Infection
Influenza viruses are primarily transmitted through respiratory ______.
droplets
The first step in the viral life cycle of a productive infection, _________, involves specific interaction between protein molecules on the surface of the virion and molecules on the surface of the host cell.
adsorption
Influenza infection triggers various forms of programmed cell death in infected cells which result in the ________ of affected tissues.
inflammation
Recommended for most individuals aged 6 months and older, the influenza _______ remains the best way to protect against the flu and its potential complications.
vaccine
Influenza virions have ________ capsids meaning they have a lipid bilayer membrane studded with surface glycoproteins and exit the cell through budding or cell lysis.
enveloped
Influenza enters the host cell via receptor-mediated endocytosis through a process called _______.
viropexis
The cellular response to influenza infection involves __________, which involves the immediate, non-specific defense mechanisms, and __________, which involves the development of long-term, specific immunity.
innate immunity/adaptive immunity
Influenza is typically an _________, meaning it's short-term, however some people may experience prolonged symptoms or develop secondary infections that can lead to more serious __________.
acute infection/chronic infection
Influenza is a ____________, which are characterized by high levels of viral replication, production of new viral particles, and cell lysis of the infected cell.
productive infection
New viral proteins and gene segments are produced and assembled via:
transcription, translation, and genome replication.
Influenza viruses primarily infect and replicate within the ________ lining the respiratory tract, leading to cell damage and disruption of the respiratory system's normal function.
epithelial cells
The primary respiratory symptoms of influenza include:
cough, sore throat, and runny/stuffy nose
Influenza has a ________ genome. This means the viral RNA cannot be directly translated into proteins. Instead, it must first be converted into a positive-sense RNA by a viral enzyme called RNA-dependent RNA polymerase before it can be used to produce viral proteins.
(-)ssRNA
Influenza virions have a _______ symmetry within their nucleocapsid structure.
helical
Enveloped viruses can evade the host immune system by changing the surface proteins on their envelope, which act as targets for antibodies. This _________ allows for the development of persistent infections.
adaptability
If influenza is not treated, it can lead to a secondary infection such as _____________ (name one example from the lecture slides)
secondary bacterial pneumonia/chronic heart or lung disease/otitis media
Upon inhalation, influenza's attachment protein _______ binds to specific receptor molecules on the surface of cells in the respiratory tract, initiating the infection process.
hemagglutinin
Influenza virus, like most enveloped viruses, releases from the cell primarily through a process called ________.
budding
________ trigger an antiviral state in nearby cells, typically preventing viral replication and spread. However, influenza viruses have evolved mechanisms to counteract this response.
Type I interferons
The release of inflammatory mediators causes systemic symptoms like:
fever, chills, headache, muscle aches (myalgia), and fatigue