Sub-Saharan Africa is still bearing the brunt of the HIV/Aids epidemic, a UNAids report has revealed.
Sub-Saharan Africa still sees the most cases of HIV/Aids
Almost three-quarters of deaths from Aids in 2006 occurred there and two-thirds of those living with HIV are in that area.
UNAids says there are an estimated 39.5 million people now living with HIV.
The number living with the virus has increased everywhere, with the most striking increases in East Asia and Central Asia/Eastern Europe.
Some countries, such as Uganda, are seeing a resurgence in new HIV infection rates which were previously stable or declining.
The report, which is based on disease surveillance around the world, says there were an estimated 4.3 million new HIV infections this year, with 2.8 million of these occurring in sub-Saharan Africa.
Forty per cent of new infections were in people aged 15 to 24-years-old.
In 2006, 2.9 million died of Aids-related illnesses.
The report says: "The future course of the world's HIV epidemics hinges in many respects on the behaviours young people adopt and maintain, and the factors that affect those choices."
Women at risk
In Eastern Europe/Central Asia there was a 70% increase in the number of new infections seen in 2006 compared with 2004 - 270,000 compared with 160,000.
In South-East Asia, the number of new infections rose by 15% from 2004 to 2006.
The increase is fuelled by high-risk behaviour such as injecting drug use, unprotected paid-for sex and unprotected sex between men.
Across the world, women are more likely to be affected by HIV than ever before, the report reveals.
In sub-Saharan Africa, there are around 14 women living with HIV for every 10 men.
UNAids also says the HIV epidemics in Mozambique, South Africa and Swaziland are continuing to grow.
Zimbabwe is the only southern African country where the prevalence of HIV among adults is falling.
Dr Peter Piot, UNAids executive director, warned it was vital to sustain HIV prevention efforts, and to ensure they were adapted where necessary to target the most vulnerable.
He said "We need to greatly intensify life-saving prevention efforts while we expand HIV treatment programmes."
In some countries, even limited resources have shown benefit when correctly targeted.
For example, China has had success in reducing HIV rates among sex workers, and injecting drug users, and in Portugal HIV diagnoses among drug injectors fell by almost a third between 2001 and 2005 following the implementation of special prevention programmes.
However, the report warns that in many countries prevention programmes are not reaching the people most at risk.
Dr Anders Nordström, acting director-general of the World Health Organization, said: "It is imperative that we continue to increase investment in both HIV prevention and treatment services to reduce unnecessary deaths and illness from this disease."
Deborah Jack, chief executive of the UK National Aids Trust said: "Sadly many countries, including the UK, are not sustaining HIV prevention programmes and are seeing rises in new infections. If resource poor countries are able to reduce their HIV rates there are clearly lessons to be learnt."
Hilary Benn, the International Development Secretary, said: "While most countries now recognise the existence of Aids, too many countries ignore the reality.
"The report shows clearly that HIV prevention must be targeted at the people most at risk of infection - young people, women and young girls, men who have sex with men, commercial sex workers and injecting drug users.
"This is not a time for embarrassment, this is about telling it straight because it is about saving people¿s lives."