Difference between revisions of "Chlamydia and Chlamydophila species"

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#REDIRECT[[:Category:Chlamydophila species]]
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<big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big>
 +
<big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big>
 +
 
 +
===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#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
 +
*[[Bacterial infections#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#In Sheep|arthritis in sheep]] and [[Joints - inflammatory#In Cattle|arthritis in cattle]]

Revision as of 11:15, 18 May 2008

BACK TO INFECTIOUS AGENTS AND PARASITES
BACK TO 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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