Ronald DeRozier invented the vaccine. We're of course very exhilarated and we quite naturally have these dreams of future success, but this is going to be a vaccine that can save the world. Robert Gallo is co-discoverer of the virus that causes AIDS. He thinks DeRozier's vaccine is too risky. If it's not sufficiently crippled and it replicates significantly the dangers it may cause disease in the person who got the vaccine and it may spread to other people who didn't get the vaccine. DeRozier, a soft-spoken 46-year-old microbiologist, realizes the risk, but everything else he hurled at AIDS fails. We tried a variety of vaccine approaches, including inactivated whole virus, subunit vaccines, recombinant viral vectors, and what we found was failure, failure, failure.

Frustration led him to the most powerful weapon in the vaccine arsenal, the live virus itself. In our case what we've done is delete genes, take whole genes and remove them from the virus, so that it's able to reproduce itself, but it is very weakened in its ability to do so. The weakened virus is injected into his experimental monkeys. It's just strong enough to trigger the immune system into making antibodies without causing disease. The antibodies are ready for action when the monkeys are later injected with a full-strength virus. So far, the antibodies have destroyed the invaders. It's the same classic approach used to prevent polio, smallpox, and measles. But AIDS is a far more dangerous enemy. It's the only virus that directly attacks the immune system, the very cells that are supposed to fight disease. And it mutates faster than any known virus, spewing out thousands of new attacking particles, each different, further confusing the body's defense system.

It's a chronic, long-term, lingering infection that goes on for months and years for which the immune response is ultimately ineffective. The host loses and the virus wins. DeRozier's monkey experiments show the virus doesn't have to win, but the promise could be fraught with peril if a live-age vaccine is used in humans. Even a crippled virus might be powerful enough to defeat the immune system many years later. What if this produced AIDS in 80% of people in 12 years? It works slower.

Are we sure that a crippled virus won't eventually cause AIDS? I'm far from sure of that. We can continue to do all the monkey experiments till we're blue in the face and we're still not going to get the real answer. The real answer is going to come from people. The real question to think about is would you do this to your own child? In my lifestyle or my daughter's lifestyle no I would not. There's no guarantees that this is going to be safe long term. If I was in uh my lifestyle was different and I was at extremely high risk and was either unwilling or unable to remove myself from that risk, I would take the vaccine in a minute. People in the world's most infected regions, Asia, Africa, may never get the choice.

It's politically explosive to test the vaccine in developing countries without first trying it in the U.S., and that's not likely to happen soon. If I were the person who had the power to allow it or not allow it, I wouldn't. Not at this stage. I think everyone needs to look at this approach more seriously, the scientific community, and decide what do we need to know, what more experiments would we need to do to say, okay, we've got enough information to go ahead and people. More than a dozen safer, but less powerful vaccines are already being tested in people, but many consider them too weak to be effective. And if those fail, then there may be more of a willingness to look at the riskier approach.

Many more ifs await the controversial vaccine. If it passes all tests, it would likely be a quarter of a century before available for general use. Even Ronald DeRozier tempers his hopes. I think it's possible that we may never have a successful vaccine, an effective vaccine. But I hope that that's not true. That keeps me going, that we keep trying. Meanwhile, up to 10,000 people a day are infected with the seemingly unstoppable virus that causes AIDS. CNN Presents the Weekly News Magazine continues now with the Apocalypse Bug. Once again, here's Judy Woodruff. The killer virus known as Ebola has been shrouded in mystery since it was first identified nearly twenty years ago.

It kills eight out of every ten people it infects. There is no known cure. Larry Lamont visited ground zero of last year's Ebola outbreak in Zaire. Since then, scientists have discovered some frightening new facts about the virus. Ebola is a complicated virus. It looks a little bit like a question mark. Ah! Ebola is a question mark, even though much has been learned about it. While other diseases kill more people, Ebola grabs the headlines because of the way it kills.

Attention! It has the ability to destroy the integrity of your blood capillaries. The result is that they leak fluids. The watery, reddish stuff in your blood bleeds out from every orifice, from your nose, your eyes, from all over your body, your ears, and eventually actually from the skin itself. I've done lots of outbreaks during my lifetime, but not a disease that strikes so fast, kills so many in such a short period of time. In 1995, scientists from around the globe tried to turn tragedy into opportunity. They rushed to the scenes of two Ebola outbreaks in Africa, hoping to learn where the virus comes from, how it spreads, and if it can be stopped.

Much of the interest in Ebola is based on fear. AIDS showed the world the dangers that lurk here in the rainforest, and new books and movies have spread the word about other emerging viruses. The people of the world want them contained here. Here is Central Africa, where Ebola was first identified in 1976. It started in a mission hospital in the village of Yambuku Zaire, and quickly spread to 55 villages along the region's largest river, the Ebola River. Back then, Dr. David Heyman was in his early 20s, a new hire at the Centers for Disease Control. After helping solve the riddle of Lechon Air's disease in Philadelphia, he was dispatched to investigate the mysterious African outbreak.

