The HIV/AIDS epidemic has outstripped even the worst predictions, surprising experts with the speed at which it has infected 36 million people, the UN said.

More than five million new cases were reported this year alone, according to new figures from the UN agency that spearheads the global battle against AIDS--UNAIDS.

"It has killed more people this year than any other year before," said Dr. Peter Piot, the executive director of UNAIDS.

HIV/AIDS has claimed three million lives in the past year and 21 million since the start of the epidemic two decades ago, UNAIDS said in its latest report.

The agency said cases of the HIV virus and AIDS were 50 percent higher than experts had forecast a decade ago, despite advances in both treatment and prevention.

"The world clearly underestimated how rampant this epidemic would become," said Dr. Piot. "We've got far more cases than the worst-case scenario thought out 10 years ago. It is the number one cause of deaths in many, many parts of the world."

In Africa, the worst-hit region, infection rates have fallen slightly, but only because so many people have already been struck down. A million more people in sub-Saharan Africa were infected this year, bringing the total in the region to 25.3 million. In some African nations, one in three adults has the virus.

"The AIDS situation in Africa is catastrophic," said Dr. Piot. "One of the greatest causes for concern is that, over the next few years, the epidemic is bound to get worse before it gets better."

UNAIDS estimates that $3 billion, which is only a fraction of the $52 billion spent annually in the US on obesity, could turn the situation around.

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Hundreds have died of the ebola virus in Uganda in the recent months. Few people who've been infected with the Ebola virus have lived to tell the tale. For every three who survive an outbreak, there can be up to another seven who end up dead from it. There is no cure for Ebola and the only treatment is to try to keep the body comfortable.

The symptoms begin with headaches, fever, muscle pains, fatigue and diarrhea. They can take days or even weeks to appear after the initial infection, which usually occurs by close contact with another infected person. Within a week, sometimes days, the patient goes rapidly downhill.

Richard Preston, author of The Hot Zone, a best-selling book on Ebola outbreaks, describes in lurid detail how the virus begins to digest the inner fabric of the body. "Literally every opening in the body bleeds, no matter how small," he writes.

The Ebola virus is named after the Ebola river in Zaire, now the Democratic Republic of the Congo, where the first known outbreak was recorded in 1976.

People who come into contact with the body fluids of an infected person run an exceptionally high risk of becoming infected, which is why family members and healthcare workers are often among the victims of an outbreak.

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Throughout France, the public is in an increasing panic about the spread of mad cow disease. It is a frenzy based more on fear than fact, because the number of cases in France remains minuscule compared with the epidemic that hit Britain a few years ago. Still, that has not stopped dozens of school districts from eliminating beef in their cafeterias. Some of the country's top chefs are debating whether to keep beef on their menus. And some countries, reacting to France's panic, are refusing to purchase the beef. So far the Czech Republic, Italy, Austria, Spain, the Netherlands, Poland, Hungary and Russia have joined the embargo on French beef.

"We have never seen anything like this before," said Jean-Yves Jouveau, the director of a slaughterhouse in Limoges, at the center of a region that specializes in raising cattle for beef. … "The country is locked now into this collective fear, and no matter what, it will take a long time to recover."

The number of reported cases of the disease has been rising steadily in France this year. The real panic in France set in three weeks ago after a farmer was arrested for trying to sell a diseased cow for slaughter. The authorities were able to intercept the cow, but not before thousands of pounds of suspect meat from the same herd had been sold.

Coverage of the arrest only seemed to encourage what the French are calling a "psychose"--a hysterical fear. Television stations broadcast lengthy documentaries on the human form of the disease, called Creutzfeldt-Jakob. When one program featured some particularly emotional footage of a British girl paralyzed by the incurable disease that destroys the brain, the national anxiety seemed to skyrocket. Many consumers began avoiding beef entirely.

The French public has some reason not to trust the authorities, who have had a poor track record of keeping the public informed about health dangers.

In the 1980's, the government was caught distributing blood tainted with the virus that causes AIDS. Courtroom testimony later showed that officials knew about the contamination, were aware of methods to clean the blood, and yet took no action while thousands of patients were infected with H.I.V.

In that case, the French heard that with millions of dollars at stake some government officials preferred to keep quiet. So last week, many French citizens wondered out loud if this was happening again, in an effort to protect France's huge cattle industry.

