Research Articles (Medical Virology)

Permanent URI for this collection

https://scholar.sun.ac.za/handle/10019.1/3153

Browse

Now showing 1 - 20 of 106

38 years after its discovery, Ebola virus spins out of control
(South African Centre for Epidemiological Modelling and Analysis (SACEMA), 2014-09) Preiser, Wolfgang
The evolutionary origin of Ebolaviruses is not very clear. The simple notion that these viruses have been circulating for many millennia in wildlife in tropical parts of Africa, occasionally spilling over into human populations, often brought on by human activities, may not be correct or at least incomplete. Over time a number of Ebola disease outbreaks reported and a pattern in the outbreak response seemed to have been established. A lot was also learnt about Ebola viruses, their epidemiology and ecology. However, the 2014 Ebola outbreak challenges our understanding in many respects.
Aberrant in vitro HLA-DR expression in patients with chronic fatigue
(Health and Medical Publishing Group (HMPG), 1990-08) Van Greune, C. H. J.; Bouic, P. J. D.
To the Editor: The chronic fatigue syndrome (CFS) is a clinical entity characterised by chronic fluctuating fatigue associated-with a multitude of related symptoms, which may vary between patients. It is of unknown causation, but usually follows a presumed acute viral infection.
Academic publishing in pandemic times
(ASSAf, 2020-09-21) Preiser, Wolfgang; Preiser, Rika
ENGLISH ABSTRACT: Even though it tends to feel like ages, it has not been that long since the final days of 2019, when cases of severe respiratory illness (now known as COVID-19), caused by a previously unknown coronavirus (since named SARSCoV- 2), were reported from China. The ongoing COVID-19 pandemic has brought unprecedented disruption to almost every area of our daily and professional lives. Science has not been spared, nor has scientific publishing. Most researchers have been unable to continue with their work, and many had to all but re-invent their teaching. Quite a few have re-invented themselves as coronavirus researchers.1 As biomedical researchers, we are astonished to see how much interest the public is taking in our findings. For no other disease do members of the public so fervently seek out reports in traditional and social media about the latest research findings. These reports often trigger controversial discussions, mostly on social media platforms, about rather complicated aspects of epidemiology, diagnostics, pathogenesis or therapy. Many of these issues are matters outside the realm of everyday life and normally left to experts to assess the evidence and translate it into practice.
Analyses of HIV-1 integrase sequences prior to South African national HIV-treatment program and availability of integrase inhibitors in Cape Town, South Africa
(Nature Publishing Group, 2018) Brado, Dominik; Obasa, Adetayo Emmanuel; Ikomey, George Mondinde; Cloete, Ruben; Singh, Kamalendra; Engelbrecht, Susan; Neogi, Ujjwal; Jacobs, Graeme Brendon
ENGLISH ABSTRACT: HIV-Integrase (IN) has proven to be a viable target for highly specific HIV-1 therapy. We aimed to characterize the HIV-1 IN gene in a South African context and identify resistance-associated mutations (RAMs) against available first and second generation Integrase strand-transfer inhibitors (InSTIs). We performed genetic analyses on 91 treatment-naïve HIV-1 infected patients, as well as 314 treatment-naive South African HIV-1 IN-sequences, downloaded from Los Alamos HIV Sequence Database. Genotypic analyses revealed the absence of major RAMs in the cohort collected before the broad availability of combination antiretroviral therapy (cART) and INSTI in South Africa, however, occurred at a rate of 2.85% (9/314) in database derived sequences. RAMs were present at IN-positions 66, 92, 143, 147 and 148, all of which may confer resistance to Raltegravir (RAL) and Elvitegravir (EVG), but are unlikely to affect second-generation Dolutegravir (DTG), except mutations in the Q148 pathway. Furthermore, protein modeling showed, naturally occurring polymorphisms impact the stability of the intasome-complex and therefore may contribute to an overall potency against InSTIs. Our data suggest the prevalence of InSTI RAMs, against InSTIs, is low in South Africa, but natural polymorphisms and subtype-specific differences may influence the effect of individual treatment regimens.
Analysis of viral diversity in relation to the recency of HIV-1C infection in Botswana
(Public Library of Science, 2016) Moyo, Sikhulile; Vandormael, Alain; Wilkinson, Eduan; Engelbrecht, Susan; Gaseitsiwe, Simani; Kotokwe, Kenanao P.; Musonda, Rosemary; Tanser, Frank; Essex, Max; Novitsk, Vladimir; De Oliveira, Tulio