We did know that it was very dangerous and that people were dying. We had seen in Kinshasa one of the missionary sisters who had been evacuated from Yambuku to Kinshasa who died a very terrible death. And so it's a very frightening disease. Some called it an Androvida strain. Special plans were devised for those daring enough to go to Yambuku. We made an arrangement with NASA to collect one of the isolation chambers that they had put the astronauts in after returning from the moon and activated that so if there were any people who became sick in Yambuco, we could put people in this isolation unit and take care of them in the U.S. But they never needed it. As quickly as the sickness appeared, it disappeared.

The doctors did learn what caused it to spread so quickly. Nuns at a mission hospital unwittingly used the same infected syringe on hundreds of people. By the time the disease had run its course in 1976, more than 400 were dead. Samples of the killer virus were brought back to the Centers for Disease Control in Atlanta, Georgia to be studied until the next outbreak. Nothing had been heard from Ebola since then, and I believe that we were going to hear from it sooner or later. It was just a question of time before it cropped up again and a question of how bad it would be when it did crop up. Ebola did reappear, 13 years later, in the most unexpected place, Reston, Virginia, just outside Washington, D.C.

In October 1989, research monkeys imported to this former primate center in a residential neighborhood began to die. Shocked researchers determined it was Ebola, never before seen in the United States. Worse, it looked like this particular strain was being transmitted through the air, like the common cold. What scares me about Ebola is that clearly the virus has the potential to go airborne, and if somehow that were to be linked up with its virulence potential, you would have a virus with a very high morbidity and mortality, with the infectiousness of influenza.

Fearing the virus might spread to the surrounding community, the Primate Center called in the U.S. military. They killed every single monkey in the building, more than 400, and sanitized and sealed the site. General Philip Russell authorized the mission. It scared me very much. It certainly did. And if it came again, it'd still scare me. I think we ducked a bullet that time. Ducked a bullet because four workers who contracted the virus never got sick. Ebola Reston, as the new strain came to be called, turned out to be harmless to human beings. Since then, this strain of Ebola has turned up four more times at primate centers in the United States, most recently in Alice, Texas. And the story of the Reston outbreak has been popularized in Richard Preston's best-selling book, The Hot Zone.

Your talent is being quarantined. But it wasn't until the summer of 1995, coincidentally as the movie Outbreak was playing in U.S. theaters, 48 hours, that the world once again heard from the strain of Ebola that kills humans, Ebola Zaire, an African boomtown, home to more than 200,000 people. Once again, Dr. David Heyman was one of the first Western scientists on the scene. He immediately realized the hospital was helping spread the virus. Ebola patients weren't quarantined. Many of them lay in their own contaminated blood. We walked back to the patient isolation ward with protective clothing and in the wards the patients who had remained at the hospital were in very late stage of disease with bleeding they were probably not conscious most of them. There were some persons who were dead lying on other beds and and there was a general state of poor sanitation. Once again, caregivers, doctors, nurses, nuns, were wiped out early in the epidemic. At one point, 24-year-old Dr. Boaka was the only physician treating Ebola patients. Apart from a few nurses, everyone else had fled.

I found the courage to volunteer because most of the people who were sick at first were doctors and hospital personnel. I wanted to help these people. They were my colleagues. We worked for four or five days without disinfectant, four or five days without protection. Soon, Western doctors and aid agencies provided that protection. Gowns, masks, and plenty of virus-killing bleach. The sanitary measures worked. Slowly but surely, the virus was stopped. Once again Ebola disappeared into the rainforest, leaving behind a trail of misery. More than 180 people died in this hospital ward alone, but there are some survivors. From them may come clues that could help solve the Ebola mystery. The clues were in the blood of those who lived. Zairean doctors theorized they contained antibodies to Ebola. So they transfused blood from the survivors into eight dying patients. Seven lived.

She had a headache and a neck ache, and she was in a coma. She didn't move, and we gave her a transfusion the 23rd of June until the 1st of July. Only July 1st, she woke up. Some of the others who received the blood serum were out of their beds and days. Western scientists still aren't sure if the transfusions are responsible for the recoveries. They point out another possibility. Ebola sometimes seems to burn itself out, weakening as it passes from person to person. Since the epidemic, researchers at the United States two premier virology labs have made some terrifying discoveries. Discoveries indicating Ebola may be even more dangerous than originally thought. At the CDC, scientists found large quantities of the virus on victims' skin and sweat glands. It means Ebola might spread through simple human touch.

Even more frightening, Ebola Zaire can be transmitted through the air. At the U.S. Army Medical Research Labs in Maryland, caged healthy monkeys like these contracted the kequit strain of Ebola from monkeys clear across the room. But those discoveries are just sideshows to the main mystery. Where in the rainforest is Ebola hiding? What animal is carrying it harmlessly right now and periodically transmitting it to man? If we want to find this mysterious virus wherever it lurks in between epidemics, this is the time to do it. Near Kikwit, researchers tried to get answers. They tracked tens of thousands of animals, rodents, birds, insects, anything they could catch and tested them for Ebola.

