RNA VIRUS - ORTHOMYXOVIRIDAE - Influenza virus Flashcards
Enveloped virus w/ a HELICAL nucleocapsid and SEGMENTED, SS-NEGATIVE RNA
Influenza virus
May serve as the “mixing bowl” w/n which the human, avian, swine viruses reassort
Pigs
Only a HUMAN virus
NO animal source of new RNA segments
does NOT undergo antigenic SHIFTS
undergo ENOUGH antigenic DRIFT
Influenza B virus
Causes worldwide epidemics (pandemics)
has 16 antigenically distinct types of HEMATOGGLUTININ
has 9 antigenically distinct types of NEURAMINIDASE
Influenza A virus
Major OUTBREAKS of influenza
does NOT lead to pandemic
Influenza B virus
Mild respiratory tract infection
does NOT cause outbreaks of influenza
Influenza C virus
Bind to the CELL SURFACE RECEPTOR (neuraminic acid, sialic acid) to initiate infection of the cell
the MOST IMPORTANT ANTIGEN
Hemagglutinin
the target of NEUTRALIZING ANTIBODY
Hemagglutinin
Cleaves neuraminic acid (sialic acid) to RELEASE PROGENY VIRUS from the infected cell
Neuraminidase
DEGRADES THE PROTECTIVE LAYER of mucus in the respiratory tract – ENHANCES the ABILITY of the VIRUS to GAIN ACCESS to the respiratory epithelial cells
Neuraminidase
MAJOR CHANGES based on the REASSSORTMENT of segments of the genome RNA
Antigenic SHIFT – PANDEMICS
*when human influenza A virus recombines w/ swine influenza A virus
MINOR CHANGES based on the MUTATION in the genome RNA
Antigenic DRFIT – EPIDEMICS
Incubation Period of Influenza virus
24-48 hrs
fever, myalgia, headache, sore throat, cough
Complications of Influenza
FATAL BACTERIAL SUPERINFECTION
- S. aureus
- S. pneumoniae
- H. influenzae
REYE’S SYNDROME
Used for both the treatment and prevention of influenza
Oseltamivir - DOC
Zanamivir
