A new human immunodeficiency virus type 1 circulating recombinant form from Tanzania

It is becoming increasingly important to identify and to study human immuno deficiency virus type 1 (HIV-1) circulating recombinant forms (CRFs) with e vidence of epidemic spread, since mosaic strains arise frequently, especial ly in populations where multiple subtypes cocirculate. We describe the almo st complete nucleotide sequence of 3 subtype C and D recombinant viruses, s elected from a pool of 13 D(gag)-D/C/D(env) perinatally infected infants fr om Dar es Salaam, Tanzania, All three genomes had cross-over points with ap proximately the same genomic localization. The subtype C-Like sequences wer e located within pol, vif, vpr, vpu, the first exons of rev and tat, V3, an d the U3-R regions of the LTR, Phylogenetic analyses of the full-length gen omic sequences from these viruses showed the formation of a distinct subclu ster on the HIV-1 subtype D branch, The pattern of recombination of genomes belonging to this new CRF, named CRF10_CD, might have resulted from indepe ndent recombination events occurring at high frequency or from a single sou rce that originated earlier in this population. Future surveys will be need ed to determine the potential of this CRF for epidemic spread.