RNA Editing as a General Trait of Ebolaviruses.

RNA editing has been discovered as an essential mechanism for the transcription of the glycoprotein (GP) gene of Ebola virus but not Marburg virus. We developed a rapid transcript quantification assay (RTQA) to analyze RNA transcripts generated through RNA editing and used immunoblotting with a pan-ebolavirus monoclonal antibody to confirm different GP gene-derived products. RTQA successfully quantified GP gene transcripts during infection with representative members of 5 ebolavirus species. Immunoblotting verified expression of the soluble GP and the transmembrane GP. Our results defined RNA editing as a general trait of ebolaviruses. The degree of editing, however, varies among ebolaviruses with Reston virus showing the lowest and Bundibugyo virus the highest degree of editing.

Molecular evidence of hybridization between pig and human Ascaris indicates an interbred species complex infecting humans.

Human ascariasis is a major neglected tropical disease caused by the nematode Ascaris lumbricoides. We report a 296 megabase (Mb) reference-quality genome comprised of 17,902 protein-coding genes derived from a single, representative Ascaris worm. An additional 68 worms were collected from 60 human hosts in Kenyan villages where pig husbandry is rare. Notably, the majority of these worms (63/68) possessed mitochondrial genomes that clustered closer to the pig parasite Ascaris suum than to A. lumbricoides. Comparative phylogenomic analyses identified over 11 million nuclear-encoded SNPs but just two distinct genetic types that had recombined across the genomes analyzed. The nuclear genomes had extensive heterozygosity, and all samples existed as genetic mosaics with either A. suum-like or A. lumbricoides-like inheritance patterns supporting a highly interbred Ascaris species genetic complex. As no barriers appear to exist for anthroponotic transmission of these 'hybrid' worms, a one-health approach to control the spread of human ascariasis will be necessary.

Immune Correlates of Disease Progression in Linked HIV-1 Infection.

Genetic and immunologic analyses of epidemiologically-linked HIV transmission enable insights into the impact of immune responses on clinical outcomes. Human vaccine trials and animal studies of HIV-1 infection have suggested immune correlates of protection; however, their role in natural infection in terms of protection from disease progression is mostly unknown. Four HIV-1+ Cameroonian individuals, three of them epidemiologically-linked in a polygamous heterosexual relationship and one incidence-matched case, were studied over 15 years for heterologous and cross-neutralizing antibody responses, antibody binding, IgA/IgG levels, antibody-dependent cellular cytotoxicity (ADCC) against cells expressing wild-type or CD4-bound Env, viral evolution, Env epitopes, and host factors including HLA-I alleles. Despite viral infection with related strains, the members of the transmission cluster experienced contrasting clinical outcomes including cases of rapid progression and long-term non-progression in the absence of strongly protective HLA-I or CCR5Δ32 alleles. Slower progression and higher CD4/CD8 ratios were associated with enhanced IgG antibody binding to native Env and stronger V1V2 antibody binding responses in the presence of viruses with residue K169 in V2. ADCC against cells expressing Env in the CD4-bound conformation in combination with low Env-specific IgA/IgG ratios correlated with better clinical outcome. This data set highlights for the first time that V1V2-directed antibody responses and ADCC against cells expressing open, CD4-exposed Env, in the presence of low plasma IgA/IgG ratios, can correlate with clinical outcome in natural infection. These parameters are comparable to the major correlates of protection, identified post-hoc in the RV144 vaccine trial; thus, they may also modulate the rate of clinical progression once infected. The findings illustrate the potential of immune correlate analysis in natural infection to guide vaccine development.

Limited anti-HIV neutralizing antibody breadth and potency before and after HIV superinfection in Danish men who have sex with men.

BACKGROUND: The role of the anti-HIV neutralizing antibody response in protecting against HIV superinfection, and changes in neutralizing antibody potency and breadth after HIV superinfection have not been fully elucidated. This study examined the rate of HIV superinfection in men who have sex with men (MSM) also diagnosed with syphilis in Denmark, and the anti-HIV neutralizing antibody response in men who became superinfected. MATERIALS AND METHODS: MSM enrolled in the Danish HIV cohort who acquired syphilis were examined longitudinally for HIV superinfection using a validated next-generation sequencing assay. HIV superinfection cases were matched 3:1 to controls, and neutralizing antibody responses before (cases/controls) and after (cases) HIV superinfection were determined using a 20-pseudovirus panel. RESULTS: Four cases of HIV superinfection were identified from 95 MSM screened for a rate of HIV superinfection of 1.56/100 pys (95% CI = 0.43-4.01). Prior to HIV superinfection neutralizing antibody responses were low in breadth and potency, and did not differ between cases and controls (p = 1.0). In cases, neutralizing antibody responses increased modestly after HIV superinfection. CONCLUSIONS: These data support the theory that the natural neutralizing antibody response to HIV infection may not be the controlling factor in protecting against a subsequent HIV challenge.

