Bird Flu in Humans, Pandemic in the offing?

So, is the Avian Influenza going to be pandemic, a world wide epidemic? Right now, though the virus behind the current nightmare, Avian Influenza A(H5N1) is not tamed yet, it has not yet got the ability to spread among humans.

Until, it acquires such capacity it can’t go pandemic. The species barrier it needs to overcome to adapt to humans seems to be blissfully substantial.

When a person infected with Avian Influenza A(H5N1) coughs or sneezes, the virus is inhaled by close contact to them. It is the usual way of unintentional spread between humans.

However, health workers, who are in close contact to infected person, are exposed to the deadly virus through contact, unless extreme professional care is taken and the patient is treated in isolation.

If a person who comes in contact with dead or live infected birds and animals, their meat, secretions and excretions, contaminated surfaces etc they have to be very conscious of hygiene and strict cleanliness, otherwise they run a real risk of being infected with the bird flu.

Depending on the treatment given and the stage of disease when treatment is started as well as the response of the patient, the disease may abate leading to a full recovery or aggravate further which can result in death.

The inhaled virus, when landing in the upper respiratory tracts of the host would find it very difficult or impossible to break into the cells of respiratory tract wall. Only taking it deep down into respiratory system and prolonged exposure (to give ample chance for a break in to happen) causes infection.

However the hemagluttinin surface protein spikes of the Avian Influenza A(H5N1) virus, has adapted to the birds it infects, this is why the virus is transmittable to other birds.

The worry is, it will mutate and adapt to humans and cross the species. Originally it could not lock well into receptors of the human cell walls therefore failing to infect in upper respiratory tracts and failing to spread among humans. The worry is that the virus will mutate to allow this to happen.

At the moment as in case of poultry workers and close contact of patients, the prolonged exposure to a substantial amount of the virus, may prove different.

The proteins may eventually lock into the receptor on human cells, and once this is achieved, the replication process starts and the virus begins to invade.

Tamiflu (oseltamivir) drug when administered, blocks the neuramindase protein spike of virus and prevents the exit of newly multiplies cells out of host human cells, preventing the spread of virus in body. It can be quite effective, however it is a drug that is very expensive and not a 100% effective.

Unless, the virus naturally evolves, to make the required surface protein spikes to match human cell receptors or it goes through a gene swapping process, called reassortment of genes, with existing human flu viruses capable of spreading between humans, it can not spread among the humans on its own. However the evolving process may also make a virus less lethal and ill replicating). 

This effectively prevents a bird flu pandemic from developing, despite increased lethality and drug resistance of the Avian Influenza A(H5N1) virus. But it indeed, is a time bomb ticking, with no one sure when it will go off.

Let's hope a good vaccine will be developed and mass produced before that happens.