A Brief History of the Avian Influenza H5N1 Virus

Although many different influenza viruses infect birds and have for many years, the history of the avian influenza H5N1 virus in humans is relatively brief, because the first cases noted occurred in 2003 in China and Viet Nam, according to the World Health Organization (WHO). The WHO only reports confirmed cases, in which the presence of H5N1 avian influenza microbes have been detected using blood tests or swabs of the infected person's nose or throat.Wild birds carry the viruses, but they are usually unaffected by them. However, in domesticated birds (chickens, ducks and turkeys) the viruses cause sickness and sometimes death. Symptoms may be mild causing ruffled feathers and low egg production or severe causing disease that affects multiple organs and death in 90-100% of flocks in as little as 48 hours. It is believed that the degree of difference in avian flu symptoms is related to the strain of the flu virus infecting the birds. H5N1 avian influenza microbes cause severe symptoms in poultry and in many cases entire flocks must be destroyed to prevent the spread of the disease.Infection with avian influenza microbes among humans is rare and usually occurs in persons handling or tending infected flocks of poultry and most strains, causing only mild illnesses. The history of the avian influenza H5N1 virus has shown that this strain can be deadly to humans as well. There have been 253 confirmed cases in humans since 2003, resulting in 148 deaths. This high percentage of fatalities (58%) following infection with avian influenza microbes has scientists and public health officials throughout the world worried. Viruses normally change slowly over time and the human immune system can identify them, because they are so similar to previously existing viruses and respond to them quickly. On rare occasions in the past, viruses have changed suddenly, referred to as "antigenic shift", causing severe illness, numerous human deaths and worldwide epidemics. Sometimes these viruses had not previously infected humans, but had infected other animals, such as pigs or birds. Or, they had not been highly contagious among humans, as with the H5N1 strain, but suddenly change and become easily transmitted from one human to another. Since the history of the avian influenza H5N1 virus has shown that it can infect humans, scientists believe that it could become highly contagious among them, causing pandemics or worldwide epidemics. Scientists believe that only two proteins in the H5N1 avian influenza microbes would need to change in order for it to become as easily transmitted among humans as the seasonal flu. Currently, if you do not have contact with wild birds or domesticated poultry in countries where H5N1 has been identified, then you run no risk of contracting the disease. This year, in 2006, most human cases have occurred in Indonesia. The WHO updates the history of the avian influenza H5N1 virus on a regular basis at its website. For more information about bird flu and natural products that can help build a strong immune system, please visit www.immune-system-booster-guide.com.

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