They focused their search on this tract of rainforest where the first victim, a charcoal maker, worked every day. So far, none of the samples has turned up positive. The animal host, or carrier of the virus, remains a mystery. Just a couple of samples in here. Certainly there's no extraterrestrial forces dropping these things on us. It's just that man is coming into contact with an environment where he had very little been before. Ah! The virus has retreated, for now, but it left behind a powerful message. Man's steady invasion of once pristine ecosystems carries a steep price tag.

Exposure to new deadly diseases that can spread anywhere in the world. The outbreaks are in effect, the revenge of the rainforest. Spread has a close now with the apocalypse side, once again, Judy Woodruff. Twenty years ago, no one had ever heard of Legionnaire's disease, Ebola, or AIDS. The threat from drug-resistant strains of staph, strep, and tuberculosis was minimal. Today, though, the threat of a worldwide epidemic, even an Apocalypse Bug, is real. Are we prepared? Once again, Larry Lamont. We don't know what's wrong with the patient. The patient's a learning constant. We did again. These U.S. soldiers are a special breed of paramedics.

Okay, you're going to need to lie down on your back. And you get in. Their ambulance is a cargo plane. Lift! Their patients, infected with deadly contagious disease. This was a practice drill in West Virginia. In a real outbreak, they would load contagious patients into sealed stretchers for evacuation. A lucky patient rushed to treatment may be stabilized and might survive. There are only a few containment stretchers, not enough for an epidemic, so time is critical. Majority.

With global transportation, deadly bugs that emerge from remote areas can hop a jet to New York, London, Tokyo, and spread. And health workers will not be prepared. The world hasn't learned the basic lesson of the epidemic is that an emerging problem somewhere can become a crisis here or there or everywhere within a relatively short period of time. The early warning system for tropical disease is a network of 35 labs that report to the World Health Organization. But the system is weak. At least 28 people died in Kenya before doctors realized the cause. Yellow fever, a mosquito-borne virus that causes vomiting, liver failure, and eternal bleeding. For six months, they thought it was malaria. The teaching in the medical school itself, because they don't see the disease, is minimal. So the know-how in the field to suspect and in the lab to be able to make a diagnosis is not there.

And I think this is what we're suffering from with some of these diseases. They will strike us because we're not prepared. This is of great concern to us and unfortunately that laboratory is not unique in that part of the world. When the World Health Organization labs were surveyed, the gaps were obvious. Only 56% had the ability to diagnose yellow fever. Fewer than half could spot Japanese encephalitis, hantaviruses, and Rift Valley fever. All killers. I think that on a global basis, there virtually is no significant surveillance efforts. Dr. Oye Walechamari has tried and failed.

He used to direct a lab in Nigeria, stockpiling frozen samples of blood and tissue to study new diseases. But his life's work was destroyed when a political crisis in Nigeria led to the shutdown of the nation's power plants. The worst situation that has occurred to us has been when the power failure comes. You don't have water supply. And samples you've collected all your life, destroyed. He had hoped his work would save lives because the samples could be used to monitor the spread of new diseases.

What did you lose? I tell you everything I've collected in the last 20 years. Blood samples? Yeah. Tissue samples? Yes. From animals? From animals, from human beings, you know. To study which disease? Yellow fever, lacerative fever, even polio, some of those other diseases.

Can you recover that material? Come forever. Even the Centers for Disease Control, United States foremost public health lab, has been dangerously close to a breakdown. The special pathogens branch where scientists studied the most hazardous germs on the planet was understaffed. The victim of a federal hiring freeze. Memos obtained by CNN presents under the Freedom of Information Act show that for months the lab director Dr. CJ Peters was warning his bosses of danger. March 1994. I cannot tell you we will be able to respond to the workload we have now, nor that we can be confident in the quality of the work output.

June 94. We need to talk soon about this problem. There are a lot of issues, including safety. A month later, July 1994. We would be unable to respond to any significant U.S. disease introduction. The country has a whole variety of priorities. People are killed in accidents, they're killed by violence, and they may be killed by a virus like this. And I think that our, we can't prioritize that in special pathogens branch, we can't prioritize that for the country. But I think that I'd have to stand by what I said, that we are stretched to the breaking point. Even when the hiring freeze was lifted, it took months to fill vacant positions. Washington's budget act still hangs over the agency. We have to think about it, I believe, like an insurance policy. You may never need it, you may not require it, but if you do need it, it's going to be very important to obtain the insurance before it's too late.

Meanwhile, many of the forces that help the disease emerge and spread are as strong as ever. International jet travel and destruction of the Great Rainforest, where deadly mystery bugs live and in the past, quietly died. It's germ warfare, and the germs seem to be winning. So it was your brother who referred you to America....continues now with the Apocalypse Drive. Once again, Judy Woodruff. AIDS and Ebola have alerted us to the terrifying threat of mysterious viruses we are helpless to combat. The rainforest contains thousands of other viral bugs, some we barely understand. Others we've never even seen. Some may turn out to be beneficial. After all, penicillin came from a mold. But others may be even more insidious, more contagious than anything we know now. The battle to stop them will be as intense as any fight between the forces of good and evil prophesied in the writings of old. In the end, the enemy could be an apocalypse bug. Now for a look at what's ahead on the next CNN Presents.