Historical Perspective — Emergence of Influenza A (H1N1) Viruses

Swine Outbreak of Pandemic Influenza A Virus on a Canadian Research Farm Supports Human-to-Swine Transmission

“…Secondly, some individuals may have been incorrectly classified as positive for pH1N1 on the basis of cross-reactive serological test results. For example, 5% of staff may have had cross-reactive antibodies to pH1N1 from previous swine flu infections, seasonal vaccination, or vaccination for swine flu in 1976 [33][34][35]. To minimize bias from cross reactive serological test results, we compared acute and convalescent phase serological test results, compared serological analysis of pH1N1 and seasonal influenza strains, and statistically ruled out correlation between positive pH1N1 serological test results and age or prior receipt of the seasonal influenza vaccine.…”

Infectious diseases detection by microarray: An overview of clinical relevant infections

“…It caused 40 million deaths worldwide, followed by the 1957 pandemic influenza A (H2N2) resulting in approximately 1 million deaths worldwide. The third pandemic was in Hong Kong caused by the influenza virus A (H3N2) in 1968 [18]. The last recorded human pandemic was caused by the H1N1 strain in 2009, where the virus was propagated in 214 countries [19].There are also other respiratory viruses capable to cause substantial outbreaks, like the coronaviruses that caused severe acute respiratory syndrome (SARS) in China in 2002 which spread by 2003 in all five continents [20].…”

Molecular character of influenza A/H1N1 2009: Implications for spread and control

“…Infl uenza viruses of type A are subtyped by the antigenic characteristics of the HA and NA glycoproteins. Widespread human infection has for over a century been limited to viruses with HA subtypes H1, H1 and H3, and with NA subtypes of N1 and N2 [6,7]. Additional criteria used to identify an infl uenza virus include the source location, an identifying number, and the year of isolation.…”