Difference between revisions of "Paramyxoviridae"

From WikiVet English
Jump to navigation Jump to search
(Redirected page to Category:Paramyxoviridae)
(8 intermediate revisions by 2 users not shown)
Line 1: Line 1:
−
#REDIRECT[[:Category:Paramyxoviridae]]
+
{{unfinished}}
 +
 
 +
{{toplink
 +
|linkpage =Viruses
 +
|linktext =VIRUSES
 +
|pagetype=Bugs
 +
}}
 +
<br>
 +
 
 +
=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:
 +
*''Paramoyxovirinae'':
 +
**[[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
 +
 
 +
=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)===
 +
*'''Pathogenesis''':
 +
**More serious than [[Paramyxoviridae#Parainfluenza -3 (PI-3)|PI-3]]
 +
**Causes [Respiratory Viral Infections - Pathology#Respiratory syncytial virus|respiratory infection]]
 +
**Replicates in nasal epithelium -> throughout upper respiratory tract -> bronchial tree
 +
**Syncytia form -> shed into bronchioles
 +
**Complications include [[Lungs Ventilation - Pathology#Emphysema|emphysema]] and [[Lungs Circulatory - Pathology#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 [[Lymphocytes - WikiBlood#Cytotoxic CD8+|cytotoxic T-cells]]
 +
*<small>'''Reference''': Bryson, 1999, Update on calf pneumonia, CPD Veterinary Medicine, 1,3, 90-95</small>
 +
 
 +
==Equine==
 +
===Hendra Virus===
 +
*Equine Paramyxovirus
 +
*Causes [[Respiratory Viral Infections - Pathology#Hendra virus|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 [[Lymphocytes - WikiBlood#Natural Killer (NK) Cells|NK cells]] via high circulating [[Innate Immune System - WikiBlood#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
 +
 
 +
=Other resources=
 +
*[http://www.pitt.edu/~super1/lecture/lec3401/index.htm On line Paramyxoviridae lecture by P. Russell]
 +
 
 +
 
 +
<big><center>[[Viruses|'''BACK TO VIRUSES''']]</center></big>

Revision as of 18:42, 13 October 2008


 This article is still under construction.


Infectious agents and parasitesWikiBugs Banner.png
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)

  • Pathogenesis:
    • More serious than PI-3
    • Causes [Respiratory Viral Infections - Pathology#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

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
Retrieved from "https://en.wikivet.net/index.php?title=Paramyxoviridae&oldid=39875"