Phylogenetic Methods Inconsistently Predict the Direction of HIV Transmission Among Heterosexual Pairs in the HPTN 052 Cohort.

BACKGROUND: We evaluated use of phylogenetic methods to predict the direction of human immunodeficiency virus (HIV) transmission. METHODS: For 33 pairs of HIV-infected patients (hereafter, "index patients") and their partners who acquired genetically linked HIV infection during the study, samples were collected from partners and index patients close to the time when the partner seroconverted (hereafter, "SC samples"); for 31 pairs, samples collected from the index patient at an earlier time point (hereafter, "early index samples") were also available. Phylogenies were inferred using env next-generation sequences (1 tree per pair/subtype). The direction of transmission (DoT) predicted from each tree was classified as correct or incorrect on the basis of which sequences (those from the index patient or the partner) were closest to the root. DoT was also assessed using maximum parsimony to infer ancestral node states for 100 bootstrap trees. RESULTS: DoT was predicted correctly for both single-pair and subtype-specific trees in 22 pairs (67%) by using SC samples and in 23 pairs (74%) by using early index samples. DoT was predicted incorrectly for 4 pairs (15%) by using SC or early index samples. In the bootstrap analysis, DoT was predicted correctly for 18 pairs (55%) by using SC samples and for 24 pairs (73%) by using early index samples. DoT was predicted incorrectly for 7 pairs (21%) by using SC samples and for 4 pairs (13%) by using early index samples. CONCLUSIONS: Phylogenetic methods based solely on the tree topology of HIV env sequences, particularly without consideration of phylogenetic uncertainty, may be insufficient for determining DoT.

Artemisinin resistance phenotypes and K13 inheritance in a Plasmodium falciparum cross and Aotus model.

Concerns about malaria parasite resistance to treatment with artemisinin drugs (ARTs) have grown with findings of prolonged parasite clearance t1/2s (>5 h) and their association with mutations in Plasmodium falciparum Kelch-propeller protein K13. Here, we describe a P. falciparum laboratory cross of K13 C580Y mutant with C580 wild-type parasites to investigate ART response phenotypes in vitro and in vivo. After genotyping >400 isolated progeny, we evaluated 20 recombinants in vitro: IC50 measurements of dihydroartemisinin were at similar low nanomolar levels for C580Y- and C580-type progeny (mean ratio, 1.00; 95% CI, 0.62-1.61), whereas, in a ring-stage survival assay, the C580Y-type progeny had 19.6-fold (95% CI, 9.76-39.2) higher average counts. In splenectomized Aotus monkeys treated with three daily doses of i.v. artesunate, t1/2 calculations by three different methods yielded mean differences of 0.01 h (95% CI, -3.66 to 3.67), 0.80 h (95% CI, -0.92 to 2.53), and 2.07 h (95% CI, 0.77-3.36) between C580Y and C580 infections. Incidences of recrudescence were 57% in C580Y (4 of 7) versus 70% in C580 (7 of 10) infections (-13% difference; 95% CI, -58% to 35%). Allelic substitution of C580 in a C580Y-containing progeny clone (76H10) yielded a transformant (76H10C580Rev) that, in an infected monkey, recrudesced regularly 13 times over 500 d. Frequent recrudescences of ART-treated P. falciparum infections occur with or without K13 mutations and emphasize the need for improved partner drugs to effectively eliminate the parasites that persist through the ART component of combination therapy.

Evolution of HIV-1 within untreated individuals and at the population scale in Uganda.

