H5N1 five mutations away from a pandemicto become efficient at transmission?
Only five mutations in 2 genes are needed for H5N1 to become efficient at transmission in mammals without losing any of it's virulence.
Ron Fouchier of Rotterdam Medical Center found out which mutations were needed.
Now there was a trick they used. At first they added three mutations known to make bird flu transmissible to mammals. This gave the version we flubees have known through news reports.
It didn't transmit between ferrets but in these tests they are separated in cages. We have seen some first (and possible second) generation infections in humans between parents and kids (not neccesarily in that order) or kids & kids which can be contributed to closer contact. Flu can be transmitted by touch (wipe nose touch kid etc) and i think they keep the ferrets out of touching range since the point is demonstrating airbourne transmission in the ferret experiments.
The next step was infecting new generations of ferrets with that virus and after ten passenges or generations of growing
the virus in ferrets it gained the ability to to transmit without losing much of the virulence.
Now the last phase is a bit like cheating because the scientists make sure it's transmitted every time which is better then out there in the real world.
On the other hand all mutations have been seen before in bird flu, just not together. This research shows it's possible for H5N1 to become a pandemic.
It's a lot more difficult in real life compared to the labs and there's no point losing sleep over this (if you feel inclined go read the economy forum).