-First documented influenza pandemic began in Sicily in 1510, spread to Italy, and then to the rest of Europe.
-The nomenclature system created for influenza virus A includes the natural host of origin, the geographic location of first isolation, strain number, and the year of isolation along with the HA and NA subtype in parenthesis; for example, the scientific nomenclature for “Swine flu” is A/swine/Iowa/15/30 (H1N1) (Rapid, 2012).
-Influenza virus B nomenclature is by the absence of the subtypes in parenthesis since there are no subtypes.
-If the natural host of origin is human, whether it is influenza A or B, there is no need to add it to the nomenclature (Rapid, 2012).
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-There have been three human pandemic outbreaks in the 20th century worldwide; 500 million deaths in 1918, 2 million in 1957, and 33,800 in 1968.
-Influenza viruses exist in three genera, A, B, and C, and belong to the orthomyxoviridae family (Rapid, 2012). -Influenza C is described as a common day cold-like disease (Rapid, 2012). -Unlike influenza B, influenza A has a numerous amount of classification subtypes divided based on their surface glycoprotein, haemagglutinin (HA) and neuraminidase (NA) -Influenza affects a variety of mammals such as: pigs, horses, cats, seals, whales, and mink (Rapid, 2012). -There are 16 HAs and nine NAs classification of influenza A and are distinguish through serological test by the antibodies that they react to (Rapid, 2012). -Horses are predominant host for influenza subtype H7 and H3; N7 & N8 -Pigs are predominant host for H1, H2, and H3 -Humans are predominant host for H1, H2, H3, H5, H7, and H9 -Humans and pigs are predominant host for N1 and N2 (Rapid, 2012). |