All flu viruses originate from wild birds and due to changes in their genetic materials (mutations) they can adapt to infecting humans as well. The bird flu virus seems to exist in two different forms. The first is the mild form (low pathogenic) and the second form is the deadly (high pathogenic) form.
Understanding Bird Flu in Birds
Wild birds infected with the avian flu viruses rarely get sick and thus they are able to spread the disease effectively. If the bird flu virus infects domestic poultry it is deadly and contagious spreading quickly and dramatically through the flock. This is possibly because of the crowded conditions in which the poultry live allowing for easy spread.
Understanding Bird Flu in the Human Population
The first cases of bird flu in human the human population were reported in 1997 and since then there have been a total of 122 reported human infection cases with 60 deaths. Majority of the people who have died from the bird flu virus contracted the virus after coming in direct contact with infected birds and poultry. Public health officials have started preparing and warning of a possible bird flu pandemic caused by the deadly bird flu virus known as the H5N1. Understanding bird flu will give us a chance to better prepare for the bird flu pandemic. The bird flu virus attacks the cells that line the human airway. In the airway there are two kinds of surface cells (epithelial cells). There are the cells that have hair-like fringes (cilia) and those that do not have cilia. The common human flu viruses can infect both kinds of cells. The bird flu can only infect the cells that have the cilia. This is because these cells are familiar to the bird flu virus; the cells in the bird’s guts and airway are all ciliated (have hair like fringes). The bird flu viruses also attack the cells in the lower end of the human lung, in the areas where oxygen and carbon dioxide are exchanged. As a result of attacking cells that low in the lungs, coughing does not dislodge it, therefore minimizing its spread by coughing. The danger with the bird flu virus will become evident when it is able to transmit itself from human-to-human. There are two ways that it may be able to do this. The first way may happen when an individual or individuals are infected with both the bird flu virus and the human virus and the two viruses somehow exchange genetic material. This genetic mixing is behind the last two human pandemics; the Asian Flu of 1957 and the Hong King flu of 1968. The second way may happen when many human are infected by the virus, this will allow the virus to adapt and evolve to suit its purpose in the human body. It is suspected that this is what let to the infamous 1918 Spanish Flu.
Understanding the Bird Flu and its Difference from the Human Flu
A research team in Hong Kong in November 2005 in their bid to understanding bird flu discovered that the bird flu virus when compared to the human virus causes more inflammation in the lungs. Once a human is infected by the virus there are some proteins that trigger the inflammation response to the infection. The researches measured the amount of these response proteins in humans infected by bird flu virus and human flu virus. The levels of the response proteins in cells induced by the bird flu virus were ten times greater.