Obligate Intracellular Bacteria Flashcards
Obligate intracellular bacteria of Veterinary Importance:
Invade host cells to survive for own benefit. Similar to a virus.
- Chlamydia
- Coxiella
- Anaplasma
- Lawsonia
- Rickettsia
- Ehrlichia
GRAM NEGATIVE BACTERIA
Small, AT rich genomes.
Chlamydia Infection Cycle:
Infective form
Adherance to Cell Membrane
Entry by Endocytosis
Prevention of phagosome-lysosome fusion
Replicative form (not infective)
Divison- formation of Inclusion body
Differentation into “infective form”
Host cell lysis
Exit from Infected cell
Infective form infects new host.
Chlamydia Developmental phases:
- EB (Elementary Body)
Infective form, spore like, tolerant of environmental stress.
- RB (Reticulate Body)
**Non-infective, replicative stage, divides by Binary fission. **
Pathogenic Mechanisms of Chlamydiae:
- Cytophathic effect: Intereferes with metabolism causes cytolysis where EB’s released by cell lysis.
- PAMP (modulin) activity- triggers innate inflammatory response inducing release of cytokines.
- Actue Inflammation- Neutroophils, macrophages.
- Delayed Type Hypersensitity: cell-mediated immune response. (uncontrolled continuted inflammatory damage)
- Secondary Immunopathology- primary expsure may not be significant pathogology. Secondary exposure is more severe.
Chlamydophila abortus:
What disease does this cause?
Comment on the Immune response to this pathogen.
Enzootic Abortion of Ewes (EAE)
Ovine Enzootic Abortion (OEA)
Primary exposure is more severe than secondary.
Primary exposure: 30% abort- productive infection
Secondary exposure: 5% abort- animals reinfected but pathology is significantly lower.
What does this indicate?
Indicateds exposure can result in effective Immune response since the secondary exposure is less severe!!!!!
C. abortus- OEA Infection cycle:
Ingestion/ inhalation
Localization to tonils/ lymph nodes
Dissemination
Latent, persistant, or intermittent infection
Placentitis
Fetal infection
Abortion, stillbirth, weak lambs, subclinically infected lambs.
C. abortus- Treatment/ control
Zoonosis?
Antibiotics- tetracyclines
Respiratory & abortion Zoonotic.
Feline Chlaymydiosis:
What clinical signs does this cause?
Mucopurulent conjuctivitis & Rhinitis
Highly infectious
ZOONOSIS.
Avian Chlamydiosis:
What disease does it cause?
Comment on its effects in Adult birds and Young birds.
Causes Psittacosis, Ornithosis disease (Parrot fever)
- Adult Birds: asymptomatic, persistant
- Young/ Stressed:
- Acute, generalized disease
- Multisystemic inflammation
-Discharges, dperession, inappetance, diarrhea
- 90% mortality
- ZOONOSIS
What strain of chlamydia causes the most Zoonotic infections?
Avian Chlamydia
Fevers
Chills
Headache
Muscle aches
dry cough
Anaplasmosis & Ehrlichiosis:
Main diseases they cause?
Arthropod Borne
Geographically restricted to where arthropods found.
- A. phagocytophilum- Tick Borne Fever –> infects neutrophils.
- E. canis- Canine Ehrlichiosis- Infects monocytes
Tick Borne Fever
Anaplasma phagocytophilum
Affects Ruminants
Reproduces in tick Hemolymph
Inoculation by tick mate
Infection of PMN (neutrophils)
Pathogensis of Anaplasma phagocytophilum TBF:
Infection of PMN
Cytokine release of by neutrophils
Neutropenia occurs
Neutropenia causes:
- Fever, aborton, Decreased milk yields, decreased wt. gain
- immunocompromisation leading to secondary infections
Coxiella burnetti- Q fever
Asymptomatic in ruminants (occasionally can cause abortion storms)
Excreted in urine, feces, milk, placenta
Inhalation by human (Zoonotic)
Infects respiratory epithelium, endothelium, & phagocytosis.
Influenza-like syndrome (pneumonia, endocarditis)
SCHEDULE 5 ZOONOSIS.
Porcine Proliferative Enteropathy: PE; ileitis
What does it mean economically?
what are the clinical signs?
Reduced feed conversion
Reduced/ variable weight gain
Variable slaughter weight.
Low slaugther weight
Low value
Will show Hemorrhagic diarrhea, diarrhea, fatalities seldom occur.
