E2 Order Rickettsiales Flashcards Preview

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Flashcards in E2 Order Rickettsiales Deck (70)
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1

Pathogen
Disease
Host
Mechanism
Immunity
Culture
Notes

???

2

What tissue are Rickettsiales (order) of bacteria tropic for?

Vascular endothelium or leukocytes

3

What is unique about Rickettsiales (order) bacteria transmission?

Arthropod vectors

4

What is the gram reaction & appearance of Rickettsiales (order) bacteria?

Gram-negative
Pleomorphic (variable shape)

5

What type of disease do Rickettsiales (order) bacteria cause?

Multisystemic disease

6

What is unique about the Rickettsiales (order) bacteria location in the animal?

Intracellular pathogen
(vascular endothelium or leukocytes)

7

Why is it difficult to culture or treat Rickettsia (genus) bacteria?

They are obligate intracellular pathogens

8

What cell types do Rickettsia (genus) bacteria target?

Reticuloendothelial system cells
(endothelial cells & monocytes)

9

What animals are incidental hosts of Rickettsia rickettsii? Why?

Humans & dogs
They do not have enough parasitemia to infect ticks (dogs may be able to cause infection in ticks)

10

What animals are normal hosts for Rickettsia rickettsii?

Small mammals

11

What is the arthropod vector for Rickettsia rickettsii?

Ticks

12

What disease does Rickettsia rickettsii cause?

Rocky mountain spotted fever (RMSF)

13

What is rocky mountain spotted fever (RMSF)?

Acute febrile infectious vasculitis

14

How long do ticks need to feed to transmit Rickettsia rickettsii?

6-24 hrs

15

What causes the spots in rocky mountain spotted fever?

Endothelial cell damage causes petechia

16

When do clinical signs appear from Rickettsia rickettsii in dogs?

2-14 days after infection

17

Do dogs require treatment for Rickettsia rickettsii infection?

Not usually
Most dogs eliminate the infection naturally

18

What can happen in dogs infected with Rickettsia rickettsii?

Vascular leakage
Edema
Hypotension
Shock

19

What is the best way to diagnose Rickettsia rickettsii infection in dogs (2 methods)?

1. Visualization of the organism on blood smears
2. Paired serum samples (antibodies)
= single HIGH IgG titer

20

What is the most consistent lab finding in Rickettsia rickettsii infection?

1. Thrombocytopenia
2. Fever 5 days after infection

21

How is Rickettsia rickettsii infection usually diagnosed?

Retrospectively
Dogs gets better with antibiotic treatment

22

Is there a vaccine against Rickettsia rickettsii infection?

No

23

Is there any evidence of Rickettsia rickettsii transmission from dogs to humans?

No

24

What is another family in the order Rickettsiales that is of veterinary importance?

Anaplasmataceae

25

What are some important genera in the family Anaplasmataceae?

1. Anaplasma
2. Ehrlichia
3. Neorickettsia

26

What is the gram reaction, tropism and transmission of bacteria in the family Anaplasmataceae?

1. Gram-negative
2. Obligate parasites of erythrocytes (RBCs) & leukocytes
3. Arthropod vectors = ticks & biting flies

27

What is the most pathogenic species of Anaplasma?

Anaplasma marginale

28

What does Anaplasma marginale infection look like microscopically?

Dense inclusion bodies in RBCs

29

Is Anaplasma marginale a reportable disease?

Yes!

30

What animals can be infected with Anaplasma marginale?

Ruminants
Important disease of cattle in Gulf Coast region