Forget anthrax and smallpox, influenza could easily be turned into the next weapon of mass destruction, scientists said today.
They sounded their warning as researchers come close to completing the blueprint for the virus of the 1918 'flu epidemic that killed up to 40 million people globally.
"Taken together with the fact that influenza virus is readily accessible and may be causing more deaths than previously suspected, the possibility for genetic engineering and aerosol transmission suggests an enormous potential for bioterrorism," the University of Texas scientists said.
Writing in the Journal of the Royal Society of Medicine, the team led by Dr Mohammed Madjid noted that last century a series of 'flu epidemics from Spain to Russia and Hong Kong had killed millions of people as the virus naturally mutated.
They pointed out that sequencing of the genome of the 1918 Spanish 'flu epidemic was nearly complete, opening the door to unscrupulous scientists to build an even more potent virus.
"Recently, the possibility of synthesising an infectious agent solely by following instructions from a written sequence has moved from theory to practice," they wrote.
The scientists also noted that while infection generally took place through personal contact, the disease was also easily transmissible through tiny droplets in the air.
A would-be bioterrorist needed only to spray an aerosol containing the weaponised virus inside a passenger plane to set off a global infection.
They pointed out that in contrast to agents such as smallpox which are carefully guarded, the 'flu virus was relatively freely available.
It had the added advantage that because it occurred naturally, the beginning of a purposely started outbreak would not set off alarm bells, giving the disease a major head start on the people trying to fight it.
Noting that its appeal to the bioterrorist also lay in the fact that it had a short incubation period and did not succumb to post-exposure immunisation, the scientists set out a list of demands for urgent action.
There should be more immunisation, they said, laboratory security should be raised, antiviral drugs should be stockpiled, there should be closer monitoring of outbreaks and governments should consider fitting filters and sensors to buildings.