Obligate Intracellular Bacteria Flashcards
Intracellular bac
gram neg
small
AT- rich genomes, potentially allowing more stability
Detection of intracellular bacteria
Co-culture with eukaryotic cells
Microscopy- non-specific staining immunohistochemistry
Immune responses- antibody or CMI
Genome detection-PCR
Chlamydia spp
Diverse group, widely distributed
+ developmental forms, zoonosis, targeting epithelium and mac
Includes infectious and replicative form
Chlamydia elementary body
Infective stage
spore like, small and dense
Tolerant of environmental stress
Reticulate body
non-infective
Replicative stage
Binary fission
Chlamydophila abortus
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
OEA transmission
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
OEA treatment and control
Antibiotics- tetracyclines
Closed flocks/OEA-free accreditation
Vac- control disease, but wont prevent infection
Zoonosis- respiratory and abortion
Feline Chlamydiosis- Cp. felis
mucopurulent conjunctivitis & rhinitis highly infectious
Zoonosis
Avian chlamydiosis- Cp. psittaci
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
Zoonotic Chlamydiosis
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
Pathogenic mechanisms of chlamydiae
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
Anaplasmosis spp
arthropod born, geographically restricted
Ehrlichia spp
arthropod born
geographically restricted
Causes Ehrlichoisoes
Zoonotic
Anaplasmoses phagocytophilum
Tick born fever- targets neutrophil
Ehrlichiosis canis
Targets canine monocyte
Ehrlichia chaffeensis
Targets canine and human neutrophil
Ehrlichia risticii
Potomac fever, targeting entrocyte
Tick-borne fever
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)
Coxiella
Spores
Arthropod transmission
Zoonosis
Targets epithelium and mac
Coxiella burnetti
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)
Porcie Proliferative Enteropathy
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
Pathogenesis of Porcine Proliferative Enteropathy
Ingestion leads to invasion of ileal crypt enterocytes, leading to epithelial hyperplasia and intestinal thickening
Lawsonia
Potential zoonosis that affects epithelium
Lawsonia intracellularis
obligately intracellular with many unique genes and proteins
Controling Porcine Proliferative Enteropathy
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
