"Don't watch this week's installment of 'Frontline' if you want to sleep well tonight. 'Plague War' is an unsettling look at how biological warfare could (or might, or will) devastate the world...

The Ebola and Marburg viruses have received more press, but smallpox, it turns out, is an even greater threat. Smallpox killed more people in the 20th century than all the world wars combined; in the 1970s, the World Health Organization declared it eradicated--meaning that vaccinations were discontinued.

Now, almost no one has immunity. And guess what biological agent was once heavily stockpiled in Russia and may still be hidden there in large quantities? What if an out-of-work Russian scientist opted to sell some to a terrorist group or to a rogue nation? Eek!

'Plague War," including graphic photos of the progression of smallpox in a human being, isn't for the faint of stomach or heart. But it's effectively thought-provoking."

"...this chronicle revealing Soviet violations of the 1972 treaty outlawing [biological] weapons, is no ordinary hair-raiser. Extraordinary in its detail, it reveals how vast a development program the Soviets engaged in. We learn how one Soviet researcher working on a virus akin to Ebola is accidentally infected, and how, after his agonizing death, scientists husbanded his body fluids so the virus could be replicated in more potent forms. The new virus would be christened "Variant U" in honor of the dead scientist, Nikolai Ustinov. We are instructed, as well, in the Soviets' determined efforts to block inspection of their plant sites, Dr. Alibekov--who would in time defect--was indeed astonished to learn, during his inspection tour of U.S. sites, that the Americans had all along been abiding by the treaty. How quaint that must have seemed, to the Soviet inspectors."

PBS' 'Frontline,' as it always seems to do, is proving once again that what you don't know eventually could hurt you.

'Plague War' is a piercing bell toll about the potential threat of world biological terrorism...'Plague War' ventures well beyond the terrorist movement to document years of research in the former Soviet Union for biological weapons that could have been delivered via strategic missiles.

An extensive interview with Ken Alibek, the defector and top official in the Soviet program, reveals an intricate, secret system of research in Siberia, what is now St. Petersburg and other places, resulting in new--and ever more virulent--weapons.

Anthrax was 'grown by the ton,' one expert says, adding the Soviets had 'thousands of scientists and engineers' devoted to the project. It was 'so massive and had such capacity it was unimaginable,' he says. 'They had really thought about using these weapons and how to use them and their effects.'

His comrades, Alibek says, never developed biological weapons for the battlefield. It was 'for use against civilians. New York. Los Angeles. Chicago....'"

"The chilling reality of potential biological warfare and terrorism is uncorked in 'Frontline: Plague War,' and yes, it's just as scary and intimidating a scenario as we'd suspected. Pictures of human faces turned inhuman by the effects of disease make this particularly unsettling.

But in terms of presentation, it's a standard style of documentary that loses steam fairly quickly as it probes for long, long minutes on the Soviet violation of biological weapon stockpiling. Maybe the viewer has to tune out because the reality is so objectionable in this age of potential global destruction."

"'Frontline' delivers a dire report on suspicions of the existence of stockpiles of smallpox, plague and anthrax viruses. All are said to be readily convertible to offensive biological warfare, with lethal potential. Two pounds of powdered anthrax efficiently deployed, one researcher notes, would be enough to kill hundreds of thousands of New Yorkers.

'Plague War' raises doubts about the enforcement of international agreements banning biological weapons. Intelligence experts warn that some former Soviet colonels and generals may still be working at developing them, either for Russia or for terrorist-prone clients. Coming immediately after 'Nova," this horror is enough to make El NiŅo benign."