Last year, there was an estimated 2.7 million becoming newly infected with HIV, while 1.8 million people died from Aids.
UNAIDS – the Joint United Nations Programme on HIV/Aids – reports that the epidemic has slowed down, with a 21% reduction in the annual number of new cases since 1997.
But while some parts of the world including sub-Saharan Africa have seen a stabilising or decrease in new infections, others, such as eastern Europe and Central Asia, have seen an increase – largely due to spread among people who inject drugs.
It is 30 years since Aids was first reported. World Aids Day is today.
In Scotland, 6845 cases of HIV infection have been reported, of whom 1817 are known to have died. It is now estimated that 4059 men and women have been diagnosed and are living with HIV in Scotland.
Health Protection Scotland said access to treatment and care was good, and therapy continued to be successful.
However, Jane Morel, Scottish area manager for the Terrence Higgins Trust, said: "The number of people living with HIV in Scotland has reached a worrying high at over 5000."
This figure includes the 4059 diagnosed, and an estimated 1000 undiagnosed.
"We are seeing a drop in HIV and Aids-related deaths but there are still far too many people being diagnosed late, 46% of people, which threatens their lives and makes them more infectious, placing their partners at increased risk of acquiring HIV," Ms Morel added
"We are also seeing more cuts and threats to social services for people living with HIV, with vital support withdrawn in Glasgow in the last few years and services at risk in Grampian and Edinburgh. HIV is still a complex and highly stigmatised illness."
Stuart, a 57-year-old grand-father-of-five, from Leith, is one of those living with HIV, having contracted it from his drug addict wife 22 years ago. She has since died.
He speaks highly of Milestone House in Edinburgh, where specialist nurses and social care workers provide short-term residential support. It is mostly funded by the city council and costs £500,000 a year to run. But it is again under threat, with the council reviewing its funding.
He said: "It's brilliant, it really is. But the heart has been ripped out of it. The council have made sure of that with their funding."
An Edinburgh City Council spokesman said: "This city has an excellent record in caring for those who have HIV. The council remains committed to providing the best possible services."