Difference between revisions of "Chlamydia and Chlamydophila species"

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#REDIRECT[[:Category:Chlamydophila species]]
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<br>
 +
===Overview===
 +
 
 +
*Host adapted and non-host adapted species varying in virulence for different hosts
 +
*Species cause specific diseases in particular hosts
 +
*Repsiratory, 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''===
 +
 
 +
*Causes notifiable psittacosis in birds
 +
*Epidemiology:
 +
**Many wild and domestic birds susceptible
 +
**Organisms present in respiratory secretions and faeces of infected birds
 +
**Infection via inhalation or ingestion
 +
**Subclinical infection common
 +
**Intermittent shedding for prolonged periods
 +
**Stress precipitates disease outbreaks
 +
*Clinical signs:
 +
**Generalised infection affecting intestinal and respiratory tracts
 +
**Up to 10 day incubation period
 +
**Loss of condtion, oculonasal discahrge, diarrhoea and respiratory distress depending on strain
 +
**Hepatomegaly, airsacculitis and peritonitis
 +
*Diagnosis: stained smears, immunohistochemistry, ELISA, PCR, isolation, antibody detection by ELISA and complement fixation
 +
*Treatment: tetracyclines for several weeks
 +
*Control: quaranteen imported birds and give tetracyclines; good husbandry
 +
*Involved in [[Nasal Cavity Inflammatory - Pathology#In Cats|feline rhinotracheitis]] together with [[Herpesviridae|herpes virus 1]]
 +
*Zoonotic by aerosol infection - can cause systemic disease with pneumonia, meningitis or meningoencephalitis
 +
 
 +
 
 +
===''Chlamydophila abortus''===
 +
 
 +
*Ovine enzootic abortion
 +
*Especially in intensive systems
 +
*Ewe lambs may acquire infection at birth and abort in their first pregnancy
 +
*Pathogenesis:
 +
**Infection via ingestion or inhalation causes a bacteraemia
 +
**Bacteria localise in placenta and cause placentitis, leading to late abortion or premature weak lambs
 +
**Necrosis of cotyledons and oedema of adjacent tissue, as well as dirty pink uterine discharge
 +
**Aborted lambs well preserved
 +
**Large numbers of chlamydiae shed in placenta and uterine discharges; survive in environment for several days
 +
**Abortion rates may reach 30% in susceptible flock
 +
**Ewes infected late in pregnancy may not abort, but may abort during the next pregnancy
 +
**No other clinical signs in aborting ewes
 +
**Fertility not impaired
 +
*Transmission:
 +
**Survival of elementary bodies in faeces and wild birds are a source of infection from one lambing season to the next
 +
**Ewes may be carriers for several years
 +
**Venereal transmission from infected rams
 +
**Some immunity develops after infection, protecting ewes from subsequent disease
 +
*Vaccination:
 +
**Live attenuated vaccines prior to breeding or inactivated vaccines during pregnancy
 +
**Vaccines prevent infection but will not clear infection from persistently-infected animals
 +
**Vaccination of ewe lambs prior to breeding
 +
*Treatment: long-acting oxytetracyclines during an outbreak to protect in-contact pregnant ewes
 +
*Control: isolate aborted ewes; destroy placentas, thorough cleaning
 +
*Also abortion in cattle, goats and pigs
 +
*Serious infection in pregnant women
 +
 
 +
 
 +
===''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-Neelson) 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 embyonated 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]]

Revision as of 09:40, 25 September 2008

 This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing.


Infectious agents and parasitesWikiBugs Banner.png
BACTERIA



Overview

  • Host adapted and non-host adapted species varying in virulence for different hosts
  • Species cause specific diseases in particular hosts
  • Repsiratory, 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

  • Causes notifiable psittacosis in birds
  • Epidemiology:
    • Many wild and domestic birds susceptible
    • Organisms present in respiratory secretions and faeces of infected birds
    • Infection via inhalation or ingestion
    • Subclinical infection common
    • Intermittent shedding for prolonged periods
    • Stress precipitates disease outbreaks
  • Clinical signs:
    • Generalised infection affecting intestinal and respiratory tracts
    • Up to 10 day incubation period
    • Loss of condtion, oculonasal discahrge, diarrhoea and respiratory distress depending on strain
    • Hepatomegaly, airsacculitis and peritonitis
  • Diagnosis: stained smears, immunohistochemistry, ELISA, PCR, isolation, antibody detection by ELISA and complement fixation
  • Treatment: tetracyclines for several weeks
  • Control: quaranteen imported birds and give tetracyclines; good husbandry
  • Involved in feline rhinotracheitis together with herpes virus 1
  • Zoonotic by aerosol infection - can cause systemic disease with pneumonia, meningitis or meningoencephalitis


Chlamydophila abortus

  • Ovine enzootic abortion
  • Especially in intensive systems
  • Ewe lambs may acquire infection at birth and abort in their first pregnancy
  • Pathogenesis:
    • Infection via ingestion or inhalation causes a bacteraemia
    • Bacteria localise in placenta and cause placentitis, leading to late abortion or premature weak lambs
    • Necrosis of cotyledons and oedema of adjacent tissue, as well as dirty pink uterine discharge
    • Aborted lambs well preserved
    • Large numbers of chlamydiae shed in placenta and uterine discharges; survive in environment for several days
    • Abortion rates may reach 30% in susceptible flock
    • Ewes infected late in pregnancy may not abort, but may abort during the next pregnancy
    • No other clinical signs in aborting ewes
    • Fertility not impaired
  • Transmission:
    • Survival of elementary bodies in faeces and wild birds are a source of infection from one lambing season to the next
    • Ewes may be carriers for several years
    • Venereal transmission from infected rams
    • Some immunity develops after infection, protecting ewes from subsequent disease
  • Vaccination:
    • Live attenuated vaccines prior to breeding or inactivated vaccines during pregnancy
    • Vaccines prevent infection but will not clear infection from persistently-infected animals
    • Vaccination of ewe lambs prior to breeding
  • Treatment: long-acting oxytetracyclines during an outbreak to protect in-contact pregnant ewes
  • Control: isolate aborted ewes; destroy placentas, thorough cleaning
  • Also abortion in cattle, goats and pigs
  • Serious infection in pregnant women


Chlamydophila felis

  • Host adapted species in cats
  • 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-Neelson) 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 embyonated eggs and McCoy cells as well as animal tissues
  • PCR to detect chlamydial DNA
  • Serological tests: complement fixation, ELISA, indirect immunofluorescence


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