver, spleen, etc.

Question 5

Be able to diagnose Cytauxzoon on a blood smear, and differentiate this agent from other erythrocyte pathogens of the cat based upon morphology and disease manifestations.

Answer 5

Big, shizont laiden macrophages

Question 6

What is the treatment and prevention strategy for this cytauxzoonosis? What is a limitation of PCR in diagnosis of this disease?

Answer 6

Atovaquone + azithromycin

Acarides

Tick prevention

PCR takes too long when you can diagnose this on a blood smear

Question 7

Which species of Babesia are present in the United States? Of these which are the most clinically relevant? How are the two most clinically relevant species different in terms of morphology? What cell type(s) does the agent infect in mammals?

Answer 7

B. Vogeli, B. Coco, B. Gibsoni, B. Conradae, M. Microti

Large forms (B. vogeli) - tick transmission

Small forms (B. Gibsoni)- dog fights, bites

RBCs

Question 8

Be familiar with mode of transmission, disease manifestations and severity, and any breed associations related to the most clinically relevant strains of Babesiosis in the United States.

Answer 8

Greyhounds- large form (B. Vogeli)

Pitbulls- small form (B. Gibonsi)

Question 9

How do you diagnose babesiosis? What diagnostic gives you the most information? How do you treat this disease?

Answer 9

Dx: microscopy (ear prick seems to yield more organisms), Serology: Babesia spp., PCR: Genus and species **

Tx: 
Large forms (vogeli)- imidocarb diproprionate 
Small forms (gibsoni)- atovaquone + azithromycin

Question 10

Be able to diagnose Babesia infection using a blood smear, and differentiate this agent from other erythrocyte pathogens based upon morphology and disease manifestations.

Answer 10

.

Question 11

What species of Hepatozoon can be found within dogs in the United States? How is disease different between the two species of Hepatozoon discussed (clinical presentation, tissues of replication). What are some unique features of H. americanum infection that you may see on labwork or diagnostic imaging?

Answer 11

H. Americanum: fever, lethargy, cachexia, lameness, muscle pain, ocular d/c, Marked neutrophilia with low bands, periosteal rxn, encyst in muscle, low parasitemia

H. Canis: do not encyst in muscle, go to liver and spleen, mild clinical signs, high paraitemia

Question 12

How is hepatozoonosis diagnosed and treated? Be familiar with the limitations of various diagnostics.

Answer 12

H. Canis: inclusions in RBCs; imidocarb

H. Americanum: buffy coat examination, muscle biopsy; TMS, clindamycin, primethamine, decoquinate

Question 13

Be able to diagnose Hepatozoon infection using a blood smear, and differentiate this agent from other erythrocyte pathogens based upon morphology and disease manifestations.

Answer 13

.

Question 14

Where does Rangelosis occur in the world? What cell types could you find these protozoal organisms within? What sort of clinical signs are characteristic of this disease?

Answer 14

Brazil

RBCs, WBCs, extracellularly

Bleeding (bloody ear)

Question 15

What infective Mycoplasma species are relevant to the cat? To the dog? Which species of Mycoplasma have been identified on feline blood smears? Which species in the cat is the most pathogenic? How does transmission generally occur?

Answer 15

Cat: haemofelis (most severe disease, largest), haemominutum, turicensis (never seen on blood film)

Dog: haemocanis, candidatus M. Hematoparvum

Transmission: arthropod borne, flea

Question 16

What are the clinical signs and laboratory findings you may see with Mycoplasmosis in the cat? What are possible risk factors for disease in the cat? How are clinical disease and risk factors different than with Cytauxzoonosis?

Answer 16

Anemia (regenerative), icterus, auto-agglutination

Risk factors: young cats, outdoor access, retroviral +, male

Question 17

What are risk factors for development of mycoplasmosis in dogs?

Answer 17

Splenectomized

Immunosupressed

Question 18

How can diagnosis of mycoplasmosis be made? How will you submit samples to a lab for microscopic evaluation?

Answer 18

Blood smear

Need to look at smear right after it is made!

Question 19

How is mycoplasmosis treated? Does treatment reliably clear a carrier state?

Answer 19

tetracyclines, fluroquinolones

No

Question 20

Be able to diagnose Mycoplasma infection using a blood smear, and differentiate this agent from other erythrocyte pathogens based upon morphology and disease manifestations.

Answer 20

.

Question 21

What agents are responsible for monocytic Ehrlichiosis and what small animal species is more often affected?

Answer 21

E. Canis and E. Chaffeensis

Dogs

Question 22

What agents are responsible for granulocytic rickettsial infection? What blood work findings and clinical presentations might you see with these agents? How do you diagnose these agents and what are the limitations of available diagnostics? How do you treat these agents?

Answer 22

E. Ewingii and A. Phagoctophilum

Non-specific CS, thrombocytopenia, Neutrophilic polyarthropathy

Dx: serologic tests and PCR

Tx: doxycycline

Question 23

What agent is responsible for thrombocytic anaplasmosis? What blood work findings and clinical presentations might you see with this agent? How do you diagnose this agent and what are the limitations of available diagnostics? How do you treat this agent?

Answer 23

Anaplasma platys

Thrombocytopenia

CS: bleeding

Dx: PCR

Tx: doxycycline

Question 24

Be able to diagnose the Rickettsial infections covered in lecture using a blood smear, and differentiate this agent from other erythrocyte pathogens based upon morphology and disease manifestations.

Answer 24

.

Question 25

Be able to correctly identify (genus and species if possible) the organisms discussed if presented with a photomicrograph of a small animal blood film.

Answer 25

.

Question 26

What blood work findings and clinical presentations are the same for E. Canis and E. Chaffeensis? What are some lab work findings and clinical presentations that are unique to E. canis?

Answer 26

Same:
CS- fever, anorexia, lethargy, malaise, bleeding tendencies, uveitis

Lab- thrombocytopenia, anemia

Unique to E. Canis:
Hyperglobulinemia, plasmacytosis, lymphocytosis

Question 27

How do you diagnose monocytic erlichiosis and what are the limitations of available diagnostics? How do you treat these agents?

Answer 27

IFA and PCR

Doxycycline