Biohazard

To be sure, we had already achieved global dominance in this field by the 1980s, when we could launch a biological attack with intercontinental ballistic missiles on targets thousands of miles away. But Stepnogorsk demonstrated our ability to wage biological warfare on a scale matched by no other nation in history. We had taken the science of biowarfare further in the previous four years than it had traveled in the four decades since World War II.

Needless to say, we didn't advertise our accomplishment. The accident at Sverdlovsk had briefly opened a window on our biological warfare program to the outside world, but since then our secrets had stayed well hidden. The international community still knew nothing of Biopreparat, and it had no reason to suspect our program's growing dimensions.

Smallpox

Moscow, 1987

The word virus comes from the Latin term for poison. Viruses are invisible under most microscopes and hundreds of thou sands of times smaller than a grain of sand. Their existence was unsuspected until Dmitry Ivanovsky, a Russian microbiologist, discovered them in the late nineteenth century while investigating an outbreak of mosaic disease in tobacco plants. Ivanovsky found

that the mysterious agent responsible for this disease was able to pass through filters that otherwise blocked bacteria. Over half a century would pass before the first virus was seen and identified under an electron microscope, but Ivanovsky's discovery launched a new field of research into infectious diseases.

As more viruses were discovered, scientists grew increasingly baffled by their behavior. Viruses seem to exist on the threshold of

life, remaining inert until they fasten onto the cells of other organisms. They are structurally simpler than bacteria, consisting only of a protein shell, a sequence of DNA or RNA, and sometimes a lipid membrane, but they are capable of annihilating the most sophisticated biological system. Not all viruses kill their hosts — to do so is in many ways impractical — but when they do, they often combine incredible virulence with a high degree of contagiousness. A virus is programmed for its own procreation, but it cannot do this alone. First it must locate a host with the cell structure and nutrients necessary for it to reproduce. Viruses come to life inside the nucleus or cytoplasm of their host cells, fusing with them and ultimately hijacking their functions.

The human body commands a number of complex mechanisms for resisting, containing, and killing pathogenic microorganisms. The immune system works on many levels at once, like an army with scouts and infantrymen, naval and air power, a sophisticated information network, and a carefully delineated command structure. Some cells are responsible for surveillance, others for coordinating information; some focus on local maneuvers while still others direct more general attacks. Immunologists distinguish between specific and nonspecific immunological reactions. Specific or acquired immune responses depend on memory cells, which store information about previous invaders and thus play a significant role in conferring immunity.

Among the most important agents in the immune system are T cells. They act as scouts, circulating through the bloodstream and moving into lymph nodes, on the lookout for foreign substances. As soon as a virus enters the bloodstream and infects its first cell, it will be recognized by T cells, which immediately activate, replicating themselves and sending out signals, calling for the formation of antibodies and attracting them to the site of infection. Antibodies are like ground troops. They are particularly effective at attacking viruses and bacteria that are still coursing through the system, before they have infiltrated target cells.

Within seconds of infection, defensive proteins and inflammatory agents are released, which activate natural killer cells and lead them to the site of infection. Interferon, one of the most powerful antiviral agents, degrades viral RNA, slows down protein synthesis, and inhibits viral reproduction in infected cells.

By the end of the first week or the beginning of the second, tin-body will in many cases have developed virus-specific antibodies, which sometimes seek to neutralize the virus by binding to its sin face and preventing it from penetrating into new cells. But viruses are adept and mutate quickly. Countless are now capable of inhibiting and neutralizing the body's natural defenses, rendering their resistance ineffective.