Measles, Rubella, Varicella Flashcards
Members of the Paramyxovirus family of viruses - features
negative sense
single-stranded RNA virus
Large, helical
Enveloped
Parainfluenza virus is part of Paramyxovirus and orthomyxovirus is inflluenza (T/F)
True
Paramyxovirus is segmented and influenza is non segmented (T/F)
False; Paramyxovirus is non segmented and influenza is segmented
The family is divided into 3 genera
- Parainfluenzavirus
- Pneumovirus
- Morbillivirus
Pneumonia, bronchitis and croup, especially in children, and Mumps - under which genera of Paramyxovirus?
Parainfluenzavirus
Measles; Canine Distemper Virus - which genera of Paramyxovirus?
Morbillivirus
Respiratory Syncytial Virus (RSV), causes pneumonia - which genera of Paramyxovirus?
Pneumovirus
Is replication basically the same for all viruses in paramyxovirus group?
Very similar for all viruses in this group.
What is the diff in replication for viruses in paramyoxvirus group compared with influenza in same group?
All the action occurs in the cytoplasm for the other viruses
Unlike influenza, Paramyxovirus replication is resistant
to ________ _
Actinomycin D
Nucleocapsid - define
Viral genome encapsulated by the nucleocapsid protein; it is generally inside the cytoplasm.
Syncytium - define
a single cell or cytoplasmic mass containing several nuclei, formed by fusion of cells or by division of nuclei.
What occurs due to the syncytium formation in Measles Virus (MV)?
What are the MV cells referred to as?
A large excess of nucleocapsids are produced in infected cells, which form characteristic cytoplasmic inclusion bodies
Warthin Finkeldey cells
Measles virus (MV), a paramyxovirus, has two glycoproteins which are?
haemagglutinin (HA) and fusion (F) protein
Role of MV glycoproteins
responsible for virus attachment and entry
During MV infection, both the viral _________ are
synthesized in the ________ _________ and are
_______ to the cell surface where they cause _____ with the neighbouring cells
During MV infection, both the viral glycoproteins are
synthesized in the endoplasmic reticulum and are
transported to the cell surface where they cause fusion
(syncytium formation) with the neighbouring cells
Syncytium is rare in MV (T/F)
False; Syncytium is very common
Name one of the most infectious diseases known
Measles
Before ____ almost everyone contracted measles
1963
Known hosts for MV
Humans, monkeys, rodents
MV is the single leading cause of _______ _________
death among children in _____ - more than
AIDS, tuberculosis, and malnutrition
MV is the single leading cause of vaccine-preventable
death among children in Africa - more than
AIDS, tuberculosis, and malnutrition
Neuraminidase spikes absent in MV morphology (T/F)
True
Neuraminidases are enzymes that cleave sialic acid groups from glycoproteins, thereby freeing the virus to infect other cells in the host organism.
Pleomorphic – define
A term used in histology and cytopathology to describe variability in the size, shape and staining of cells and/or their nuclei.
MV - structural features
- pleomorphic spherical structures
- 100-250nm diameter
- Inner nucleocapsid contains coiled helix of ssRNA and three proteins
- Outer envelope contains three other proteins