HIV-1 undergoes multiple rounds of error-prone replication between transmission events, resulting in diverse viral populations within and among individuals. In addition, the virus experiences different selective pressures at multiple levels: during the course of infection, at transmission, and among individuals. Disentangling how these evolutionary forces shape the evolution of the virus at the population scale is important for understanding pathogenesis, how drug- and immune-escape variants are likely to spread in populations, and the development of preventive vaccines. To address this, we deep-sequenced two regions of the HIV-1 genome (p24 and gp41) from 34 longitudinally-sampled untreated individuals from Rakai District in Uganda, infected with subtypes A, D, and inter-subtype recombinants. This dataset substantially increases the availability of HIV-1 sequence data that spans multiple years of untreated infection, in particular for different geographical regions and viral subtypes. In line with previous studies, we estimated an approximately five-fold faster rate of evolution at the within-host compared to the population scale for both synonymous and nonsynonymous substitutions, and for all subtypes. We determined the extent to which this mismatch in evolutionary rates can be explained by the evolution of the virus towards population-level consensus, or the transmission of viruses similar to those that establish infection within individuals. Our findings indicate that both processes are likely to be important.

Quantitation of the latent HIV-1 reservoir from the sequence diversity in viral outgrowth assays.

BACKGROUND: The ability of HIV-1 to integrate into the genomes of quiescent host immune cells, establishing a long-lived latent viral reservoir (LVR), is the primary obstacle to curing these infections. Quantitative viral outgrowth assays (QVOAs) are the gold standard for estimating the size of the replication-competent HIV-1 LVR, measured by the number of infectious units per million (IUPM) cells. QVOAs are time-consuming because they rely on culturing replicate wells to amplify the production of virus antigen or nucleic acid to reproducibly detectable levels. Sequence analysis can reduce the required number of culture wells because the virus genetic diversity within the LVR provides an internal replication and dilution series. Here we develop a Bayesian method to jointly estimate the IUPM and variant frequencies (a measure of clonality) from the sequence diversity of QVOAs. RESULTS: Using simulation experiments, we find our Bayesian approach confers significantly greater accuracy over current methods to estimate the IUPM, particularly for reduced numbers of QVOA replicates and/or increasing actual IUPM. Furthermore, we determine that the improvement in accuracy is greater with increasing genetic diversity in the sample population. We contrast results of these different methods applied to new HIV-1 sequence data derived from QVOAs from two individuals with suppressed viral loads from the Rakai Health Sciences Program in Uganda. CONCLUSIONS: Utilizing sequence variation has the additional benefit of providing information on the contribution of clonality of the LVR, where high clonality (the predominance of a single genetic variant) suggests a role for cell division in the long-term persistence of the reservoir. In addition, our Bayesian approach can be adapted to other limiting dilution assays where positive outcomes can be partitioned by their genetic heterogeneity, such as immune cell populations and other viruses.

Comparative Transcriptomic Response of Primary and Immortalized Macrophages to Murine Norovirus Infection.

Murine norovirus (NoV) is genetically similar to human NoV and offers both an efficient in vitro cell culture system and an animal model by which to investigate the molecular basis of replication. In this study, we present a detailed global view of host alterations to cellular pathways that occur during the progression of a NoV infection. This was accomplished for both Mus musculus BALB/c-derived RAW264.7 (RAW) cells, an immortalized cell line widely used in in vitro replication studies, and primary bone marrow-derived macrophages (BMDM), representing a permissive in vivo target cell in the host. Murine NoV replicated in both cell types, although detected genome copies were approximately one log lower in BMDM compared with RAW cells. RAW and BMDM cells shared an IRF3/7-based IFN response that occurred early in infection. In RAW cells, transcriptional upregulation and INF-ß expression were not coupled in that a significant delay in the detection of secreted INF-ß was observed. In contrast, primary BMDM showed an early upregulation of transcripts and immediate release of INF-ß that might account for lower virus yield. Differences in the transcriptional pathway responses included a marked decrease in expression of key genes in the cell cycle and lipid pathways in RAW cells compared with that of BMDM. Our comparative analysis indicates the existence of varying host responses to virus infection in populations of permissive cells. Awareness of these differences at the gene level will be important in the application of a given permissive culture system to the study of NoV immunity, pathogenesis, and drug development.

Type I interferon signaling attenuates regulatory T cell function in viral infection and in the tumor microenvironment.

