RNA Viruse: Orthomyxoviruses And Paramyxoviruses Flashcards
(39 cards)
Genome of Orthomyxoviridae
Spherical
-ssRNA genome : appears as 8 separate molecules
HA-hemagglutinin and NA-neuraminidase protein **
Classification of Orthomyxoviridae
Influenza A and B viruses
Influenza C virus
Tick-borne Orthomyxoviruses
Influenza A and B
Type A does not share ag with Influenza B
Many sub-types
Differ in HA or NA protein
14 subtypes of HA
9 subtypes of NA
Type specific antigens for Influenza A,B
Nucleoprotein
Matrix protein
Hemagglutinin
Sites for attachment to infect host cells (Salic acid)
H1-H15
Neuraminidase
Remove neuraminic acid from mucin and release from cell
N1-N9
Antigenic shifts of which protein results in pandemics
Haemagglutinin
Antigenic drifts in which proteins result in epidemics
Hemagglutinin
Neuraminidase
Forming new subtype
Antigenic shift
Forming new strain of virus
Antigenic drift
Large change in nucleotides of RNA
Antigenic shift
Small mutation of RNA
Antigenic drift
Occurs as a result of genome reassortment between difference subtypes
Antigenic shift
Occurs as a result of the accumulation of point mutations in the gene
Antigenic drift
An antigenic change can alter antigenic sites on the molecule such that a vision can escape recognition by the hots immune system
Antigenic drift
An antigenic change which results in severe alternation in HA or NA subtypes
Antigenic shift
Large and sudden mutation
Antigenic shift
Random and spontaneous mutation
Antigenic drift
Genome of Influenza C
Distinct genus
7 RNA segments
Single envelope glycoprotein in Influenza C function as HA
HEF—> fusion protein and esterase
Mutation capacity of HA,NA influence
The virulence
Replication of Orthomyxoviridae
In ciliated columnar epi of respiratory tract
In Orthomyxoviridae inflammatory response produced by CD4 T cells contributes to
Pneumonia
Clinical features of Orthomyxoviridae
Abrupt onset of fever, sore throat, nonproductive cough, myalgia, headache, malaise
Uncomplicated syndrome: 3-7 days
Wakness and cough: 2-3 weeks