A new study has suggested that a recently discovered HIV strain leads to significantly faster development of AIDS than currently prevalent forms.

The period from infection to development of AIDS was the shortest reported among HIV-1 types, at around five years.

There are over 60 different epidemic strains of HIV-1 in the world, and geographic regions are often dominated by one or two of these. If a person becomes infected with two different strains, they can fuse and a recombined form can occur.

"Recombinants seem to be more vigorous and more aggressive than the strains from which they developed," Angelica Palm, a doctoral student at Lund University in Sweden, explained.

The recombinant studied is called A3by02 and is a cross between the two most common strains in Guinea-Bissau, West Africa - 02AG and A3. It has previously been described by Joakim Esbjornsson, a postdoctoral fellow at the University of Oxford, who is a co-author of the study.

So far, the new strain has only been identified in West Africa, but other studies have shown that the global spread of different recombinants is increasing.

In countries and regions with high levels of immigration, such as the US and Europe, the trend is towards an increasingly mixed and complex HIV flora, unlike in the beginning of the epidemic when a small number of non-recombinant variants of the virus dominated. There is therefore reason to be wary of HIV recombinants in general.