Difference between revisions of "Paramyxoviridae"

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#REDIRECT[[:Category:Paramyxoviridae]]
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<big><center>[[Viruses|'''BACK TO VIRUSES''']]</center></big>
 +
 
 +
 
 +
===Overview===
 +
 
 +
*Systemic infections - controlled by '''live monotypic vaccination'''
 +
*Respiratory infections - ''not'' controled by '''live monotypic vaccinations'''
 +
*[http://www.pitt.edu/~super1/lecture/lec3401/index.htm On line Paramyxoviridae lecture by P. Russell]
 +
 
 +
 
 +
===Classification===
 +
 
 +
*'''Paramyxovirinae'''
 +
**[[Paramyxoviridae#Bovine Parainfluenza - 3 (PI-3)| Bovine Parainfluenza 3]]
 +
**[[Paramyxoviridae#Canine Parainfluenza - 2|Canine Parainfluenza 2]]
 +
**[[Paramyxoviridae#Murine Parainfluenza - 1 (Sendai virus)|Murine Parainfluenza 1 (Sendai virus)]]
 +
**[[Paramyxoviridae#Newcastle Disease Virus (NDV)|Newcastle Disease (NDV)]] - avian paramyxovirus serotype 1
 +
**Avian Paramyxoviruses serotypes 2-9
 +
**[[Paramyxoviridae#Reptilian Paramyxoviruses|Reptilian Paramyxoviruses]]
 +
**Mumps
 +
*'''Morbilliviruses'''
 +
**[[Paramyxoviridae#Canine Distemper Virus (CDV)|Canine Distemper (CDV)]]
 +
**Rinderpest
 +
**Pest de petit ruminant (PPR)
 +
**Measels
 +
**Seal virus - phocine distemper
 +
**Dolphin Morbillivirus
 +
**[[Paramyxoviridae#Hendra Virus|Hendra virus]]
 +
**[[Paramyxoviridae#Nipah Virus|Nipah virus]]
 +
*'''Pneumovirinae'''
 +
**[[Paramyxoviridae#Bovine Respiratory Syncytial Virus (BRSV)|Bovine Respiratory Syncytial Virus (BRSV)]]
 +
**Turkey Rhinotracheitis Virus
 +
 
 +
 
 +
===Virus properties===
 +
 
 +
====Structure====
 +
 
 +
*Negative sense '''RNA''', unsegmented, single stranded
 +
**-> '''Reasortment''' and '''antigenic shift''' cannot occur
 +
*'''HN spike''' contains:
 +
**'''Haemagglutinin (H)'''- attachment protein
 +
**'''Neuraminidase (N)'''
 +
*'''Fusion''' glycoprotein (F) spike
 +
**-> Viral lipid bilayer can fuse directly with host plasma membrane
 +
***-> RNA released into cytoplasm
 +
**->Syncytium (multinucleated giant cells) in lesions and cell culture
 +
**Host antibody response to this protein is most important
 +
***Best induced by '''live attenuated vaccines'''
 +
 
 +
====Growth ''in vitro''====
 +
 
 +
*Allantoic cavity of 10-day-old eggs
 +
*Followed by '''haemagglutination'''
 +
 
 +
====''In vivo''====
 +
 
 +
*Cell tropism for upper respiratory tract epithelium
 +
**All replicate in these cells
 +
*Some replicate in the gut
 +
*Most virulent replicate in lymphoid cells and neurons ([[Paramyxoviridae#Canine Distemper Virus (CDV)|Distemper]], [[Paramyxoviridae#Newcastle Disease Virus (NDV)|NDV]])
 +
*Links to the readiness to cleave Fo and Ho precursors in different cells
 +
 
 +
====Antigenic differentiation====
 +
 
 +
*Major conserved immunodominant virus-specific antigens on [[Paramyxoviridae#Structure|F and HN]]
 +
**-> Vaccines protect against all isolates of the same virus
 +
*Minor morbillivirus-specific epitopes on [[Paramyxoviridae#Structure|F]]
 +
**Some crossprotectin between [[Paramyxoviridae#Canine Distemper Virus (CDV)|canine distemper]], measels and rinderpest
 +
*Minor variable epitopes of [[Paramyxoviridae#Structure|F, HN and '''NP''']]
 +
**Allows antigenic '''fingerprinting'''
 +
 
