In the theatre of modern terror, a pandemic is no longer viewed as just a health problem.
The impact on economies and people's sense of security can be huge as an outbreak plays on the popular imagination, and fear sets in, says Professor Richard Coker.
The outbreak of the severe acute respiratory syndrome (Sars) in 2003 was not the result of a terrorist act. But the cost to the world economy is estimated at around US$50 billion. About 8,000 people were infected and more than 700 died, including 33 in Singapore.
While terrorists use violence to create shock, awe and fear, the fear factor that is triggered when a pandemic sweeps the world can become larger than the disease itself, Prof Coker explains.
"A terrorist mastermind's aim is to create social disruptions and he can do this by playing on man's fear of the disease.
"You can generate mass panic without killing a lot of people," says the lean and tall 53-year-old who trained at Imperial College School of Medicine and later became a consultant to St Mary's Hospital, London.
Now, he heads the infectious diseases programme at the Saw Swee Hock School of Public Health, National University of Singapore. He is also a professor of public health at the London School of Hygiene & Tropical Medicine. His research interests include communicable diseases, emerging infectious diseases and pandemic preparedness.
He recalls a scare he experienced when news broke of the death of former Russian agent Alexander Litvinenko in 2006 in a London hospital.
The agent died of poisoning by radioactive matter believed to be polonium-210. Traces of polonium were later found across London and even on aircraft that had been to Moscow.
Not long before, Prof Coker had taken a flight from Moscow to London. He was among the thousands who received a letter from the authorities saying that he might have been exposed to the poison and needed to go for tests.
More than 1,000 people jammed the London authorities' telephone lines, afraid that they had polonium poisoning. "I had never heard of polonium, an odourless, tasteless substance. It created a lot of anxiety for those who were exposed to it as well as those who were suspected of being exposed to it," discloses Prof Coker.
His work on infectious diseases is valued by security agencies like Singapore's National Security Coordination Secretariat (NSCS).
An NSCS spokesman said that present-day threats to the national security landscape are faceless and evolving.
"It goes beyond the traditional and narrow definition of terrorism to include more diverse issues such as cyber security and pandemics.
"Similar to terrorism, these emerging threats can develop quickly and cause interconnected failures that affect the well-being of a nation and the safety of its citizens," he says.
Professor Rohan Gunaratna from the S. Rajaratnam School of International Studies (RSIS) warns that terrorists are recruiting scientists to create dangerous pathogens.
"Unless governments and their partners are prepared, a bioweapon will spread almost the same way as a pandemic."
If terrorists can create a synthetic virus like smallpox, they can turn it into a bioterror weapon. Once released in the air, the disease spreads rapidly and can turn into a pandemic.
"It is a weapon of the future, and we are only a short while away from a competent scientist joining a determined terrorist group," he cautions.
The success of Japanese doomsday cult group Aum Shinrikyo in killing 13 people in a sarin gas attack in Tokyo, as well as Al-Qaeda's attacks around the world, hinged on their ability to recruit scientists, he adds.
Among Al-Qaeda's ranks are science-trained professionals. They include Yazid Sufaat, a Malaysian former army captain with a science degree from the United States.
He is alleged to have headed Al-Qaeda's anthrax programme.
In 2010, Israeli security agencies arrested and detained Samir al-Baraq, a biology student born in Kuwait, who subsequently became active in the Al-Qaeda chemical division.
Ms Nur Azlin Mohamed Yasin, an RSIS researcher who studies cyber-terrorism trends, refers to an Al-Qaeda appeal for doctors to help them carry out germ warfare.
In last April's issue of the slick Al-Qaeda-linked magazine Inspire, a call was made to doctors who wanted to support terror attacks.
The text read: "Create lethal poison (gaseous), manufacture anthrax and give the mujahideen medical advice in your blogs, or you can contact us directly."
Terrorist groups are believed by some analysts to advertise openly to divert the attention and resources of intelligence units monitoring them.
Ordinary people are also scared into believing that experts are being recruited.
Ms Nur Azlin adds that several extremists are posting ways of making deadly poisons on their forum pages. In one posting, tips were given on how to mix cyanide with skin conditioner.
A posting that drew a huge positive response from readers suggested poisoning American soldiers in the Middle East with large doses of an anti-coagulant drug.
"Postings on poisoning the enemy are growing steadily. We are classifying this development as 'drugs of mass destruction' and we are monitoring the situation closely," she says.
Understand the enemy
What should be done if terrorists do succeed in creating a synthetic virus or bacterium that can cause a pandemic?
Prof Coker says that in any pandemic outbreak, it is essential to identify the cause of the agent, isolate it and contain it.
There are also lessons to be learnt from each pandemic. "Anticipating pandemics and their origins is tricky," he says.
Countries need to spend time and resources finding the epicentres and learning how the diseases spread.
For example, when the H1N1 influenza pandemic broke out in 2009, the world's eyes were on South-east Asia. But, the outbreak started in North America and the bug swiftly spread to Mexico and other parts of the world.
While disease surveillance, public health education and pandemic preparedness are vital, it is important to understand the enemy - be it a naturally occurring virus or a man-made one, he says.
Get a copy of The Straits Times or go to straitstimes.com for more stories.