Background: Cross-sectional, biomarker methods to determine HIV infection recency present a promising and cost-effective alternative to the repeated testing of uninfected individuals. We evaluate a viral-based assay that uses a measure of pairwise distances (PwD) to identify HIV infection recency, and compare its performance with two serologic incidence assays, BED and LAg. In addition, we assess whether combination BED plus PwD or LAg plus PwD screening can improve predictive accuracy by reducing the likelihood of a false-recent result. Methods: The data comes from 854 time-points and 42 participants enrolled in a primary HIV-1C infection study in Botswana. Time points after treatment initiation or with evidence of multiplicity of infection were excluded from the final analysis. PwD was calculated from quasispecies generated using single genome amplification and sequencing. We evaluated the ability of PwD to correctly classify HIV infection recency within <130, <180 and <360 days post-seroconversion using Receiver Operator Characteristics (ROC) methods. Following a secondary PwD screening, we quantified the reduction in the relative false-recency rate (rFRR) of the BED and LAg assays while maintaining a sensitivity of either 75, 80, 85 or 90%. Results: The final analytic sample consisted of 758 time-points from 40 participants. The PwD assay was more accurate in classifying infection recency for the 130 and 180-day cut-offs when compared with the recommended LAg and BED thresholds. A higher AUC statistic confirmed the superior predictive performance of the PwD assay for the three cut-offs. When used for combination screening, the PwD assay reduced the rFRR of the LAg assay by 52% and the BED assay by 57.8% while maintaining a 90% sensitivity for the 130 and 180-day cut-offs respectively. Conclusion: PwD can accurately determine HIV infection recency. A secondary PwD screening reduces misclassification and increases the accuracy of serologic-based assays.
Anti-HIV-1 activity of salivary MUC5B and MUC7 mucins from HIV patients with different CD4 counts
(BioMed Central, 2010-10) Habte, Habtom H.; De Beer, Corena; Lotz, Zoe E.; Roux, Paul; Mall, Anwar S.
Background: We have previously shown that MUC5B and MUC7 mucins from saliva of HIV negative individuals inhibit HIV-1 activity by 100% in an in vitro assay. The purpose of this subsequent study was to investigate whether MUC5B and MUC7 from saliva of HIV patients or with full blown AIDS had a similar inhibitory activity against the virus. Methods Salivary MUC5B and MUC7 from HIV patients with different CD4 counts (< 200, 200-400 and > 400) were incubated with HIV-1 prior to infection of the human T lymphoblastoid cell line (CEM SS cells). Cells were then cultured and viral replication was measured by a qualitative p24 antigen assay. The size, charge and immunoreactivity of mucins from HIV negative and positive individuals was also analysed by SDS-PAGE, Western blot and ELISA respectively. Results: It was shown that irrespective of their CD4 counts both MUC5B and MUC7 from HIV patients, unlike the MUC5B and MUC7 from HIV negative individuals, did not inhibit HIV-1 activity. Size, charge and immunoreactivity differences between the mucins from HIV negative and positive individuals and among the mucins from HIV patients of different CD4 count was observed by SDS-PAGE, Western blot and ELISA. Conclusions: Purified salivary mucins from HIV positive patients do not inhibit the AIDS virus in an in vitro assay. Although the reason for the inability of mucins from infected individuals to inhibit the virus is not known, it is likely that there is an alteration of the glycosylation pattern, and therefore of charge of mucin, in HIV positive patients. The ability to inhibit the virus by aggregation by sugar chains is thus diminished.
Antibody responses to vaccination among South African HIV-exposed and unexposed uninfected infants during the first 2 years of life
(American Society for Microbiology, 2013-01) Reikie, Brian A.; Naidoo, Shalena; Ruck, Candice E.; Slogrove, Amy L.; De Beer, Corena; La Grange, Heleen; Adams, Rozanne C. M.; Ho, Kevin; Smolen, Kinga; Speert, David P.; Cotton, Mark F.; Preiser, Wolfgang; Esser, Monika; Kollmann, Tobias R.
HIV-exposed but uninfected (HEU) infants born to HIV-infected mothers from areas in the world with a high burden of infectious disease suffer higher infectious morbidity and mortality than their HIV unexposed uninfected (HUU) peers. Vaccination provides protection from infection. The possibility exists that altered response to vaccination contributes to the higher rate of infection in HEU than in HUU infants. While short-term, cross-sectional studies support this notion, it is unclear whether or not HEU infants develop long-term protective immune responses following theWHOextended program on immunization (EPI). Vaccine-specific antibody responses were compared between HEU and HUU infants from 2 weeks until 2 years of age in a longitudinal South African cohort. Total IgG and antibodies specific for Bordetella pertussis, Haemophilus influenzae type b (Hib), tetanus toxoid, hepatitis B virus (HepB), and measles virus were measured at multiple time points throughout the first 2 years of life. Prevaccine antibodies (maternal antibodies passively acquired) specific for tetanus were lower in HEU than in HUU infants, while prevaccine antibodies to HepB were higher in HEU than in HUU infants. Both groups responded similarly to tetanus, Hib, and HepB vaccination. HEU demonstrated stronger pertussis vaccine responses, developing protective titers 1 year earlier than HUU patients, and maintained higher anti-tetanus titers at 24 months of age. Vaccine-induced antibodies to measles virus were similar in both groups at all time points. Our results suggest that the current EPI vaccination program as practiced in South Africa leads to the development of vaccine-specific antibody responses that are equivalent in HEU and HUU infants. However, our data also suggest that a large fraction of both HEU and HUU South African infants have antibody titers for several infectious threats that remain below the level of protection for much of their first 2 years of life.
