Paramyxoviridae Flashcards
What are the characteristics of Paramyxoviruses?
- 150-300nm
- Enveloped
- Pleomorphic
- Generally transmitted by aerosol
- “herring-bone” nucleocapsid
- -ve sense ssRNA
- Single segment of RNA (15-16kb)
What are the paramyxoviridae surface glycoproteins?
There are two types
- Antigenically Stable!
- Attachment proteins: HN, H or G depending on the virus genus
- Permits virus attachment to the host cell
- Neutralising ABs are directed against H, HN and G
- H and HN is a haemagglutinin???? - Fusion Protein
- Causes fusion of virus infected cells with uninfected cells
- The degree of viral virulence is highly correlated with the AA sequence of this protein
What does an effective vaccine against paramyxoviridae do?
Induces the production of ABs against both Attachment and Fusion viral surface proteins
What is syncytia?
Where the fusion of virus- infected cells and uninfected cells occurs
- Paramyxoviridae replication occurs in the cytoplasm
- forms intracytoplasmic inclusion bodies
Describe Bovine Parainfluenza 3…
- Associated with shipping fever and calf pneumonia
- Replicates in Upper Resp Tract
- Usually causes mild or subclinical effects
- Recovery usually occurs after a few days
- May be complicated by secondary bacterial infections
- Worsens if animals are stressed etc.
How do you diagnose Bovine Parainfluenza virus?
Difficult to diagnose
- Common occurrence of virus without the disease
- There are a variety of other agents that cause “shipping fever”
How do you control Bovine Parainfluenza virus?
- The immune response is strong but short-lived
- Reinfections occur readily
- BPIV-3 is included in some combo vaccines with IBR and BVD
Describe Bovine Respiratory Syncytial virus…
- Affects cattle and sheep
- Part of the “shipping fever” complex
- Respiratory disease in calves and young cattle
- Protection after infection is short-lived
- No vaccine!
What virus is part of Genus Avulavirus?
Newcastle Disease Virus
Describe Newcastle disease virus…
- Important disease of poultry
- Causes devastating epizootics
- Relatively resistant in the environment
- Causes major economic loss where it is enzootic
- Major threat where it is exotic
- There is one serotype but a number of pathotypes
- Infected birds shed the virus for at least 4 weeks
- Vaccine is available
Is Newcastle disease notifiable?
Yes!
What are some viruses that are members of the Morbillivirus Genus?
- Canine Distemper Virus
- Rinderpest Virus
- Peste-des-petits- ruminants virus
- Cetacean morbillivirus
- Phocine distemper virus
- Measles virus (people)
What are some fundamentals of Morbilliviruses?
- Target epithelial, neural and lymphoid tissues
- Cause highly contagious diseases
- Are very fragile in the environment
- Cell-mediated immunity is important in recovery
- Induce life-long immunity in survivors of infection
- A critical number of susceptible animals must be continuously available for the disease to persist
Describe Canine Distemper Virus…
- Now rare, due to vaccine
- Important cause of mortality in wild life
- Virus is shed in all body excretions from 5dpi for weeks
- Affects all Canidae and some Felidae
- Transmission by direct contact, droplet and aerosol
- Suggestions of wildlife reservoirs
- High morbidity and mortality in unvaccinated populations world wide
What are the clinical signs of Acute CDV?
- Incubation for 3-6 days
- Biphasic rise in temperature up to 41C
- Severe leucopenia, anorexia, conjunctivitis
- Predominantly respiratory ot GIT signs
- CNS signs can occur
