On May 20 1983, in a paper published in the US journal Science, a team from France's Pasteur Institute, led by Luc Montagnier, described a suspect virus found in a patient who had died of AIDS.

Montagnier's ground-breaking work led to the determination by US researcher Robert Gallo that the virus was indeed the cause of acquired immune deficiency syndrome (AIDS).

At last, a key had been found to understanding the mysterious immune-ravaging disease - the "gay plague" as British tabloids smugly called it - which had surfaced among American homosexuals two years earlier.

It took another three years to resolve a spat over the pair's rival claims to be first to discover the AIDS virus, enabling the duo to share equally in the glory.

The mood was upbeat.

Never had a new, killer pathogen been identified so quickly.

Stoked by the success of antibiotics and the polio vaccine, optimism was brimming that this threat would now be stopped in its tracks.

"Today's discovery represents the triumph of science over a dreaded disease," the then US health secretary Margaret Heckler declared, when Gallo staked his claim on the virus discovery in April 1984.

"We hope to have a vaccine ready for testing in about two years."

Few promises have been so tragically premature.

When Heckler uttered those words, the tally of known cases of AIDS was less than 3 000.

SETBACKS AND BREAKTHROUGHS Today, the number stands at 25 million dead, heterosexual and homosexual alike, and another 33 million infected.

The scale of human misery, though, is incalculable.

A ragged army of more than 11 million children have lost one or both parents to the disease.

"In the field of AIDS, a huge number of mistakes have been made over the past 25 years," sighs a leading French researcher, Olivier Schwartz.

On the plus side, the men and women in lab coats made good headway against HIV.

They provided an arsenal of drugs that, with the advent of the triple "cocktail" of anti-retrovirals in the mid-1990s, have helped turn HIV from a death sentence to a manageable disease.

But there is still no vaccine, for the virus has turned out to be an unimaginably slippery, mutating foe - quite possibly the most elusive pathogen to have emerged in human history.

Attempts to make an HIV-thwarting vaginal gel, or microbicide, have been similarly frustrating.

Thus, in the 21st century, the main shield against HIV is the rubber condom, invented in the 19th century - or sexual abstention, which is timeless.

Then there was catastrophic delay, among politicians, policymakers, religious leaders and the public too, about rooting out the taboo, stigma, myth and complacency in which AIDS proliferates.

This work still remains dangerously incomplete.

In China, India and the countries of the former Soviet Union, the peril remains of the virus leaping from niches of infection among drug users, homosexuals and prostitutes to a mainstream epidemic.

Even more culpable was the horrific wait, of nearly a decade, before anti-retrovirals started to fall sharply in price and become available to sub-Saharan Africa, where two-thirds of people with HIV or AIDS live.

Price is no longer the big problem.

Political denial and lack of infrastructure to distribute the precious drugs are.

"In Africa, not even 10 per cent of the people who need treatment are getting it," says Schwartz, noting that for every person in low- or mid-income countries who began receiving anti-retrovirals in 2006, six new people became infected.

The UN Millennium Goals and G8 pledges testify that political commitment on AIDS is strong and that the world is now aware that novel infectious diseases are everyone's problem.

No country, however strong or secure its borders, is secure.

Billions of dollars are being marshalled by the Global Fund, and the United States, under President George W.

Bush, has boosted its spending on AIDS emphatically.

But to meet the goal of universal access to AIDS treatment and care by 2010 would require a quadrupling of funds to an estimated 42 billion dollars annually, if overhauling healthcare systems is included, according to some estimates.

Today, the terror of AIDS that prevailed 25 years ago has disappeared - but so has the burning optimism.

"I would have preferred to celebrate the anniversary of the end of the epidemic than of the publication" of the isolation of the virus, Montagnier told AFP.

Lars Kallings, a Swedish microbiologist who is the founding president of the International AIDS Society, gives a bleak assessment: "HIV-AIDS may never disappear from mankind."

Nampa-AFP

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