Genetic characterization of eight full-length HIV type 1 genomes from the Democratic Republic of Congo (DRC) reveal a new subsubtype, A5, in the A radiation that predominates in the recombinant structure of CRF26_A5U.

In this study, we characterized HIV-1 strains from the Democratic Republic of Congo (DRC), previously described as divergent subtype A (n = 1, 97CD.KMST91) or untypable (n = 7) in the V3-V5 env region. Four strains had the same structure over the entire genome, including alternating fragments of a new subsubtype, A5, within the subtype A radiation and fragments that remain unclassified. Therefore, the cluster of new viruses represents a new circulating recombinant, CRF26_A5U. Three additional strains were unique recombinants with the newly described CRF26_A5U and subtype C. Finally, the nearly full-length sequence of 97CD.KMST91 showed that this strain also consisted of alternating fragments of a divergent subtype A lineage and unclassified fragments, although different from previously reported A and U sequences. The high genetic distances among the different CRF26-A5U strains suggest their longstanding presence in the DRC.

Characterization of an old complex circulating recombinant form, CRF27_cpx, originating from the Democratic Republic of Congo (DRC) and circulating in France.

Full-length genomes were characterized for two samples, 02CD-LBR024 from the Democratic Republic of Congo (DRC) and 04FR-CD-KZS from France, that formed a separate subcluster with a previously characterized env subtype E isolate from DRC with a recombinant structure different from CRF01-AE. Since the three viruses are clearly epidemiologically unlinked and share the same complex recombinant structure, they represent a circulating recombinant form, designated as CRF27-cpx. The recombination pattern involves six different HIV-1 subtypes (A, E, G, H, J, and K) and a small unclassified fragment. The genetic distances are relatively high, indicating that CRF27-cpx evolved over a long time. Their prevalence is low (0.75%) and remained stable over time in the DRC. The existence of the 04FR.CD.KZS virus, in a patient who recently seroconverted in France, confirmed that these strains now circulate outside the DRC. Continuous monitoring of HIV-1 strains thus remains important to allow early identification of the introduction of new variants.

Distribution of HIV-1 variants in the Democratic Republic of Congo suggests increase of subtype C in Kinshasa between 1997 and 2002.

The Democratic Republic of Congo (DRC) is characterized by low and stable HIV prevalences and high HIV-1 genetic diversity and is most probably the epicenter of HIV-1 group M. Our major goal was to study the distribution of HIV-1 variants over a 5-year period against a background of political instability and civil war. A total of 288 HIV-1-positive samples collected in 2002 from sentinel population groups in an HIV serosurveillance study performed in 4 cities (Kinshasa [capital city], Mbuji-Mayi [south], Lubumbashi [southeast], and Kisangani [northeast]) were genetically characterized by sequencing and phylogenetic analysis of the V3-V5 env region. The results were compared with those obtained in 1997. Similarly, as in 1997, an extremely high genetic diversity of HIV-1 strains overall and a heterogeneous geographic distribution were seen in 2002. All subtypes and several circulating recombinant forms were present, high intrasubtype diversity was observed, and 5.6% of the samples could not be classified. In each geographic region of the DRC, the genetic diversity was significantly higher than in neighboring countries. Comparison of subtype distribution in similar population groups in Kinshasa in 1997 and 2002 revealed an overall increase of subtype C in Kinshasa from 2.1% to 9.7% and, more precisely, from 0% to 18.9% in female sex workers (P = 0.013). Genetic characterization of HIV-positive samples from sentinel surveys adds significant additional information on new trends in the HIV epidemic. These changes could have implications regarding the spread of HIV infection in the DRC as well on vaccine and/or treatment strategies.