|
|
(11 intermediate revisions by 2 users not shown) |
Line 1: |
Line 1: |
− | ===Overview=== | + | {{frontpage |
| + | |pagetitle =Chlamydophila species |
| + | |pagebody = |
| + | |contenttitle =Content |
| + | |contentbody =<big><b> |
| + | <categorytree mode=pages>Chlamydophila species</categorytree> |
| + | </b></big> |
| + | |logo =bugs-logo copy.png |
| + | }} |
| | | |
− | *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
| |
| | | |
− | | + | [[Category:Bacterial Organisms]] |
− | ===Characteristics===
| + | [[Category:Gram_negative_bacteria]] |
− | | |
− | *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''===
| |
− | | |
− | *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
| |
− | | |
− | | |
− | ===''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
| |
− | | |
− | | |
− | *May cause [[Joints Inflammatory - Pathology#In Sheep|arthritis in sheep]] and [[Joints Inflammatory - Pathology#In Cattle|arthritis in cattle]]
| |
− | [[Category:Bacteria]] | |