Expert: Florence M Rollwagen - 5/2/2008

Question
Dear sir,
We ,students working on a project about the development of viruses ,would like to ask you the following qustion:
What is the effect of the geographical area on the spred of these viruses(BIRDS FLUE,SARS)?

Answer
Hi Sofia and Mostafa:  Thanks for your question.

I'm not sure exactly what question you're asking, but I'll give it a try.  

Viruses need to be spread by host organisms.  So if we pick the influenza (flu) virus as an example we have to start with birds.  Birds are the reservoir of influenza.  The reservoir is an animal in nature where the virus lives and reproduces when it's not infecting humans.  The transmission of influenza from wild birds to domestic birds (ducks, geese) usually occurs when migrating wild birds mingle with their domestic cousins in large flocks.  The domestic birds "catch" the virus and then there is the potential for passing the virus to humans.  Humans have the potential to spread the virus by shipping live birds from farms to cities.  You will notice that in Asia, birds for food are sold alive and killed and prepared for the kitchen by the family cook.  Here in the west, we buy dead birds at the grocery.  So the potential for spreading the virus via live birds is higher in Asia than in the west.  

Once the virus enters the human population, the spread can occur much more easily, because humans travel so much.  Airplanes are an easy conduit for infected persons to spread infectious agents.

I hope this answers your question.  If not, just write back.

FM Rollwagen, PhD