 +
 
 +
===Newcastle Disease Virus (NDV)===
 +
 
 +
*'''Hosts'''
 +
**Gallinaceous birds, pigeons, parrots, finches
 +
**Subclinical carriers: ducks, ostriches
 +
**Causes conjunctivitis in humans
 +
 
 +
*'''Virulence'''
 +
**Disease ranges from subclinical [[Viral infections|respiratory tract infections]] -> torticollis -> haemorrhages and death
 +
 
 +
*'''Epidemiology'''
 +
**Air-born
 +
**Direct contact of poultry
 +
 
 +
*'''Diagnosis'''
 +
**Samples of trachea and gut of 20 birds are tested in eggs
 +
**'''HI''' using anti-NDV serum (to differentiate '''HA''' caused by [[Orthomyxoviridae|avian influenza]]
 +
**Animal test: virulence of isolate tested by the speed it kills chicks
 +
**Sequencing the cleavage site of [[Paramyxoviridae#Structure|H]] gene
 +
***The more basic amino acids the more virulent the virus
 +
***Now replacing the animal test
 +
 
 +
*'''Control'''
 +
**Isolation of stock
 +
**Vaccination of chickens and racing pigeons
 +
**Surveillance of imported exotic birds
 +
**Notifiable disease
 +
**Infected premises to be culle and firebreak cull if spread
 +
 
 +
 
 +
===Reptilian Paramyxoviruses===
 +
 
 +
*Infect central nervous system and lungs
 +
*Kill particularly snakes
 +
*Healthy reptiles may be carriers
 +
*Testing by serology - '''HI test'''
 +
*Aim to keep virus free collection and prevent spread back into the wild
 +
 
 +
 
 +
===Murine Parainfluenza - 1 (Sendai virus)===
 +
 
 +
*Endemic in many mouse colonies
 +
*Most mice show no symptoms due to maternal antibodies
 +
*But minor respiratory lesions may invalidate carcinogenic or toxicological studies
 +
*Immunological studies also confused due to virus activating [[General Pathology - Antigen Recognition, Processing and Presentation#NK Receptors|NK cells]] via high circulating [[General Pathology - Innate Immunity#Interferons|IF]] 3-4 days post-infection
 +
*Control achieved by:
 +
**Purchasing specific pathogen free (SPF) mice
 +
**Kill whole colony in an outbreak -> disinfection -> formalin fumigation
 +
 
 +
 
 +
===Canine Parainfluenza - 2===
 +
 
 +
*or Parainfluenza - 5
 +
*Infects dogs
 +
*May cause mild upper respiratory infection, [[Nasal cavity - inflammatory#Infectious causes of rhinitis|rhinitis]]
 +
**Virus shed for a short time only
 +
*Also part of kennel cough ([[Viral infections#Infectious canine tracheitis|Infectious canine tracheitis]]), together with [[Bordetella bronchiseptica and Bordetella avium|''Bordetella bronchiseptica'']]
 +
*Control:
 +
**'''Live attenuated vaccine''' may be incorporated in multivalent vaccines
 +
***Immunity is short-lived
 +
***Only reduces severity of clinical signs
 +
 
 +
 
 +
===Bovine Parainfluenza - 3 (PI-3)===
 +
 
 +
*Virulence varies with isolates
 +
*Cessation of [[Respiratory system - general introduction#Mucociliary escalator|ciliary clearance]] and epithelial necrosis predisposes to secondary bacterial infections -> cough
 +
*May cause [[Viral infections#Parainfluenza- 3|rhinitis]] of cattle
 +
*With other agents causes [[Bacterial infections#Enzootic pneumonia of calves|calf pneumonia ]]
 +
**Together with managemental factors (overcrowding, poor ventilation, high humidity, deprivation of colostrum and stress caused by transport or mixing of stock)
 +
*'''Diagnosis'''
 +
**Diseased lung tissue from dead animals or centrifuged cells from lung lavage
 +
**Virus is too fragile for cell culture isolation (often inactivated intransport)
 +
**Antigen detection by ''' immunocytochemistry''' for intracytoplasmic viral inclusions containing labelled viral protein
 +
**Serology: 4-fold rise in ELISA antibody in paired serum samples from several animals
 +
*'''Control'''
 +
**Improve managemental factors
 +
**All-in, all-out systems
 +
**Some vaccination
 +
***Temperature sensitive mutant that replicates at 34<sup>o</sup>C but not at 37<sup>o</sup>C
 +
***Re-infection is common
 +
 
