5.13 Obligate Intracellular Bacteria

Question 1

what are the 2 intracellular orders

Answer 1

Rickettsiales and Chlamydiales

Question 2

what is the shape and staining properties of Rickettsiales and Chlamydia

Answer 2

Gram-negative coccobacilli; stain with Wright or Giemsa

Question 3

how do we diagnose Rickettsiales or Chlamydia spp.

Answer 3

direct stain, PCR, serology, growth in cells

Question 4

what are the 2 families of Rickettsiales

Answer 4

Rickettsiaceae and Anaplasmataceae

Question 5

what is the chlamydiales family

Answer 5

Chlamydiaceae

Question 6

what are the genus of Rickettsiaceae (1) and Anaplasmataceae (3)

Answer 6

Rickettsiaceae: Rickettsia
Anaplasmataceae: Neorickettsia, Anaplasam, Erlichia

Question 7

what are the genus of Chlamydiaceae (2)

Answer 7

Chlamydia and Chlamydophila

Question 8

Anaplasmataceae (Neorickettsia, Anaplasma and Erlichia) are parasites of what cells and what host type

Answer 8

hematopoietic cells; vertebrate hosts

Question 9

Neorickettsia is transmitted by _________ whereas Erlichia and Anaplasma are transmitted by

Answer 9

trematode; ticks

Question 10

A. phagocytophilum infects what cells

Answer 10

neutrophils

Question 11

Anaplasma phagocytophilum is the same as Borrelia burgdoferi because ________ and different because __________

Answer 11

transmitted by Ixodes and maintained in small mammals; is not maintained in birds

Question 12

what does Anaplasma phagocytophilum cause in dogs

Answer 12

neutropenia, thrombocytopenia, mm pain, necrotizing vasculitis

Question 13

what does Anaplasma phagocytophilum cause in horses

Answer 13

DIC, limb edema, jaundice

Question 14

what does Anaplasma phagocytophilum cause in ruminants

Answer 14

no illness to subclinical disease

Question 15

what does Anaplasma phagocytophilum cause in people

Answer 15

granulocytic erlychiosis

Question 16

what can we use to diagnose Anaplasma phagocytophilum

Answer 16

direct demo in buffy coat, PCR, SNAP test

Question 17

how do we treat and control Anaplasma phagocytophilum

Answer 17

treat: tetracycline
control: tick control (same as lyme disease mitigation)

Question 18

what is the vector for Ehrlichia spp.

Answer 18

ticks

Question 19

what cells does Ehrlichia spp. infect

Answer 19

hematopoietic cells and endothelial cells

Question 20

what is the source of Ehrlichia infections

Answer 20

rodents, canids or ruminants that are persistently infected

Question 21

what are the 3 manifestations of Ehrlichia canis infection

Answer 21

1) acute infection
2) persistent subclinical infection
3) severe, immune-mediated chronic disease

Question 22

how do we treat Ehrlichia canis

Answer 22

tetracycline

Question 23

describe the outcomes of Ehrlichia canis infection:
- acute
- persistent subclinical
- chronic, severe immune-mediated

Answer 23

acute: fever, mild anemia, thrombocytopenia, lymphadenopathy, vasculitis

persistent subclinical: mild anemia, fever, thrombocytopenia

chronic, severe immune-mediated: bleeding, epistaxis, vasculitis, weight loss, secondary infections

Question 24

where is Ehrlichia canis more present

Answer 24

Southern USA (since more brown dog ticks -> Rhipencephalus sanguineus)

Question 25

what causes canine granulocytic erlichiosis, which is spread by Ixodes scapularis, presents like A. phagocytophilum and is often concurrent with A. phagocytophilum and B. burgdoferi

Answer 25

Ehrclichia ewingii and Ehrlichia chaffeensis

Question 26

what cells does Neorickettsia infect

Answer 26

monocytes and macrophages

Question 27

what is the vector for Neorickettsia spp.

