Obligate Intracellular Bacteria

Question 1

Intracellular bac

Answer 1

gram neg
small
AT- rich genomes, potentially allowing more stability

Question 2

Detection of intracellular bacteria

Answer 2

Co-culture with eukaryotic cells
Microscopy- non-specific staining immunohistochemistry
Immune responses- antibody or CMI
Genome detection-PCR

Question 3

Chlamydia spp

Answer 3

Diverse group, widely distributed

+ developmental forms, zoonosis, targeting epithelium and mac

Includes infectious and replicative form

Question 4

Chlamydia elementary body

Answer 4

Infective stage
spore like, small and dense
Tolerant of environmental stress

Question 5

Reticulate body

Answer 5

non-infective
Replicative stage
Binary fission

Question 6

Chlamydophila abortus

Answer 6

Enzootic Abortion of Ewes (EAE)/Ovine Enzootic Abortion (OEA)

Continually present in UK flock, at 1st exposure ~30% abort, at > or =2 ~5% abort which seems indicative of protective immune response

Question 7

OEA transmission

Answer 7

Ingestion/inhalation ->localization to tonsils/LN -> dissemination -> latent, persistent or intermittent infection (dont see symptoms until late in pregnancy) -> placentitis ->fetal infection -> abortion, stillbirth, weak lambs, subclinically infected lambs

Question 8

OEA treatment and control

Answer 8

Antibiotics- tetracyclines
Closed flocks/OEA-free accreditation
Vac- control disease, but wont prevent infection

Zoonosis- respiratory and abortion

Question 9

Feline Chlamydiosis- Cp. felis

Answer 9

mucopurulent conjunctivitis & rhinitis highly infectious

Zoonosis

Question 10

Avian chlamydiosis- Cp. psittaci

Answer 10

Widespread in birds
Psitacosis- when disease originates in parrots
Ornithosis- when disease originates in bird other than parrot family

Acute, generalized disease
Multi-systemic inflammation (air sacs, lung, intestine,pericardium ect)
Discharges, depression, inappetence, diarrhea
Dissemination to spleen, liver and kidneys
Up to 90% mortality

Convalesent carriers- usually survive, but spread bac

Zoonosis

Question 11

Zoonotic Chlamydiosis

Answer 11

Fever, chills, headache, muscle ache, dry non- productive cough, malaise, pneumonia, endocarditis/meningitis, abortion

Majority of cases are from avian source (C. psittaci is ATCSA schedule 5), rare to get from sheep or cat

Question 12

Pathogenic mechanisms of chlamydiae

Answer 12

Cytopatic effect- interferes with metabolism cytolysis
Modulin activity- induces IFNy, IL1, IL6, TNFa
Acute inflammation- nut and mac (mixed inflammatory response)

Delayed-type hypersensitivity cell-mediated immune responses

2o immunopathology (uncontrolled immune response can cause inflammatory damage)
Intraphagocytic survival
Latency and persistence

Question 13

Anaplasmosis spp

Answer 13

arthropod born, geographically restricted

Question 14

Ehrlichia spp

Answer 14

arthropod born
geographically restricted
Causes Ehrlichoisoes

Zoonotic

Question 15

Anaplasmoses phagocytophilum

Answer 15

Tick born fever- targets neutrophil

Question 16

Ehrlichiosis canis

Answer 16

Targets canine monocyte

Question 17

Ehrlichia chaffeensis

Answer 17

Targets canine and human neutrophil

Question 18

Ehrlichia risticii

Answer 18

Potomac fever, targeting entrocyte

Question 19

Tick-borne fever

Answer 19

Tick hemolymph sustains the organism, inoculation by tick bite, leads to infection of PMN-> cytokine release, neutropaenia -> fever, abortion, decreased milk yield, decreased weight gain (all of which is non diagnostic) or immunocompromise -> 2o infection such as tick pyaemia (S. aureus), systemic pasteurellosis, louping ill, listeriosis

Persistent infection (reservoir)

Question 20

Coxiella

Answer 20

Spores
Arthropod transmission
Zoonosis
Targets epithelium and mac

Question 21

Coxiella burnetti

Answer 21

Q fever

Asymptomatic in ruminants and can lead to abortion storms

Excreted in urine, feces, milk, placenta ->inhalation by human ->infects respiratory epithelium, endothelium, and phagocytes -> influenza like syndrome, pneumonia, and endocarditis

Zoonosis (ATCSA schedule 5)

Question 22

Porcie Proliferative Enteropathy

Answer 22

Ileitis
Production disease, reduced feed conversion with reduced/variable weight gain -> lower slaughter weight/value

Highly prevalent - up to 95% seropositivity
Diarrhea is dark and slightly bloody
Haemorrhagic enteritis
Sudden death

Question 23

Pathogenesis of Porcine Proliferative Enteropathy

Answer 23

Ingestion leads to invasion of ileal crypt enterocytes, leading to epithelial hyperplasia and intestinal thickening

Question 24

Lawsonia

Answer 24

Potential zoonosis that affects epithelium

Question 25

Lawsonia intracellularis

Answer 25

obligately intracellular with many unique genes and proteins

Question 26

Controling Porcine Proliferative Enteropathy

Answer 26

Antibiotics- tylosin, tiamulin, tetracycline
Biosecurity
Vaccine- attenuated L. intracellularis strain and use as oral drench or put in water, decreases variability, and increases weight gain and productivity