These days all one seems to hear in India is "Bird Flu". The disease which has taken a major part of India in its grip, has not only severly affected the poultry industry of the nation but also it has sent panic bells ringing across the states - from Delhi in the North to Tamil Nadu in the South, to West Bengal in the East, the latter being worst affected. Even the World Health Organisation (WHO) has declared the current outbreak of Bird Flu in India as the worst case reported till date.

In the affected areas, chickens are being culled at a rapid pace, but still the disease is spreading its wings from one district to the other, from one state to another. One primary reason for the rapid spread of Bird Flu is the lack of awareness about the virus which causes the disease. Almost everyone knows that the disease is lethal, but not many know what causes it, how it spreads, and how it can be prevented.

Keeping in mind the scale and spread of Bird Flu virus that has taken its toll in India, Headlines India decided to give its readers an insight into the disease, which first broke out in 1997 in Hong Kong, affecting 18 people and claiming 6 lives.

Bird Flu, also known as Avian Flu, is an influenza caused by virus, which affects birds. It might sound surprising, but the fact is that birds, like humans, are vulnerable to influenza. Influenza viruses can be divided into three types (strains) -- influenza A, B and C. Type A is responsible for the deadly influenza pandemics. Type B can lead to smaller, more localized outbreaks. Type C, less common and more stable than other strains, has milder symptoms. Types B and C are usually found only in humans, whereas type A infects both people and animals, including birds, pigs, horses, whales and seals.

Bird Flu is caused by the H5N1 strain of virus, and is a type 'A' influenza. It usually affects chicken and other poultry birds such as ducks. Earlier, human infection was unheard of in Bird Flu. However, the virus spread from birds to humans in 1997, when six people in Hong Kong died of the disease. According to the data provided by World Health Organisation on February 1, 2008, approximately 225 people across the world have succumbed to the disease over the past five years.

It must be noted here that although the bird flu virus is highly contagious, it rarely causes any harm to the carrier. Thus, even while infected with an avian flu virus, the animal does not have "flu". Typically, flu virus is adapted by one species of bird, and in turn spreads to another species. This happens more with the domestication of chickens and turkeys, as the avian flu virus acquired by one species rapidly mutates and infects the other species as well. This rapid spread can be stopped only by killing every domestic bird in the affected area.

The H5N1 strain virus causes avian influenza. The highly pathogenic Influenza A virus subtype, H5N1 virus, is an emerging avian influenza virus that has been causing global concern as a potential pandemic threat. It is simply referred as "bird flu" or "avian influenza".

Over the years, H5N1 has evolved into a flu virus strain that infects more species of birds than any previously known flu virus strain. This strain is deadlier than any previously known flu virus strain, and continues to evolve becoming both more widespread and more lethal.

H5N1 has killed millions of poultry Asia, Europe and Africa. Although human transmission of the virus is rare, the recent cases of human infections have left the health officials worried. Health experts are concerned that the co-existence of human flu viruses and avian flu viruses (especially H5N1) will provide an opportunity for genetic material to be exchanged between species-specific viruses, possibly creating a new virulent influenza strain that is easily transmissible and lethal for humans.

With bird flu engulfing almost the entire nation, where 26 people with suspected symptoms have been kept in isolation, the disease is posing a potential threat to the country. The virus is spreading like wildfire, and in order to prevent the disease from affecting human beings, it is essential to have a thorough understanding of how bird flu affects human beings, the symptoms of the disease, its treatment and prevention measures.

Read our second Special Report in this series to know more about bird flu to protect yourself and your family from it.