The Bird Flu Facts and History
Realizing the Current Threat of the Avian Influenza Virus
The avian influenza A H5N1, also known as bird flu, is a serious health threat. According to the World Health Organization, the current strain of bird flu has killed 211 of the 343 people who have become infected since December 2003. The disease starts in wild birds who then spread it to domestic types such as chickens, turkeys, and ducks.
The Facts: How Humans Get It
While it is still rare for humans to get the virus, most cases of avian flu in humans have come from contact with infected poultry or their excretions, but not by eating their meat. It is not easy for humans to get the A H5N1 virus and if a person is infected, it is very difficult for them to give it to another person. However, all influenza viruses can change, and experts are worried that if someone gets a human flu virus and the avian flu virus at the same time, the two viruses may mutate and create a new one that could easily be passed between humans, causing a pandemic that could kill millions.
The History: Bird Flu Killed 40 Million People in 1918
The influenza pandemic of 1918, also known as the Spanish flu, killed 40 million people worldwide, possibly more. It was caused by a deadly strain of influenza A H1N1. Scientists have been studying frozen samples from those killed by the Spanish flu. One of their findings is that the virus developed in birds and is similar to the current bird flu virus A H5N1. They have found several mutations in the 1918 virus that also appear in the current one. The findings suggest that both strains show an ability to go from animals to humans without having to first combine with a human flu virus. Human immune systems have no immunity to a purely avian virus which is what could cause a pandemic.
Getting the Flu Shot May Help
New research released in December 2007 from Italy shows that getting the regular seasonal flu vaccine may provide a small amount of protection against bird flu. Researchers at the National Institute for Infectious Diseases in Rome added the A H5N1 virus to blood samples of volunteers who had gotten the flu shot. They found that some of the volunteers’ antibodies acted against the bird flu virus. The researchers also found a few immune cells, called CD4 T-cells, seemed to recognize and act against the current virus. The seasonal flu shot increased the frequency of such reactive CD4 T-cells.
This echoes what researchers discovered about the 1918 strain. What was unusual about the 1918 flu was that it mostly killed healthy young adults between the ages of 20 and 40, as opposed to the elderly, the very young or the weak. When researchers injected mice with current flu vaccines they seemed to have some resistance to the 1918 strain. This has lead them to believe that people over 40 years old were not killed by the 1918 strain because more than likely they had already had an H1 virus in their life and therefore had built up some immunity. Since the seasonal flu shot contains three influenza virus strains – one influenza A H3N2 virus, one influenza A H1N1 virus, and one influenza B virus – it gives the same opinion that exposure to previous strains could possibly help build some immunity to new strains, even avian flu strains.
Some drug companies are working on a vaccine against pandemic bird flu, and preliminary testing is encouraging but it is likely that any vaccine would just be stockpiled by the government and only made available if an outbreak occurs.
