Cause Of Influenza, Antigenic Shift, Antigenic Drift, Fundamentals Of influenza Virus.

Real Cause And Severity Of Flu Deaths:

Winter seems to be the common source of Influenza and an average of about 30,000 to 40,000 people fall prey to this simple and common yet deadly epidemic in US alone an the facts the world over remain to be assessed. The reason for this alarming situation in a narrowed or broad perspective is a capacity of the virus to mutate and change very rapidly and with alarming unpredictability. The fact is that the onslaught is so sudden and varied that the vaccines for the ailment seem insufficient and unmatching with very little scope for handling the ever-changing virus strains.

The Fundamentals Of Influenza Virus:

The basic influenza virus can be placed in three groups: A, B or C, based on the virus structure.
Type A is the root cause of the life threatening influenza type.
B is the root cause of minor and limited sphere outbreaks.
Rare yet stable type is C, which has minor and mild symptoms.
Influenza B & C usually infect humans. But Type A influenza infects people and animals alike.
The type a influenza is sub divided into two types based on the surface protein.
Hem agglutinin (HA)
Neuraminidase (NA)
Fifteen distinct HA sub-types and nine NA sub-types are found to be in existence. But they can combine and mutate to give rise to a hoard of other types.

For example sub-types H1N1, H1N2 and H1N3 are usually the root cause of influenza in humans and H7N7 and H3N8 viruses infect animals. Nearly fifteen flu sub-types have been found to affect birds and the most lethal one is H5N1.

Type A influenza viruses can be further divided into specific strains, which constantly evolve. This quality and ability to mutate and change their inherent structure indiscriminately makes them so sudden and unpredictable and many times fatal.

Characteristics Of The Virus:

Change is the crux of all living things but influenza A virus changes rapidly, continuously and without any warning symptoms that they produce fatal results in many cases. This can happen in two ways.

Atigenic Drift: - These are minor but permanent and continuous changes in the inherent structure of a virus. The inefficacy of the virus to amend inherent errors that occur as they reproduce new strains give rise to new types of infection. Development of antibodies to resist the onslaught of a particular strain of virus that give rise to a particular type of influenza may not be enough to resist newer strains. The vaccine of the previous season and the shot taken earlier or in the last season or even long ago may prove incapable of warding off this season’s flu attack.

Antigenic Shift: - This takes place when two or more sub-types combine giving rise to a new type of virus. This results in an entirely new strain and as no known immunity is developed to the new viral infection, the spread can be faster resulting in wide spread illness and the fatality rate multiplies. Where one is a human influenza virus and if the greater the ability of the new strain to spread from person to person the greater would be the risk of the infection assuming global endemic nature and causing uncontrolled, recurrent human life loss (SOURCE: Mayoclinic.com).

Menu:

Real Cause And Severity Of Flu Deaths:

Characteristics Of The Virus: