Progress and setbacks in Aids battle:

It is hard to believe that the world has been living with the Aids epidemic for a quarter of a century.

As 20,000 delegates meet in Mexico City for the 17th International Aids Conference, there is much progress to report, but some setbacks, too.

New figures from the United Nations show that, for the second year running, the overall number of people who are HIV-positive has dropped, from around 33.2 million in 2006 to 33 million last year.

The figure is going in the right direction, but that is still the equivalent of the entire population of Canada being infected.

The number of Aids-related deaths has also fallen slightly, from 2.1 million in 2006 to two million last year.

Good and bad

There is good news, too, on funding. President Bush has just secured approval from the US Congress to triple his budget to fight Aids and other diseases in Africa and the Caribbean.

Over the next five years $48bn (£24bn) will be spent, up from $15bn. The US will also sever the link between the money and policies of abstinence.

There will also be an end to the ban on people with HIV entering America.

Yet with the good news comes bad. In some countries, rates of infection continue to increase.

They include China, Russia and, surprisingly, Germany, Britain and Australia.

Then there are the children: 370,000 new infections last year.

It is hard to believe that the world has been living with the Aids epidemic for a quarter of a century.

As 20,000 delegates meet in Mexico City for the 17th International Aids Conference, there is much progress to report, but some setbacks, too.

New figures from the United Nations show that, for the second year running, the overall number of people who are HIV-positive has dropped, from around 33.2 million in 2006 to 33 million last year.

The figure is going in the right direction, but that is still the equivalent of the entire population of Canada being infected.

The number of Aids-related deaths has also fallen slightly, from 2.1 million in 2006 to two million last year.

Good and bad

There is good news, too, on funding. President Bush has just secured approval from the US Congress to triple his budget to fight Aids and other diseases in Africa and the Caribbean.

Over the next five years $48bn (£24bn) will be spent, up from $15bn. The US will also sever the link between the money and policies of abstinence.

There will also be an end to the ban on people with HIV entering America.

Yet with the good news comes bad. In some countries, rates of infection continue to increase.

They include China, Russia and, surprisingly, Germany, Britain and Australia.

Then there are the children: 370,000 new infections last year.

She is mother to a number of children, but only the oldest ones know she is HIV positive.

So, too, does her husband, Luis - again, not his real name, because he is also infected.

Idalia says she cannot tell her wider family, neighbours or friends.

"It is very difficult in a small place like this," she says.

To try to ease the suffocating pressures of isolation, Idalia agreed to join an experiment.

She and eight other people with HIV living in surrounding villages linked up to a new mobile phone system.

Set up by a British consultancy firm, SHM, the project is called Zumbido, which means buzz in Spanish.

Using specially adapted cellphone technology, each of the people in the group can send a message simultaneously to all the others. They can also hold a group conference call.

The aim was to form a bond of friendship, a network of shared advice, between people living in silent solitude.

In the first month of its operation, Idalia's group and three others sent 80,000 text messages to each other.

"The phones helped me with my depression," says Idalia. "I felt companionship. We became a family where we could share and where there was no fear of rejection of isolation."

Laws ignored

Some regard the Aids prejudice as nothing less than a violation of human rights.

Last month, a coalition of 400 Aids and human rights organisations called on governments to end what it called the "abuses fuelling the spread of HIV".

The group spoke of practice not matching legislation. In other words, laws were being ignored, especially when it came to sex workers and drug addicts.

"It is a tragic irony that those at highest risk of HIV often receive the least attention," said Richard Elliott, executive director of the Canadian HIV/Aids Legal Network.

It has been seven years since heads of state and government representatives from 189 nations adopted the declaration of Commitment on HIV/Aids.

Their Millennium Development Goals promised to reverse the Aids/HIV epidemic by 2015.

The world is on target to meet those goals. But Aids still provokes passionate responses from those trying to not only reduce the numbers, but improve the lives of those infected.

The singer, Annie Lennox, is one voice among them. She is representing Oxfam at the Mexico City conference.

"The conference cannot be another talking shop that regurgitates what is needed in order to win the battle against the HIV epidemic," she says.

"A plan of action and a clear political will to win the war against HIV and Aids must come out of it."

A few years ago Ms Lennox released an Aids awareness song called 'Sing'.

It contains the lyrics, "You don't need to disrespect yourself again. Don't hide your light behind your fear".

She, and millions of other people around the world, will be hoping those sentiments could become the soundtrack message to this year's conference.