Understanding H1N1

The WHO declared swine flu as a pandemic (an epidemic that is geographically widespread; occurring throughout a region or even throughout the world). So far it is the pandemic of 2009.There was panic around the world. What is this H1N1?

I am NOT talking about the symptoms or treatments or precautions to be taken or what one should do or what one should not do or when to meet a doc or diagnose or treat the flu or anything like that. What I discuss here is some very basics about the virus that cause swine flu.

What is A(H1N1)?

That is the technical name given to a virus that cause flu or what is called ‘swine flu’. There are basically three categories of virus that can cause influenza or flu in humans and they are Influenzavirus A,B and C. The swine flu virus belong to Influenza A virus family (Orthomyxoviridae family, to be specific).

Why is it called swine flu?

Swine flu has three stages. This virus can cause flu in pigs. This flu can spread from pig to pig and that is the first stage. Then this flu virus enters into humans (and undergoes some modifications) who are taking care of these infected pigs and that is the second stage. At the third stage, virus spreads from to human to human and that is what we are facing now. As we can see, the roots points to pig and hence somebody named it swine flu. But the cause of infection is NOT eating (cooked) pork.

Why this virus is named H1N1? Or what dose those number mean?

H (or HA) stands for hemagglutinin and N stands for neuraminidase. These two are proteins found on the surface of the virus. The number was given on the basis of its form/type. So far, 16 variants of HA has been identified (H1 to H16). Same is the case with N. There are 9 types of neuraminidase (N1 to N9). Swine flu virus has H1 type of hemagglutinin and N1 type of neuraminidase (other than these two proteins, an Influenza A virus has 9 more proteins in them).

Why does H1N1 cause pneumonia?

Not just the H1N1 but the all the viruses that comes under Influenza A category are said to be pneumotropic. That means these viruses have some special affinity for lung tissues. That is the reason why some people developed pneumonia after getting infected by H1N1 flu virus. People who had earlier history of lung related diseases are more prone to develop pneumonia and not every one who gets infected by H1N1.

Finally, how serious is H1N1 infection?

A very healthy person might not require any antiviral medicine (like Tamiflu). A combination of rest and nutrition is what our body needs to fight it out in most of the cases. It is like any other seasonal flu and mortality ratio (about 1%) is not very high (or that is what I understand from the statistics given by W.H.O). In MANY of the death cases, it is said that, those died had some history of other illness (like pneumonia, high blood sugar, asthma, bronchitis, hypertension etc or people who are less immune – means who used to catch seasonal diseases almost all the time).