National Geographic : 2002 Feb
1i + eI! First large-scale human trial of an AIDS vaccine begins with 5,400 North American and European volunteers. SOURCE:UN M NATIONALGEOGRAPHIC MAPS team that contributed to the discovery of HIV in 1984. But we still don't understand exactly how the virus causes disease. HIV seems full of contradictions. It can tar overwhelm the human immune system, yet the virus itself is fragile. Cold viruses linger on 1ill, hands, and sometimes for days on doorknobs, hi but fresh air dries and destabilizes HIV in Q' hours or even minutes. Contact with rubbing alcohol or chlorinated water quickly renders it inactive. Simple bar soap neutralizes HIV by breaking the chemical bonds of its lipids, or fats. And because so few cases of oral transmis sion have been documented, doctors conclude that the same antiviral compounds in saliva and stomach acids that protect us from a host of germs prove very effective against HIV in low concentrations. Once a person is infected with HIV, how ever, the virus attacks the very immune cells, called T cells, meant to fight it. "Think about trying to invade a fortress," said Gary Nabel, director of NIH's Vaccine Research Center. "Would you start by setting off a grenade in front? No. You would sneak in quietly, pen etrate the nucleus, and sit there. You'd clone Yourself. You'd make lots of copies. Then, when an opportune occasion came along, when there was a lot of commotion and people were dis tracted, you'd say, 'Boom! Here I go. "That's what HIV does. That's what has allowed it to become so successful from its per spective and so tragic from ours," said Nabel. During a period of typically eight to ten years HIV lurks in the body, mutating rapidly and thus avoiding recognition. It reproduces mas sively, and waits. Finally, at the introduction of a disease that an unimpaired immune sys tem would normally control-tuberculosis or pneumonia, for example-the immune system is overcome by HIV so that it cannot fight, and the disease kills. it INETEEN NINETY-SIX was the year the thunder came," Igor Ivanov said, and "the Russians heard it, and they crossed themselves." Ivanov, a doctor at the Kaliningrad Regional Infectional Hospital, was referring to the year SHIV cut loose in Russia amid the chaos of a collapsing economy. Unemployment shot up, and with it alcoholism and crime. Drug dealers began to create a heroin market in Russia.