 +
 
 +
===Bovine Respiratory Syncytial Virus (BRSV)===
 +
 
 +
*'''Pathogenesis''':
 +
**More serious than [[Paramyxoviridae#Parainfluenza -3 (PI-3)|PI-3]]
 +
**Causes [Viral infections#Respiratory syncytial virus|respiratory infection]]
 +
**Replicates in nasal epithelium -> throughout upper respiratory tract -> bronchial tree
 +
**Syncytia form -> shed into bronchioles
 +
**Complications include [[Lungs - ventilation#Emphysema|emphysema]] and [[Lungs - circulatory#Pulmonary oedema|oedema]], drop in milk yield in adult cattle
 +
*'''Epidemiology''':
 +
**Subclinical reinfections are important in spreading disease
 +
**More than 70% of cattle in the UK have antibodies to BRSV
 +
*'''Diagnosis''' is same as for [[Paramyxoviridae#Parainfluenza -3 (PI-3)|PI-3]]
 +
*'''Control'''
 +
**Improve husbansry as in [[Paramyxoviridae#Parainfluenza -3 (PI-3)|PI-3]]
 +
**Vaccines are available but not effective as need to stimulate [[General Pathology - T-cell Activation and Function#Cytotoxic T-Cells|cytotoxic T-cells]]
 +
*<small>'''Reference''': Bryson, 1999, Update on calf pneumonia, CPD Veterinary Medicine, 1,3, 90-95</small>
 +
 
 +
 
 +
===Canine Distemper Virus (CDV)===
 +
 
 +
*Hosts: dogs, ferrets, seals, lions, mink
 +
*Has been a major pathogen of dogs prior to vaccination
 +
*Variable mortality depending on virulence
 +
*May occur subclinically
 +
*Involvement of central nervous system generally results in death
 +
*'''Pathogenesis''':
 +
**Aerosol infection
 +
**Infects alveolar [[General Pathology - Chronic Inflammation#Macrophages|macrophages]] or [[Oral Cavity - Oropharynx|oropharynx]]
 +
**Multiplies in the bronchial and other lymph nodes, infects monocytes and dendritic cells
 +
**Viraemia
 +
**Spreads via monocytes to a variety of epithelium depending upon the strain of virus
 +
**[[Viral infections#Canine distemper|Respiratory]] and alimentary tracts, skin and later (1-5 wk. post infection) to the brain
 +
*'''Clinical signs''':
 +
**Mucopurulent oculonasal discharge
 +
**Keratitis
 +
**[[Lungs - inflammatory#Interstitial pneumonia|Interstitial pneumonia]]
 +
**Severe clinical pneumonia follows secondary infection with [[Bordetella bronchiseptica and Bordetella avium|''Bordetella bronchiseptica'']]
 +
**Smelly sometimes bloody diarrhoea
 +
**Eruptions on the skin including hyperkeratosis of the nose and pads (hardpad)
 +
**[[PNS Repsonses to Injury#Segmental Demyelination|Demyelination]] (especially in cerebellum) -> incoordination or muscle tremors -> paralysis and coma or convulsions -> death
 +
**Encephalitis
 +
**Secondary pyogenic infections associated with immunosuppression and damage to epithelia
 +
**Recovered animals may have persistent or spasmodic chorea
 +
**The severity of the disease may vary; if enough neutralising antibody develops in the early stages, the virus maybe kept restricted largely to the lymph nodes.
 +
*'''Diagnosis''':
 +
**May present as series of infections
 +
**'''Immunocytochemistry''' of inclusion bodies
 +
***Intracytoplasmic inclusions may be found in most affected tissues
 +
***Inclusions persist longest in the brain (may be intranuclear) and the alveolar macrophages
 +
***Sections of fixed bronchial tissue, lung, macrophages, bladder may be used or nasal or conjunctival epithelium from live animals
 +
**Giant cells may be seen in the alveoli
 +
*'''Control''':
 +
**Live attenuated virus vaccines given at 10 and 12 weeks of age
 +
***Some now given at 7 and 10 weeks to allow socialisation
 +
**Homeopathic vaccines do not work
 +
**Live attenuated vaccines may kill some wildlife therefore '''Iscom vaccine''' is used in seal sanctuaries
 +
 
