By Grant Ferrett
BBC Africa reporter
In its annual report on HIV and Aids, the United Nations agency, UNAids, once again highlights sub-Saharan Africa as by far the worst affected region.
Some 27 million are HIV positive in Africa
Of the estimated 40m people worldwide living with HIV, about two-thirds are in sub-Saharan Africa, with young women particularly at risk.
Although the UN says it detects increasing political support for tackling the spread of the virus, the report gives little cause for optimism.
HIV infection rates vary widely across Africa, from under one per cent in Mauritania in the north-west, to nearly 39% in Swaziland and Botswana in the south.
As in previous years, southern Africa is at the heart of the global Aids crisis.
The UN report says the epidemic has reached devastating proportions in the region.
In South Africa, which already has more people living with HIV and Aids than any other country, the report predicts that the worst still lies ahead, with the numbers of deaths continuing to increase rapidly over the next few years.
Young women in Africa are bearing the brunt of the onslaught.
According to various national surveys they are two-and-a-half times more likely to be infected as their male counterparts.
The UN says this is explained by a number of factors - for example, young women tend to start having sex earlier and are more susceptible to contracting the virus than young men.
In the gloom, there are glimmers of hope.
Infection rates have dropped sharply in countries such as Rwanda and Ethiopia, and remained low in others such as Senegal.
The report also welcomes what it describes as an upsurge in political support against Aids in the region and increased funding.
But it acknowledges an almost complete absence of large-scale HIV prevention programmes and of drugs treatment.
For sub-Saharan Africa, the horror of Aids shows few signs of abating.