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About the Authors:
Nedzad Music
Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
Adrian J. Reber
Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
Aleksandr S. Lipatov
† Deceased.
Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
Ram P. Kamal
Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
Kristy Blanchfield
Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
Jason R. Wilson
Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
Ruben O. Donis
Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
Jacqueline M. Katz
Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
Ian A. York
* E-mail: [email protected]
Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
Introduction
Influenza viruses are common human respiratory pathogens that infect millions of people annually and cause an estimated 0.5 million deaths globally [1]–[4]. Seasonal human influenza viruses, including H3N2 and the 2009 pandemic H1N1 (H1N1pdm09) viruses, usually initiate infection in the upper respiratory tract. Clinical symptoms including fever, dry cough, sneezing, myalgia, and lethargy begin a few days after infection. In most cases, the upper respiratory tract infections are then cleared and the individual develops immunity to the specific strain of virus, although antigenic variants (“drifted” viruses) may escape this immunity to infect the same person in subsequent years. The disease caused by influenza infection is occasionally severe, especially when the virus spreads to the lower respiratory tract. As well, for reasons that are as yet unclear, influenza infection predisposes patients to secondary infection with bacteria, such as Streptococcus pneumoniae or S. pyogenes that rarely cause serious infections alone, and this superinfection is linked to increased disease severity [5]–[7].
A variety of animal models have been used to characterize the host and its immune response to infection, disease course, pathogenesis, and transmission of influenza viruses, as well as for the development of diagnostics, therapeutics, and vaccines [8], [9]. Commonly-used animal models include mice, guinea pigs, ferrets and...