We hear a lot about bird flu, or avian influenza in the news (scientific name of the virus is H5N1). There are speculations about a possible pandemic similar in scope to the Spanish Flu last century. However, how could this pandemic actually come to exist, and what will cause bird flu to become transmissible between humans?
The current situation
Bird flu is currently not transmissible between human beings. In other words; if a person has contracted the virus, and you come in contact with that person the chances of you being infected are very small. The bird flu is not mutated enough to actually spread among humans, so far it can only infect individual humans who have been in touch with either infected birds or their feces.
How this can change
Certain animals are called “mixing vessels” for viruses. This means that they can be infected with various virus strains, which can then “mix” in those animals to produce a new, potentially more powerful, virus. The mixing vessel for bird flu and the human flu is the pig.
How the virus infects our cells
To understand how a pandemic can actually become a reality, we first need to understand how the bird flu virus can become more infectious. This can happen through a mixing vessel, like mentioned above. The reason why the virus can mutate faster in a mixing vessel is because the vessel, in this case the pig, can be simultaneously infected by two different strains of virus.
A virus will infect our cells by recognizing certain proteins that are attached to the surface of our cells. These proteins are different in each animal, and because of that humans do not get the same diseases as for example dogs or cats do, and visa versa. However, the pig has some of the same protein types on their cells as humans do, and some of the same protein types as chicken cells have! As a result, it is possible for a pig cell to be infected at the same time with a human flu virus, and with a bird flu virus. Once both viruses infect the same pig cell, they mix with each other and out comes a new virus with the ability of infecting and spreading in humans.
A Pandemic is Born
When this happens we are looking at a possible pandemic. At that point, when the virus can actually infect human-to-human there is no real limit to how fast it can spread unless a vaccine is developed. Because it would be an entirely new virus, our bodies will not have any resistance against it and the virus can easily take over.
Prevention
To prevent the spread of bird flu and possible ‘mixing’ of the flu with human versions, it is imperative that pigs are kept completely separate from poultry. Although there are many specialized farms in North America and Europe, these animals are commonly housed together or close to each other in developing nations. Only by developing vaccines and keeping potential mixing vessels away from the virus source can we prevent a pandemic!
Read more about the bird flu here
Or find out more about an influenza pandemic