Answer 27

trematode (flukes)

Question 28

what causes salmon poisoning in dogs

Answer 28

Neorickettsia helminthoeca; an intestinal fluke of salmon containing the pathogen is consumed by dogs

Question 29

what is the causative agent of Potomac Horse Fever

Answer 29

Neorickettsia risticii

Question 30

how is N. risticii (Potomac Horse Fever) spread and

Answer 30

trematodes in bats (final host), aquatic snails (first intermediate host) and aquatic insects (second intermediate host) horses drink water infested with the aquatic insects (ex. mayflies, caddis flies)

Question 31

what are clinical signs of Potomac Horse Fever caused by Neorickettsia risticii

Answer 31

- fever - anorexia - leukopenia - laminitis - severe diarrhea

Question 32

why does Neorickettsia risticii cause diarrhea

Answer 32

the pathogen infects macrophages in the colon glandular epithelium (as well as in the intestinal lamina propria and monocytes in blood)

Question 33

how do we diagnose Potomac Horse Fever (N. risticii)

Answer 33

Buffy coat PCR

Question 34

how do we treat (2) and control (1) Potomac Horse Fever (N. risticii)

Answer 34

vaccination (not 100% due to antigenic variants) and tetracycline; control flies (ex. keep lights low)

Question 35

what cells do Chlamydia/Chlamydophila infect)

Answer 35

epithelial cells

Question 36

how is Chlamydia/Chlamydophila spread

Answer 36

in dried feces; typically animal-animal contact

Question 37

what are the 2 stages of Chlamydia/Chlamydophila's life cycle? explain in detail

Answer 37

Elementary bodies (EB) and Reticulate bodies (RB): EB: Extracellular stage including attachment and entry into the cell, replication and cell death RB: Intracellular stage from cell death to dissemination into a new host cell

Question 38

what is the agent of Psittacosis

Answer 38

Chlamydophila psittaci

Question 39

what does C. psittaci cause

Answer 39

systemic infection: conjunctivitis, hepatomegaly, splenomegaly, bronchopneumonia, bronchiolitis, fibrinous polyserositis

Question 40

what is the pathogenesis of Psittacosis

Answer 40

EBs are shed by carriers (feces) or infected birds (secretions) -> inhaled -> replicates in epithelial and phagocytic cells -> multi-organ infection

Question 41

how do we diagnose C. psittaci

Answer 41

PCR, serology, Giemsa stain

Question 42

how do we control and treat C. psittaci

Answer 42

Treat: tetracycline Prevent: isolate and quarantine imported birds

Question 43

what does Chlamydophila abortus cause and in what species?

Answer 43

- enzootic abortion in sheep/goats - pneumonia - infertility - conjunctivitis - arthritis (other signs besides abortion occur in cattle as well)

Question 44

how do we diagnose Chlamydophila abortus

Answer 44

Giemsa staining, egg isolation, PCR

Question 45

how do we treat and control Chlamydophila abortus

Answer 45

tetracyclines, vaccination (in sheep)

Question 46

what is the agent of Q fever

Answer 46

Coxiella burnetii

Question 47

Coxiella burnetii is a "_______ ________ _________ " pathogen

Answer 47

broad host range (endemic in ruminants, causes disease in humans, subclinical in cats)

Question 48

what makes Coxiella burnetii highly persistent

Answer 48

endospore-like form

Question 49

in what animals will Coxiella burnetii persist subclinically and what is the consequence

Answer 49

in carrier females; released in huge amounts at parturition

Question 50

how is Coxiella burnetii spread

Answer 50

usually by inhalation but also ingestion or tick-borne; present in milk, birth fluids, urine and feces

Question 51

what is important for Coxiella burnetii transmission

Answer 51

dust

Question 52

how do we diagnose Coxiella burnetii

Answer 52

PCR, serology, direct-demonstration

Question 53

how do we treat and control Coxiella burnetii

Answer 53

treat with tetracyclines; control with hygeine, education, early diagnosis, vaccination