Regulatory T cells (Tregs) play a cardinal role in the immune system by suppressing detrimental autoimmune responses, but their role in acute, chronic infectious diseases and tumor microenvironment remains unclear. We recently demonstrated that IFN-α/ß receptor (IFNAR) signaling promotes Treg function in autoimmunity. Here we dissected the functional role of IFNAR-signaling in Tregs using Treg-specific IFNAR deficient (IFNARfl/flxFoxp3YFP-Cre) mice in acute LCMV Armstrong, chronic Clone-13 viral infection, and in tumor models. In both viral infection and tumor models, IFNARfl/flxFoxp3YFP-Cre mice Tregs expressed enhanced Treg associated activation antigens. LCMV-specific CD8+ T cells and tumor infiltrating lymphocytes from IFNARfl/flxFoxp3YFP-Cre mice produced less antiviral and antitumor IFN-γ and TNF-α. In chronic viral model, the numbers of antiviral effector and memory CD8+ T cells were decreased in IFNARfl/flxFoxp3YFP-Cre mice and the effector CD4+ and CD8+ T cells exhibited a phenotype compatible with enhanced exhaustion. IFNARfl/flxFoxp3YFP-Cre mice cleared Armstrong infection normally, but had higher viral titers in sera, kidneys and lungs during chronic infection, and higher tumor burden than the WT controls. The enhanced activated phenotype was evident through transcriptome analysis of IFNARfl/flxFoxp3YFP-Cre mice Tregs during infection demonstrated differential expression of a unique gene signature characterized by elevated levels of genes involved in suppression and decreased levels of genes mediating apoptosis. Thus, IFN signaling in Tregs is beneficial to host resulting in a more effective antiviral response and augmented antitumor immunity.

Characterization of the Neutralizing Antibody Response in a Case of Genetically Linked HIV Superinfection.

This report describes the identification of a genetically confirmed linked heterosexual human immunodeficiency virus (HIV) superinfection (HIV-SI) in a woman with chronic HIV infection who acquired a second strain of the virus from her husband. Serum neutralizing antibody (NAb) responses against their homologous and heterologous viruses, including the superinfecting strain, in the woman and her husband were examined before and after onset of HIV-SI. The woman displayed a moderately potent and broad anti-HIV NAb response prior to superinfection but did not possess NAb activity against the superinfecting strain. This case highlights the unique potential of linked HIV-SI studies to examine natural protection from HIV infection.

Peromyscus leucopus mouse brain transcriptome response to Powassan virus infection.

Powassan virus (POWV) is a tick-borne Flavivirus responsible for life-threatening encephalitis in North America and some regions of Russia. The ticks that have been reported to transmit the virus belong to the Ixodes species, and they feed on small-to-medium-sized mammals, such as Peromyscus leucopus mice, skunks, and woodchucks. We previously developed a P. leucopus mouse model of POWV infection, and the model is characterized by a lack of clinical signs of disease following intraperitoneal or intracranial inoculation. However, intracranial inoculation results in mild subclinical encephalitis from 5 days post infection (dpi), but the encephalitis resolves by 28 dpi. We used RNA sequencing to profile the P. leucopus mouse brain transcriptome at different time points after intracranial challenge with POWV. At 24 h post infection, 42 genes were significantly differentially expressed and the number peaked to 232 at 7 dpi before declining to 31 at 28 dpi. Using Ingenuity Pathway Analysis, we determined that the genes that were significantly expressed from 1 to 15 dpi were mainly associated with interferon signaling. As a result, many interferon-stimulated genes (ISGs) were upregulated. Some of the ISGs include an array of TRIMs (genes encoding tripartite motif proteins). These results will be useful for the identification of POWV restriction factors.

Profiling invasive Plasmodium falciparum merozoites using an integrated omics approach.

The symptoms of malaria are brought about by blood-stage parasites, which are established when merozoites invade human erythrocytes. Our understanding of the molecular events that underpin erythrocyte invasion remains hampered by the short-period of time that merozoites are invasive. To address this challenge, a Plasmodium falciparum gamma-irradiated long-lived merozoite (LLM) line was developed and investigated. Purified LLMs invaded erythrocytes by an increase of 10-300 fold compared to wild-type (WT) merozoites. Using an integrated omics approach, we investigated the basis for the phenotypic difference. Only a few single nucleotide polymorphisms within the P. falciparum genome were identified and only marginal differences were observed in the merozoite transcriptomes. By contrast, using label-free quantitative mass-spectrometry, a significant change in protein abundance was noted, of which 200 were proteins of unknown function. We determined the relative molar abundance of over 1100 proteins in LLMs and further characterized the major merozoite surface protein complex. A unique processed MSP1 intermediate was identified in LLM but not observed in WT suggesting that delayed processing may be important for the observed phenotype. This integrated approach has demonstrated the significant role of the merozoite proteome during erythrocyte invasion, while identifying numerous unknown proteins likely to be involved in invasion.

Multimethod Longitudinal HIV Drug Resistance Analysis in Antiretroviral-Therapy-Naive Patients.