Many passengers flying out of Africa are familiar with the ritual: the doors close and the flight attendants ask those wearing contact lenses to shut their eyes. Some passengers pull blankets over their heads. Then the crew pop the tops on two cans of a sickly sweet aerosol and walk quickly down the aisles, a white cloud billowing behind them.

This is mosquito control at the nexus between the poor, infected world and the rich, scared one. The spray is meant to kill any bugs that slipped in while the doors were open; a long-lasting fumigant is used in the luggage hold.

There are 3,500 species of mosquitoes in this world; some even suck plants. Luckily for mankind, only a few relish human blood.

In the New York area, the arrival of the West Nile virus last year brought home just how unpleasant an unlucky series of coincidences can be when the right mosquito for the job is around; of the 62 cases last year, 7 were fatal. Seven cases have been reported this year.

Most mosquitoes don't fly five miles in their lives, but a few have joined the jet age. Just last month the World Health Organization in Geneva issued a warning about "airport malaria."

France leads the world, with 26 cases since 1970, a few of them fatal, among people who had never visited a malarious country but who lived near airports or worked at them. They were probably bitten by stowaways disembarking from flights from West Africa.

"These are the dangers of globalization," said Dr. David L. Heymann, director for communicable diseases at the World Health Organization, although he was quick to point out that humans carry disease around the globe more effectively than mosquitoes do.

Malaria is the most common disease carried, but not the only one. Besides West Nile virus and its relatives, yellow fever, dengue fever and elephantiasis can all be injected by mosquito saliva.

Not all that faint humming in the global village is from Internet connections.

A 66-year-old woman was recovering from a heart bypass in a hospital near Detroit when she suddenly developed respiratory failure and a serious infection. Doctors quickly gave her an antibiotic that usually works. This time, however, it didn't. The bacteria causing the woman's infection were resistant to the drug.

The woman's doctors immediately turned to a newly approved antibiotic, a powerful one designed specifically to attack the kind of dangerous antibiotic-resistant microbes that had infected her.

But her physicians were dismayed to find that drug didn't work either--the bacteria in her body were resistant to it as well. The woman died soon after.

Cases like this around the country have caused rising alarm among doctors and public health experts. They are also at the center of an increasingly acrimonious dispute over how antibiotics are used in the U.S.--specifically, how farmers use them to promote the growth of livestock.

Experts have long known that the overuse of antibiotics by doctors and their patients has reduced the ability of those drugs to cure infections. Now there is mounting evidence that the antibiotics widely used on farm animals are also diminishing the power of important antibiotics to help people.

Giving animals antibiotics in their feed can cause microbes in the livestock to become resistant to the drugs. People can then become infected with the resistant bacteria by eating or handling meat contaminated with the pathogens.

Following are key facts and figures about the disease that has killed 18.8 million people since the beginning of the epidemic.

• AIDS (Acquired Immune Deficiency Syndrome) was first reported in 1981 among homosexual men in the United States. The human immunodeficiency virus (HIV) that causes AIDS was identified by 1983.
• AIDS is the fourth leading global cause of death, according to UNAIDS.
• In Africa, AIDS now kills 2 million people a year--10 times more than war.
• At the end of 1999, 34.3 million adults and children worldwide were living with HIV/AIDS. More than five million people are newly infected each year.
• 24.5 million people are living with the disease in sub-Saharan Africa, 5.6 million in South/Southeast Asia, 1.3 million in Latin America, 900,000 in North America and 520,000 in western Europe.
• There are now 16 countries in which more than one-tenth of the adult population aged 15-49 is infected with HIV. In seven countries, all in the southern cone of the African continent, at least one adult in five is living with the virus.
• So far, the AIDS epidemic has left behind 13.2 million orphans--children 15 years old or younger who have lost one or both parents to the disease.
• At least one of every two 15-year-old boys in Kenya, South Africa, Zimbabwe and Botswana is on track to die of AIDS.
• With a total of 4.2 million infected people, South Africa has the largest number of people living with HIV/AIDS in the world.
• In Botswana, 35.8 percent of adults are now infected with HIV.
• AIDS has sharply reduced life expectancy in many African countries. For instance, it is now 39 in Botswana, instead of 71, as it would have been without the disease.

AIDS is a syndrome, a combination of illnesses. The HIV virus attacks the immune system and leaves the body vulnerable to a variety of life-threatening diseases, so-called opportunistic infections, such as tuberculosis.