Re-analysis of human immunodeficiency virus type 1 isolates from Cyprus and Greece, initially designated 'subtype I', reveals a unique complex A/G/H/K/? mosaic pattern

Human immunodeficiency virus type 1 (HIV-1) has been classified into three main groups and 11 distinct subtypes. Moreover, several circulating recombi nant forms (CRFs) of HIV-1 have been recently documented to have spread wid ely causing extensive HIV-1 epidemics. A subtype, initially designated I (C RF04_cpx), was documented in Cyprus and Greece and was found to comprise re gions of sequence derived from subtypes A and G as well as regions of uncla ssified sequence. Reanalysis of the three full-length CRF04_cpx sequences t hat were available revealed a mosaic genomic organization of unique complex ity comprising regions of sequence from at least five distinct subtypes, A, G, H, K and unclassified regions. These strains account for approximately 2% of the total HIV-1-infected population in Greece, thus providing evidenc e of the great capability of HIV-1 to recombine and produce highly divergen t strains which can be spread successfully through different infection rout es.