The global intensification of antiretroviral therapy (ART) can lead to increased rates of HIV drug resistance (HIVDR) mutations in treated and also in ART-naive patients. ART-naive HIV-1-infected patients from Cameroon were subjected to a multimethod HIVDR analysis using amplification-refractory mutation system (ARMS)-PCR, Sanger sequencing, and longitudinal next-generation sequencing (NGS) to determine their profiles for the mutations K103N, Y181C, K65R, M184V, and T215F/Y. We processed 66 ART-naive HIV-1-positive patients with highly diverse subtypes that underlined the predominance of CRF02_AG and the increasing rate of F2 and other recombinant forms in Cameroon. We compared three resistance testing methods for 5 major mutation sites. Using Sanger sequencing, the overall prevalence of HIVDR mutations was 7.6% (5/66) and included all studied mutations except K65R. Comparing ARMS-PCR with Sanger sequencing as a reference, we obtained a sensitivity of 100% (5/5) and a specificity of 95% (58/61), caused by three false-positive calls with ARMS-PCR. For 32/66 samples, we obtained NGS data and we observed two additional mismatches made up of minority variants (7% and 18%) that might not be clinically relevant. Longitudinal NGS analyses revealed changes in HIVDR mutations in all five positive subjects that could not be attributed to treatment. In one of these cases, superinfection led to the temporary masking of a resistant virus. HIVDR mutations can be sensitively detected by ARMS-PCR and sequencing methods with comparable performances. Longitudinal changes in HIVDR mutations have to be considered even in the absence of treatment.

Reduced Frequency of Cells Latently Infected With Replication-Competent Human Immunodeficiency Virus-1 in Virally Suppressed Individuals Living in Rakai, Uganda.

Background: Human immunodeficiency virus type 1 (HIV-1) persists in latently infected resting CD4+ T cells (rCD4 cells), posing a major barrier to curing HIV-1 infection. Previous studies have quantified this pool of latently infected cells in Americans; however, no study has quantified this reservoir in sub-Saharan Africans, who make up the largest population of HIV-1-infected individuals globally. Methods: Peripheral blood was collected from 70 virally suppressed HIV-1-infected individuals from Rakai District, Uganda, who had initiated antiretroviral therapy (ART) during chronic infection. The quantitative viral outgrowth assay was used to determine frequency of latently infected rCD4 cells containing replication-competent virus. Multivariate regression was used to identify correlates of reservoir size and to compare reservoir size between this Ugandan cohort and a previously studied cohort of individuals from Baltimore, Maryland. Results: The median frequency of latently infected rCD4 cells in this Ugandan cohort was 0.36 infectious units per million cells (IUPM; 95% confidence interval, 0.26-0.55 IUPM), 3-fold lower than the frequency observed in the Baltimore cohort (1.08 IUPM; .72-1.49 IUPM; P < .001). Reservoir size in Ugandans was correlated positively with set-point viral load and negatively with duration of viral suppression. Conclusions: Virally suppressed Ugandans had a 3-fold lower frequency of rCD4 cells latently infected with replication-competent HIV-1, compared with previous observations in a cohort of American patients, also treated with ART during chronic infection. The biological mechanism driving the observed smaller reservoir in Ugandans is of interest and may be of significance to HIV-1 eradication efforts.

Treatment of Chronic Asymptomatic Plasmodium falciparum Infection Does Not Increase the Risk of Clinical Malaria Upon Reinfection.

Background: Chronic asymptomatic Plasmodium falciparum infections are common in endemic areas and are thought to contribute to the maintenance of malaria immunity. Whether treatment of these infections increases the subsequent risk of clinical episodes of malaria is unclear. Methods: In a 3-year study in Mali, asymptomatic individuals with or without P. falciparum infection at the end of the 6-month dry season were identified by polymerase chain reaction (PCR), and clinical malaria risk was compared during the ensuing 6-month malaria transmission season. At the end of the second dry season, 3 groups of asymptomatic children were identified: (1) children infected with P. falciparum as detected by rapid diagnostic testing (RDT) who were treated with antimalarials (n = 104), (2) RDT-negative children whose untreated P. falciparum infections were detected retrospectively by PCR (n = 55), and (3) uninfected children (RDT/PCR negative) (n = 434). Clinical malaria risk during 2 subsequent malaria seasons was compared. Plasmodium falciparum-specific antibody kinetics during the dry season were compared in children who did or did not harbor asymptomatic P. falciparum infections. Results: Chronic asymptomatic P. falciparum infection predicted decreased clinical malaria risk during the subsequent malaria season(s); treatment of these infections did not alter this reduced risk. Plasmodium falciparum-specific antibodies declined similarly in children who did or did not harbor chronic asymptomatic P. falciparum infection during the dry season. Conclusions: These findings challenge the notion that chronic asymptomatic P. falciparum infection maintains malaria immunity and suggest that mass drug administration during the dry season should not increase the subsequent risk of clinical malaria.