 +
*Can contribute to [[Viral infections#In Dogs|Infectious canine tracheitis]]
 +
*May be involved in [[Pancreas - inflammatory#Chronic interstitial pancreatitis|chronic interstitial pancreatitis]]
 +
*May cause [[Bones - developmental#Retention of elongated primary trabeculae|growth retardation lattice]]
 +
*May also trigger latent [[Tissue cyst-forming coccidia|Toxoplasmosis]] due to suppressing effect on lymphoid tissue
 +
 
 +
===Hendra Virus===
 +
 
 +
*Equine Paramyxovirus
 +
*Causes [[Viral infections#Hendra virus|respiratory infections]] with respiratory distress and paralysis
 +
*Potentially zoonotic (beware palpating inside the throat for obstruction)
 +
 
 +
 
 +
===Nipah Virus===
 +
 
 +
*Infects pigs and humans
 +
*Humans exposed to pig blood are at risk
 +
 
 +
 
 +
 
 +
 
 +
 
 +
<big><center>[[Viruses|'''BACK TO VIRUSES''']]</center></big>

Revision as of 12:46, 14 December 2007

BACK TO VIRUSES


Overview


Classification


Virus properties

Structure

  • Negative sense RNA, unsegmented, single stranded
    • -> Reasortment and antigenic shift cannot occur
  • HN spike contains:
    • Haemagglutinin (H)- attachment protein
    • Neuraminidase (N)
  • Fusion glycoprotein (F) spike
    • -> Viral lipid bilayer can fuse directly with host plasma membrane
      • -> RNA released into cytoplasm
    • ->Syncytium (multinucleated giant cells) in lesions and cell culture
    • Host antibody response to this protein is most important
      • Best induced by live attenuated vaccines

Growth in vitro

  • Allantoic cavity of 10-day-old eggs
  • Followed by haemagglutination

In vivo

  • Cell tropism for upper respiratory tract epithelium
    • All replicate in these cells
  • Some replicate in the gut
  • Most virulent replicate in lymphoid cells and neurons (Distemper, NDV)
  • Links to the readiness to cleave Fo and Ho precursors in different cells

Antigenic differentiation

  • Major conserved immunodominant virus-specific antigens on F and HN
    • -> Vaccines protect against all isolates of the same virus
  • Minor morbillivirus-specific epitopes on F
  • Minor variable epitopes of F, HN and NP
    • Allows antigenic fingerprinting


Newcastle Disease Virus (NDV)

  • Hosts
    • Gallinaceous birds, pigeons, parrots, finches
    • Subclinical carriers: ducks, ostriches
    • Causes conjunctivitis in humans
  • Epidemiology
    • Air-born
    • Direct contact of poultry
  • Diagnosis
    • Samples of trachea and gut of 20 birds are tested in eggs
    • HI using anti-NDV serum (to differentiate HA caused by avian influenza
    • Animal test: virulence of isolate tested by the speed it kills chicks
    • Sequencing the cleavage site of H gene
      • The more basic amino acids the more virulent the virus
      • Now replacing the animal test
  • Control
    • Isolation of stock
    • Vaccination of chickens and racing pigeons
    • Surveillance of imported exotic birds
    • Notifiable disease
    • Infected premises to be culle and firebreak cull if spread


Reptilian Paramyxoviruses

  • Infect central nervous system and lungs
  • Kill particularly snakes
  • Healthy reptiles may be carriers
  • Testing by serology - HI test
  • Aim to keep virus free collection and prevent spread back into the wild


Murine Parainfluenza - 1 (Sendai virus)

  • Endemic in many mouse colonies
  • Most mice show no symptoms due to maternal antibodies
  • But minor respiratory lesions may invalidate carcinogenic or toxicological studies
  • Immunological studies also confused due to virus activating NK cells via high circulating IF 3-4 days post-infection
  • Control achieved by:
    • Purchasing specific pathogen free (SPF) mice
    • Kill whole colony in an outbreak -> disinfection -> formalin fumigation


Canine Parainfluenza - 2

  • or Parainfluenza - 5
  • Infects dogs
  • May cause mild upper respiratory infection, rhinitis
    • Virus shed for a short time only
  • Also part of kennel cough (Infectious canine tracheitis), together with Bordetella bronchiseptica
  • Control:
    • Live attenuated vaccine may be incorporated in multivalent vaccines
      • Immunity is short-lived
      • Only reduces severity of clinical signs


