Confirmed infection with HTLV-II (human T cell leukemia virus type II) has been described only in rare cases. The major limitation to serological diagnosis of HTLV-II has been the difficulty of distinguishing HTLV-II from HTLV-I (human T cell leukemia virus type I) infection, because of substantial cross-reactivity between the viruses. A sensitive modification of the polymerase chain reaction method was used to provide unambiguous molecular evidence that a significant proportion of intravenous drug abusers are infected with HTLV, and the majority of these individuals are infected with HTLV-II rather than HTLV-I. Of 23 individuals confirmed by polymerase chain reaction analysis to be infected with HTLV, 21 were identified to be infected with HTLV-II, and 2 were infected with HTLV-I. Molecular identification of an HTLV-II--infected population provides an opportunity to investigate the pathogenicity of HTLV-II in humans.

HIV-1 strain diversity in Cameroon did not significantly change, suggesting a mature and relatively stable epidemic.

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The Celera Diagnostics ViroSeq HIV-1 Genotyping System is a Food and Drug Administration-cleared, integrated system for sequence-based analysis of drug resistance mutations in subtype B human immunodeficiency virus type 1 (HIV-1) protease and reverse transcriptase (RT). We evaluated the performance of this system for the analysis of diverse HIV-1 strains. Plasma samples were obtained from 126 individuals from Uganda, Cameroon, South Africa, Argentina, Brazil, and Thailand with viral loads ranging from 2.92 to >6.0 log 10 copies/ml. HIV-1 genotyping was performed with the ViroSeq system. HIV-1 subtyping was performed by using phylogenetic methods. PCR products suitable for sequencing were obtained for 125 (

BackgroundXenotropic Murine Leukemia Virus-related Virus (XMRV) is a human gammaretrovirus recently identified in prostate cancer tissue and in lymphocytes of patients with chronic fatigue syndrome. To establish the etiologic role of XMRV infection in human disease requires large scale epidemiologic studies. Development of assays to detect XMRV-specific antibodies would greatly facilitate such studies. However, the nature and kinetics of the antibody response to XMRV infection have yet to be determined.ResultsThree rhesus macaques were infected with XMRV to determine the dynamics of the antibody responses elicited by infection with XMRV. All macaques developed antibodies to XMRV during the second week of infection, and the predominant responses were to the envelope protein gp70, transmembrane protein p15E, and capsid protein p30. In general, antibody responses to gp70 and p15E appeared early with higher titers than to p30, especially in the early period of seroconversion. Antibodies to gp70, p15E and p30 persisted to 158 days and were substantially boosted by re-infection, thus, were identified as useful serologic markers. Three high-throughput prototype assays were developed using recombinant proteins to detect antibodies to these viral proteins. Both gp70 and p15E prototype assays demonstrated 100% sensitivity by detecting all Western blot (WB) positive serial bleeds from the XMRV-infected macaques and good specificity (99.5-99.9%) with blood donors. Seroconversion sensitivity and specificity of the p30 prototype assay were 92% and 99.4% respectively.ConclusionsThis study provides the first demonstration of seroconversion patterns elicited by XMRV infection. The nature and kinetics of antibody responses to XMRV in primates were fully characterized. Moreover, key serologic markers useful for detection of XMRV infection were identified. Three prototype immunoassays were developed to detect XMRV-specific antibodies. These assays demonstrated good sensitivity and specificity; thus, they will facilitate large scale epidemiologic studies of XMRV infection in humans.

The prevalence of HIV infection in Brazil is one of the highest in the world. In addition, transfusion-transmitted HIV accounts for 2.3% of all AIDS cases in Brazil. The objective of this study was to evaluate genetic diversity and distribution of HIV-1 strains circulating in the blood-donor population. We characterized 43 seropositive blood units collected from volunteer blood donors residing throughout Rio de Janeiro, Brazil. Viral RNA was extracted from plasma, reverse transcribed, and amplified by nested polymerase chain reaction (PCR) using HIV group M degenerate primers. Genetic heterogeneity was evaluated by direct automated cycle sequencing of the following gene fragments: gag p24 (399 bp), env C2V3 (345 bp), and env gp41 (369 bp). Phylogenetic analysis reflected the complexity of the Brazilian HIV epidemic: the majority of specimens, 33 of 43 (76.7%) were subtype B, and 6 of 43 (14%) were subtype F. The remaining 4 samples (9.3%) involved potential mosaic viruses of subtypes B and F or B and D. This survey is the first to document HIV-1 genetic variation in the Brazilian blood-donor population.

The current env-based subtyping of human T-cell lymphotropic virus type II (HTLV-II) identifies only two heterogenetic groups, HTLV-IIa and HTLV-IIb. To better understand the genetic diversity and phylogeny of HTLV-II, we examined the most divergent genomic region of HTLV-II, the long terminal repeat, by using restriction fragment length polymorphism (RFLP) and sequence analysis. Long terminal repeat sequences were amplified from peripheral blood mononuclear cells by PCR and digested with seven restriction endonucleases that differentiated HTLV-II into five HTLV-IIa (IIa0 to IIa4) and six HTLV-IIb (IIb0 to IIb5) restriction types, with HTLV-IIa0 and HTLV-IIb0 being prototypes for the MoT and NRA isolates, respectively. We examined 169 HTLV-II-infected samples, including 123 from blood donors and intravenous drug users(IDU) from the Americas, 16 from IDU from Europe, and 30 from Amerindians. Of the 169 samples, 109 (64.5%) were categorized as HTLV-IIa and 60 (35.5%) were categorized as HTLV-IIb. The predominant restriction types seen among the U.S. blood donors and U.S. IDU were IIa0 (68.7%) and IIb4 (10.4%). Four Spanish and seven Italian samples were IIb4, while five Norwegian samples were IIa2. Twelve Guaymi and all ten Seminole samples were single restriction types (IIb1 and IIb5, respectively), whereas the two Navajo and six Pueblo samples had a mixture of restriction types IIa0, IIa4, and IIb5. Of the HTLV-IIb restriction types observed in the U.S. non-Indians, 42.8% appear to have originated from the North Amerindian (IIb5), while 57.2% were similar to the European IIb4 restriction type. Sequences of 15 selected HTLV-II samples were determined and phylogenetically compared with 7 previously published HTLV-II LTR sequences. The derived topologies revealed three HTLV-IIa phylogroups (A-I to A-III) and four HTLV-IIb phylogroups (B-I to B-IV). Furthermore, the HTLV-IIa phylogroups appear to have evolved from the HTLV-IIb phylogroups. In the HTLV-IIa cluster, a Navajo (A-I) and a Brazilian (A-II) sequence formed separate phylogroups, while the remaining IIa sequences formed a single phylogroup (A-III). The four HTLV-IIb phylogroups were represented predominantly by a New York IDU (B-I), European IDU (B-II), North Amerindian and NRA (B-III), and Central Guaymi Indian (B-IV) sequence(s). Comparison of the phylogenetic data with the RFLP results revealed that results of the two methods correlated completely, demonstrating the ability of the RFLP method to predict the phylogroup of HTLV-II-infected samples accurately and quickly.