Difference between revisions of "Category:Chlamydophila species"

From WikiVet English
Jump to navigation Jump to search
Line 48: Line 48:
  
  
===''Chlamydophila felis''===
+
===''[[Chlamydophila felis]]''===
 +
 
  
*Host adapted species in cats
 
*[[Respiratory Bacterial Infections - Pathology#Feline Chlamydiosis|Feline chlamydiosis]]
 
*Feline conjunctivitis, rhinitis and rarely interstitial pneumonia
 
*Epidemiology
 
**Up to 10% cats infected
 
**Infection via contact with conjunctival or nasal secretions
 
**Infection may persist with prolonged shedding and clinical relapses
 
**Stress of parturition and lactation may cause shedding of organisms leading to transmission to offspring
 
*Clinical signs:
 
**Incubation period 5 days
 
**Conjunctival congestion, clear ocular discharge, blepharospasm
 
**May have sneezing and nasal discharge
 
**Resolves within a few weeks, or causes persistent infection
 
*Diagnosis:
 
**Intracytoplasmic inclusions in stained conjunctival smears
 
**Antigen detection in ocular/nasal secretions - ELISA, PCR, Kosters, fluorescent antibody test
 
*Modified live vaccines reduce clinical signs but do not prevent infection or shedding
 
  
  
Line 99: Line 83:
 
*May cause [[Joints Inflammatory - Pathology#In Sheep|arthritis in sheep]] and [[Joints Inflammatory - Pathology#In Cattle|arthritis in cattle]]
 
*May cause [[Joints Inflammatory - Pathology#In Sheep|arthritis in sheep]] and [[Joints Inflammatory - Pathology#In Cattle|arthritis in cattle]]
 
[[Category:Bacteria]]
 
[[Category:Bacteria]]
 +
[[Category:Gram_negative_bacteria]]

Revision as of 10:21, 12 May 2010

Overview

  • Host adapted and non-host adapted species varying in virulence for different hosts
  • Species cause specific diseases in particular hosts
  • Respiratory, enteric, pleural and reproductive diseases in animals and humans
  • Conjunctivitis, arthritis, abortion, urethritis, enteritis, pneumonia, encephalomyelitis
  • Manifestation varies from subclinical to severe systemic infections
  • Intestinal infections often subclinical and persistent
  • Human infections usualy acquired from infected birds, causing psittacosis or ornithosis, causing respiratory infections


Characteristics

  • Obligate intracellular bacteria
  • Gram negative bacteria with outer membrane, LPS, ribosomes, DNA and RNA
  • Peptidoglycan cell wall resistant to lysozyme
  • Only grow in presence of living eukaryotic cells
  • Unable to synthesis ATP therefore require intermediates from host cells
  • Not stained by Gram stain
  • Two morphological forms
    • Elementary body, the infective extracellular form, which is small, metabolically inert and osmotically stable; surrounded by cytoplasmic membrane, outer membrane with LPS, but no peptidoglycan
    • Retiuculate body: larger, metabolically active, osmotically fragile
  • Elementary body survives in the environment for several days


Pathogenesis and pathogenicity

  • Elementary body enters host epithelial cells by receptor-mediated endocytosis
  • Transformation into larger reticulate body within endosome; known as an inclusion
  • Reticulate body divides by binary fission to form many new chlamydia cells
  • Reticulate bodies mature and condense to form elementary bodies
  • Elementary bodies released from dying host cells after about 72 hours to infect other cells
  • Persistent infections can occur if replication delayed by environmental conditions such as presence of interferon gamma
  • Many infections subclinical due to intracellular existence of chlamydia preventing inflammatory reactions
  • Chronic infections may fail to induce an immune response, or may repeatedly stimulate the immune system, causing a delayed hypersensitivity reaction and tissue damage
  • Prolonged faecal shedding of organisms
  • Clinical infections occur in non-natural host species
  • CLinical signs depend on route of infection and degree of exposure


Chlamydophila psittaci

Chlamydophila abortus

Chlamydophila felis

Chlamydophila pecorum

  • Common inapparent intestinal infection of cattle
  • Conjunctivitis and arthritis
  • Sporadic bovine encephalomyelitis:
    • Usually in cattle under 3 years
    • Fever, incoordination, depression, excessive salivation, diarrhoea
    • Recumbency and opisthotonos before death
    • Up to 50% mortality
    • Vacular damage in brain
    • Serofibrinious peritonitis
    • Treat with high doses tetracyclines and tylosin


Diagnosis

  • Direct microscopy of smears and tissues e.g. organs from aborted foetuses, liver/spleen from avian cases
  • Kosters (modified Ziehl-Neelsen) stain of placental smears shows small red rods
  • Blue inclusions in cytoplasm of Giemsa-stained cells
  • Methylene blue stain with darkfield microscopy
  • Fluorescent antibody stain
  • Antigen detection kits for diagnosis from swabs
  • ELISA to detect Chlamydophila LPS
  • Isolation in embryonated eggs and McCoy cells as well as animal tissues
  • PCR to detect chlamydial DNA
  • Serological tests: complement fixation, ELISA, indirect immunofluorescence


Pages in category "Chlamydophila species"

The following 5 pages are in this category, out of 5 total.