Bovine Parainfluenza - 3 (PI-3)

  • Virulence varies with isolates
  • Cessation of ciliary clearance and epithelial necrosis predisposes to secondary bacterial infections -> cough
  • May cause rhinitis of cattle
  • With other agents causes calf pneumonia
    • Together with managemental factors (overcrowding, poor ventilation, high humidity, deprivation of colostrum and stress caused by transport or mixing of stock)
  • Diagnosis
    • Diseased lung tissue from dead animals or centrifuged cells from lung lavage
    • Virus is too fragile for cell culture isolation (often inactivated intransport)
    • Antigen detection by immunocytochemistry for intracytoplasmic viral inclusions containing labelled viral protein
    • Serology: 4-fold rise in ELISA antibody in paired serum samples from several animals
  • Control
    • Improve managemental factors
    • All-in, all-out systems
    • Some vaccination
      • Temperature sensitive mutant that replicates at 34oC but not at 37oC
      • Re-infection is common


Bovine Respiratory Syncytial Virus (BRSV)

  • Pathogenesis:
    • More serious than PI-3
    • Causes [Viral infections#Respiratory syncytial virus|respiratory infection]]
    • Replicates in nasal epithelium -> throughout upper respiratory tract -> bronchial tree
    • Syncytia form -> shed into bronchioles
    • Complications include emphysema and oedema, drop in milk yield in adult cattle
  • Epidemiology:
    • Subclinical reinfections are important in spreading disease
    • More than 70% of cattle in the UK have antibodies to BRSV
  • Diagnosis is same as for PI-3
  • Control
    • Improve husbansry as in PI-3
    • Vaccines are available but not effective as need to stimulate cytotoxic T-cells
  • Reference: Bryson, 1999, Update on calf pneumonia, CPD Veterinary Medicine, 1,3, 90-95


Canine Distemper Virus (CDV)

  • Hosts: dogs, ferrets, seals, lions, mink
  • Has been a major pathogen of dogs prior to vaccination
  • Variable mortality depending on virulence
  • May occur subclinically
  • Involvement of central nervous system generally results in death
  • Pathogenesis:
    • Aerosol infection
    • Infects alveolar macrophages or oropharynx
    • Multiplies in the bronchial and other lymph nodes, infects monocytes and dendritic cells
    • Viraemia
    • Spreads via monocytes to a variety of epithelium depending upon the strain of virus
    • Respiratory and alimentary tracts, skin and later (1-5 wk. post infection) to the brain
  • Clinical signs:
    • Mucopurulent oculonasal discharge
    • Keratitis
    • Interstitial pneumonia
    • Severe clinical pneumonia follows secondary infection with Bordetella bronchiseptica
    • Smelly sometimes bloody diarrhoea
    • Eruptions on the skin including hyperkeratosis of the nose and pads (hardpad)
    • Demyelination (especially in cerebellum) -> incoordination or muscle tremors -> paralysis and coma or convulsions -> death
    • Encephalitis
    • Secondary pyogenic infections associated with immunosuppression and damage to epithelia
    • Recovered animals may have persistent or spasmodic chorea
    • The severity of the disease may vary; if enough neutralising antibody develops in the early stages, the virus maybe kept restricted largely to the lymph nodes.
  • Diagnosis:
    • May present as series of infections
    • Immunocytochemistry of inclusion bodies
      • Intracytoplasmic inclusions may be found in most affected tissues
      • Inclusions persist longest in the brain (may be intranuclear) and the alveolar macrophages
      • Sections of fixed bronchial tissue, lung, macrophages, bladder may be used or nasal or conjunctival epithelium from live animals
    • Giant cells may be seen in the alveoli
  • Control:
    • Live attenuated virus vaccines given at 10 and 12 weeks of age
      • Some now given at 7 and 10 weeks to allow socialisation
    • Homeopathic vaccines do not work
    • Live attenuated vaccines may kill some wildlife therefore Iscom vaccine is used in seal sanctuaries

Hendra Virus

  • Equine Paramyxovirus
  • Causes respiratory infections with respiratory distress and paralysis
  • Potentially zoonotic (beware palpating inside the throat for obstruction)


Nipah Virus

  • Infects pigs and humans
  • Humans exposed to pig blood are at risk



BACK TO VIRUSES
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