Difference between revisions of "Paramyxoviridae"

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#REDIRECT[[:Category:Paramyxoviridae]]
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{{toplink
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|linkpage =Viruses
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|linktext =VIRUSES
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|pagetype=Bugs
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}}
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<br>
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=Introduction=
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=Morphology=
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*Single-stranded negative-sense unsegmented RNA virus
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*Reassortment and antigenic shift cannot occur
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*Spike proteins include
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**'''HN''' (Haemagglutinin and Neuraminidase)
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**'''F''' (Fusion glycoprotein), which allows the virus to fuse directly to the plasma membrane and release its RNA
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***F also causes syncitium to form, which aids diagnosis
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***Host antibody response to the F protein is the basis for vaccination
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=Virulence=
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*Paramyxoviruses replicate in the epithelium of the upper respiratory tract as well as occasionally in the gut
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**Sites of spike protein cleavage
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*Virulence varies by virus, see below
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=Types and Subtypes=
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Paramoyxoviridae was reclassified in 2000 to include 2 subfamilies and 5 genera:
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*''Paramoyxovirinae'':
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**[[Bovine Parainfluenza - 3 (PI-3)| Bovine Parainfluenza 3]]
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**[[Canine Parainfluenza - 2 (aka Parainfluenza - 5)]]
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**[[Paramyxoviridae#Murine Parainfluenza - 1 (Sendai virus)|Murine Parainfluenza 1 (Sendai virus)]]
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**[[Newcastle Disease Virus (NDV)]] - avian paramyxovirus serotype 1
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**Avian Paramyxoviruses serotypes 2-9
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**[[Paramyxoviridae#Reptilian Paramyxoviruses|Reptilian Paramyxoviruses]]
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**Mumps
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**''Morbilliviruses''
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***[[Canine Distemper Virus (CDV)]]
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***Rinderpest
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***Pest de petit ruminant (PPR)
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***Measels
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***Seal virus - phocine distemper
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***Dolphin Morbillivirus
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***[[Paramyxoviridae#Hendra Virus|Hendra virus]]
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***[[Paramyxoviridae#Nipah Virus|Nipah virus]]
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*''Pneumovirinae''
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**[[Paramyxoviridae#Bovine Respiratory Syncytial Virus (BRSV)|Bovine Respiratory Syncytial Virus (BRSV)]]
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**Turkey Rhinotracheitis Virus
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=Antigenic Variation=
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*Antigenic conservation allows some cross protection by vaccination:
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**Conservation of major virus-specific F/HN antigens means vaccines protect against '''all isolates''' of the same virus
 +
**Minor morbillivirus-specific epitopes on F allows some cross protection between '''canine distemper, measles, and rinderpest'''
 +
*Antigenic "fingerprinting" is possible for some viruses based on minor variable epitopes of HN, F and NP on specific isolates as detected by monoclonal antibodies
 +
**These are detected by immunostaining infected cells
 +
 
 +
=Paramyxoviridae by Species=
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==Avian==
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===[[Newcastle Disease Virus (NDV)]]===
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==Canine==
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===[[Canine Parainfluenza - 2 (aka Parainfluenza - 5)]]===
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 +
===[[Canine Distemper Virus (CDV)]]===
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 +
==Bovine==
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===[[Bovine Parainfluenza - 3 (PI-3)]]===
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 +
===[[Bovine Respiratory Syncytial Virus (BRSV)]]===
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==Equine==
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===Hendra Virus===
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*Equine Paramyxovirus
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*Causes [[Respiratory Viral Infections - Pathology#Hendra virus|respiratory infections]] with respiratory distress and paralysis
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*Potentially zoonotic (beware palpating inside the throat for obstruction)
 +
 
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==Porcine==
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===Nipah Virus===
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*Infects pigs and humans
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*Humans exposed to pig blood are at risk
 +
 
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==Reptiles==
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===Reptilian Paramyxoviruses===
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*Infect central nervous system and lungs
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*Kill particularly '''snakes'''
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*Healthy reptiles may be carriers
 +
*Testing by serology - '''HI test'''
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*Aim to keep virus free collection and prevent spread back into the wild
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==Rodentia==
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===Murine Parainfluenza - 1 (Sendai virus)===
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*Endemic in many '''mouse''' colonies
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*Most mice show no symptoms due to maternal antibodies
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*But minor respiratory lesions may invalidate carcinogenic or toxicological studies
 +
*Immunological studies also confused due to virus activating [[Lymphocytes - WikiBlood#Natural Killer (NK) Cells|NK cells]] via high circulating [[Innate Immune System - WikiBlood#Interferons|IF]] 3-4 days post-infection
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*Control achieved by:
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**Purchasing specific pathogen free (SPF) mice
 +
**Kill whole colony in an outbreak -> disinfection -> formalin fumigation
 +
 
 +
=Other resources=
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*[http://www.pitt.edu/~super1/lecture/lec3401/index.htm On line Paramyxoviridae lecture by P. Russell]
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<big><center>[[Viruses|'''BACK TO VIRUSES''']]</center></big>

Revision as of 18:59, 13 October 2008



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VIRUSES



Introduction

Morphology

  • Single-stranded negative-sense unsegmented RNA virus
  • Reassortment and antigenic shift cannot occur
  • Spike proteins include
    • HN (Haemagglutinin and Neuraminidase)
    • F (Fusion glycoprotein), which allows the virus to fuse directly to the plasma membrane and release its RNA
      • F also causes syncitium to form, which aids diagnosis
      • Host antibody response to the F protein is the basis for vaccination

Virulence

  • Paramyxoviruses replicate in the epithelium of the upper respiratory tract as well as occasionally in the gut
    • Sites of spike protein cleavage
  • Virulence varies by virus, see below

Types and Subtypes

Paramoyxoviridae was reclassified in 2000 to include 2 subfamilies and 5 genera:

Antigenic Variation

  • Antigenic conservation allows some cross protection by vaccination:
    • Conservation of major virus-specific F/HN antigens means vaccines protect against all isolates of the same virus
    • Minor morbillivirus-specific epitopes on F allows some cross protection between canine distemper, measles, and rinderpest
  • Antigenic "fingerprinting" is possible for some viruses based on minor variable epitopes of HN, F and NP on specific isolates as detected by monoclonal antibodies
    • These are detected by immunostaining infected cells

Paramyxoviridae by Species

Avian

Newcastle Disease Virus (NDV)

Canine

Canine Parainfluenza - 2 (aka Parainfluenza - 5)

Canine Distemper Virus (CDV)

Bovine

Bovine Parainfluenza - 3 (PI-3)

Bovine Respiratory Syncytial Virus (BRSV)

Equine

Hendra Virus

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

Porcine

Nipah Virus

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

Reptiles

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

Rodentia

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

Other resources


BACK TO VIRUSES