Difference between revisions of "Chlamydia and 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> | ||
| + | |||
| + | |||
| + | ''Chlamydophila psittaci'' involved in [[Nasal cavity - inflammatory#In Cats|feline rhinotracheitis]] together with [[Herpesviridae|herpes virus 1]] C.psittaci more frequently infects the conjunctival epithelium -> chronic conjunctivitis, see [[Bacterial infections#Feline Chlamydiosis|feline chlamydiosis]] | ||
| + | |||
| + | *May cause [[Joints - inflammatory#In Sheep|arthritis in sheep]] and [[Joints - inflammatory#In Cattle|arthritis in cattle]] | ||
| + | |||
| + | ===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 ornthosis, 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 | ||
| + | |||
| + | |||
| + | ===''Chlamydophila abortus''=== | ||
| + | |||
| + | *Ovine enzootic abortion | ||
| + | *Especially in intensive systems | ||
| + | *Ewe lambs may acquire infection at birth and abort in their first pregnancy | ||
| + | *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 | ||
| + | *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 | ||
| + | *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 interstitial pneumonia and conjunctivitis | ||
| + | *Diagnosis by antigen detection in ocular/nasal secretions - ELISA, PCR, Kosters, fluorescent antibody test | ||
| + | *Vaccine | ||
| + | |||
| + | |||
| + | |||
| + | |||
| + | ===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 | ||
Revision as of 10:39, 18 May 2008
Chlamydophila psittaci involved in feline rhinotracheitis together with herpes virus 1 C.psittaci more frequently infects the conjunctival epithelium -> chronic conjunctivitis, see feline chlamydiosis
- May cause arthritis in sheep and arthritis in cattle
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 ornthosis, 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
Chlamydophila abortus
- Ovine enzootic abortion
- Especially in intensive systems
- Ewe lambs may acquire infection at birth and abort in their first pregnancy
- 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
- 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
- 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 interstitial pneumonia and conjunctivitis
- Diagnosis by antigen detection in ocular/nasal secretions - ELISA, PCR, Kosters, fluorescent antibody test
- Vaccine
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