There is a lot of information out there about the plague but we forget that during this time of year other flus exist as well. There are so many types that it can get confusing. I thought you moms out there might appreciate this primer on the flu bug itself.
In terms of classification of the various different types of virus that we have so far isolated, influenza is what is known as an RNA virus, meaning that the virus itself is primarily made up of different variations of ribonucleic acid. Because there are different forms of RNA at the ‘core' of the influenza virus, there are three different classifications:
• Influenza virus A;
• Influenza virus B;
• Influenza virus C.
Influenza virus A is the one that causes the most severe disease as it is an extremely virulent human pathogen. A huge variety of influenza virus A strains are naturally hosted by wild aquatic birds, and the genus is subdivided into many different individual strains, with all known flu pandemics having been caused by a variation of the influenza virus A genus.
Each variation of the virus A genus is identified by its reaction to antibodies, and many variations are seen more than once in a slightly modified form.
For example, the H1N1 ‘swine flu' variety that was first identified in early 2009 was in fact a variation of the same strain as that which caused the infamous Spanish flu outbreak in 1918 that was notable for killing millions of otherwise healthy young adults all over the world. The Asian flu pandemic that originated in China in 1956 was H2N2, whereas the Hong Kong flu pandemic of the late 1960s was the H3N2 strain of the virus A genus.
Unlike the virus A genus, influenza virus B is almost exclusively limited to humans, meaning that there is no relationship between the infection and birds and pigs as there is with the virus A genus. Because there is little inter-reaction between the flu viruses carried by humans and other creatures, virus B influenza very rarely evolves or mutates, meaning that most people develop a degree of immunity to this particular form of influenza at a relatively young age.
Influenza virus C does however have the ability to cross from humans to animals (and vice versa), specifically to and from dogs and pigs. Consequently, virus C variants can cause serious illness and also local epidemics, although the only influenza genus that is known to have the ability to become a pandemic are variations of the A genus.
For reasons that are not fully understood, the most common forms of flu tend to be seasonal, with most people suffering ‘ordinary' seasonal influenza during the winter months. Despite what you may have heard this type of flu is actually more virulent than other forms, including the bird flu!!!
