The bird flu viruses do not normally infect people but with already 140 cases of infected people reported world wide there is raised concern. Most of these infections are caused by the individuals contact with a contaminated bird, or by individuals coming in contact with surfaces or materials that have been in contact with a contaminated bird. There is very few case of human to human transmission of the bird flu.
Scientists have determined that flu viruses originally originated from birds.
These viruses over the years have mutated and changed their genetic make up allowing them to infect humans. The way researchers suspected it worked was; the wild birds infect domestic poultry, the domestic poultry in turn infect pigs and/or dogs. The pig which can be infected with the human form of influenza can also be infected by avian influenza virus. The pig acted as a mixing bowl of sorts allowing the two viruses to interact and change their genetic make up allowing the avian virus the ability to infect humans. However a few years back scientists made a startling discovery that some avian flu virus can infect humans directly without going through the pig. This raised some concern. Instead of bird flu virus taking the time to transition to infecting humans via the pigs it was infecting humans directly which implied a quicker transition phase.
There a couple of viruses that have made the transition or jump from bird viruses to human virus.
These cause milder form of the flu since our immune system has had a chance to adopt. These so called “human flu’ s” though mild are still lethal to the very young, very old and those with compromised immune systems. When a bird flu virus first makes the transition from bird to human it is at its most lethal. The body hasn’t had a chance to develop immunity to the virus and relies on outside help to fight the virus. Help in the form of anti-viral medication.
The following outlines the steps of the spread of the bird flu to humans. First, the wild birds shed the virus through nasal or saliva secretions and or feces. Next, domestic birds come in contact with the contaminated materials, surfaces or secretions through the water, soil and/or contaminated feed. The domestic poultry contract the virus in a similar way to humans; poultry inhale the virus. Once the poultry has contracted the bird flu virus, the flu spreads quickly through a flock because of the close proximity of the domestic birds. If the bird flu virus was deposited in the soil, it can be transported to the next farm on the shoes of employees or on tractor tires, effectively spreading the bird flu to neighboring farms. The bird flu virus can survive for long periods of time in cool temperatures outside a host animal. The final step is the infection of the human population. Humans come in contact with the infected birds or contaminated surfaces.
This can happen at the open air markets or even at in a backyard.
The open air markets are normally crowded and unsanitary. Cock fights have also been implicated in the spread of the bird flu virus. The virus here can be contracted by simply touching an infected bird. In rural areas, the domestic poultry are free range birds and have a higher risk of contracting and passing the virus on to humans. These birds are closer contact with wild birds and humans. Some of these free range birds roam in and out of homes. With the advent of technology and ease of travel, the risk of the spread of the avian flu is increased. To date however the spread of the virus from bird to human is limited to the local level of market place, cock fights and home backyards.