Contrasting antibody responses to intrasubtype superinfection with CRF02_AG.

HIV superinfection describes the sequential infection of an individual with two or more unrelated HIV strains. Intersubtype superinfection has been shown to cause a broader and more potent heterologous neutralizing antibody response when compared to singly infected controls, yet the effects of intrasubtype superinfection remain controversial. Longitudinal samples were analyzed phylogenetically for pol and env regions using Next-Generation Sequencing and envelope cloning. The impact of CRF02_AG intrasubtype superinfection was assessed for heterologous neutralization and antibody binding responses. We compared two cases of CRF02_AG intrasubtype superinfection that revealed complete replacement of the initial virus by superinfecting CRF02_AG variants with signs of recombination. NYU6564, who became superinfected at an early time point, exhibited greater changes in antibody binding profiles and generated a more potent neutralizing antibody response post-superinfection compared to NYU6501. In contrast, superinfection occurred at a later time point in NYU6501 with strains harboring significantly longer V1V2 regions with no observable changes in neutralization patterns. Here we show that CRF02_AG intrasubtype superinfection can induce a cross-subtype neutralizing antibody response, and our data suggest timing and/or superinfecting viral envelope characteristics as contributing factors. These results highlight differential outcomes in intrasubtype superinfection and provide the first insight into cases with CRF02_AG, the fourth most prevalent HIV-1 strain worldwide.

In vivo characterization of an Hfq protein encoded by the Bacillus anthracis virulence plasmid pXO1.

BACKGROUND: Bacterial Hfq proteins post-transcriptionally regulate gene expression, primarily by mediating the interaction between sRNAs (small RNAs) and their target mRNAs. The role of Hfq-based regulation has been well defined in Gram-negative bacteria, but comparatively less is known about the impact of Hfq proteins in Gram-positive species. The Gram-positive pathogen Bacillus anthracis (causative agent of anthrax) is distinct in that it expresses three homologs of Hfq: Hfq1 and Hfq2 from the chromosome, and Hfq3 from the pXO1 virulence plasmid. RESULTS: In this study, we utilized overexpression as a strategy to examine the impact of Hfq3 on B. anthracis physiology. The increase in Hfq3 protein levels led to anomalous cell shape and chain formation, which manifested as a severe growth defect. This phenotype was specific to B. anthracis, as Hfq3 expression in B. subtilis at similar levels was not toxic. Toxicity was dependent on residues on the distal face of Hfq3 that are involved in mRNA binding in other bacterial species. CONCLUSIONS: Thus, we hypothesize that Hfq3 interacts with RNA(s) involved in essential functions in the B. anthracis cell, leading to increased binding upon overexpression that either sequesters or accelerates degradation of RNAs important for growth. These results not only aid in elucidating the role of Hfq proteins in B. anthracis, but also contribute to our current understanding of Hfq in Gram-positive bacteria.

Sequence of Reston Virus Isolate AZ-1435, an Ebolavirus Isolate Obtained during the 1989-1990 Reston Virus Epizootic in the United States.

Reston virus (RESTV) was discovered in 1989-1990 during three connected epizootics of highly lethal viral hemorrhagic fever among captive macaques in primate housing facilities in the United States and Philippines. Currently, only one RESTV isolate from that outbreak (named Pennsylvania) has been sequenced. Here, we report the sequence of a second isolate, Reston virus/M.fascicularis-tc/USA/1990/Philippines89-AZ1435.

Treatment as Prevention: Characterization of Partner Infections in the HIV Prevention Trials Network 052 Trial.

HIV Prevention Trials Network 052 demonstrated that antiretroviral therapy (ART) prevents HIV transmission in serodiscordant couples. HIV from index-partner pairs was analyzed to determine the genetic linkage status of partner infections. Forty-six infections were classified as linked, indicating that the index was the likely source of the partner's infection. Lack of viral suppression and higher index viral load were associated with linked infection. Eight linked infections were diagnosed after the index started ART: 4 near the time of ART initiation and 4 after ART failure. Linked infections were not observed when the index participant was stably suppressed on ART.