Barriers to HIV remission research in low- and middle-income countries
(Wiley Open Access, 2017) Rossouw, Theresa; Tucker, Joseph D.; Van Zyl, Gert U.; Sikwesi, Kenly; Godfrey, Catherine
Introduction: HIV eradication and remission research has largely taken place in high-income countries. In low- and middleincome countries (LMIC), there may be factors that have a substantial impact on the size of the latent HIV reservoir and the immunological response to infection. If a curative strategy is to be available to all HIV-infected individuals, these factors must be understood. Methods: We use a scoping review to examine the literature on biological factors that may have an impact on HIV persistence in LMIC. Three databases were searched without date restrictions. Results: Uncontrolled viral replication and higher coinfection prevalence may alter the immunological milieu of individuals in LMIC and increase the size of the HIV reservoir. Differences in HIV subtype could also influence the measurement and size of the HIV reservoir. Immune activation may differ due to late presentation to care, presence of chronic infections, increased gut translocation of bacterial products and poor nutrition. Conclusions: Research on HIV remission is urgently needed in LMIC. Research into chronic immune activation in resource poor environments, the immune response to infection, the mechanisms of HIV persistence and latency in different viral clades and the effect of the microbiological milieu must be performed. Geographic differences, which may be substantial and may delay access to curative strategies, should be identified.
Barriers to VCT despite 13 years of community-based awareness campaigns in a peri-urban township in northern Limpopo
(Health and Medical Publishing Group (HMPG), 2010) De Koker, Petra; Lefevre, Pierre; Matthys, Francine; Van der Stuyft, Patrick; Delva, Wim
Bimodal distribution and set point HBV DNA viral loads in chronic infection : retrospective analysis of cohorts from the UK and South Africa
(Wellcome Open Research, 2020-10-14) Downs, Louise O.; Vawda, Sabeehah; Bester, Phillip Armand; Lythgoe, Katrina A.; Wang, Tingyan; McNaughton, Anna L.; Smith, David A.; Maponga, Tongai; Freeman, Oliver; Várnai, Kinga A.; Davies, Jim; Woods, Kerrie; Fraser, Christophe; Barnes, Eleanor; Goedhals, Dominique; Matthews, Philippa C.
ENGLISH ABSTRACT: Hepatitis B virus (HBV) viral load (VL) is used as a biomarker to assess risk of disease progression, and to determine eligibility for treatment. While there is a well recognised association between VL and the expression of the viral e-antigen protein, the distributions of VL at a population level are not well described. We here present cross-sectional, observational HBV VL data from two large population cohorts in the UK and in South Africa, demonstrating a consistent bimodal distribution. The right skewed distribution and low median viral loads are different from the left-skew and higher viraemia in seen in HIV and hepatitis C virus (HCV) cohorts in the same settings. Using longitudinal data, we present evidence for a stable 'set-point' VL in peripheral blood during chronic HBV infection. These results are important to underpin improved understanding of HBV biology, to inform approaches to viral sequencing, and to plan public health interventions.
Biomedical research and capacity building : bilateral collaboration between research institutes in South Africa and Cameroon
(Health & Medical Publishing Group, 2016) Jacobs, Graeme Brendon; Ikomey, G. M.
No abstract available
Candida species : species distribution and antifungal susceptibility patterns
(Health and Medical Publishing Group (HMPG), 2008) Arendse, Tracy; Orth, Heidi
[No abstract available]
Clinical relevance of total HIV DNA in peripheral blood mononuclear cell compartments as a biomarker of HIV-associated neurocognitive
(MDPI, 2017-10-31) Ruhanya, Vurayai; Jacobs, Graeme Brendon; Glashoff, Richard H.; Engelbrecht, Susan
ENGLISH ABSTRACT: The pathogenesis of HIV-associated neurocognitive disorders is complex and multifactorial. It is hypothesized that the critical events initiating this condition occur outside the brain, particularly in the peripheral blood. Diagnoses of HIV-induced neurocognitive disorders largely rely on neuropsychometric assessments, which are not precise. Total HIV DNA in the peripheral blood mononuclear cells (PBMCs), quantified by PCR, correlate with disease progression, which is a promising biomarker to predict HAND. Numerous PCR assays for HIV DNA in cell compartments are prone to variation due to the lack of standardization and, therefore, their utility in predicting HAND produced different outcomes. This review evaluates the clinical relevance of total HIV DNA in circulating mononuclear cells using different published quantitative PCR (qPCR) protocols. The rationale is to shed light on the most appropriate assays and sample types used to accurately quantify HIV DNA load, which predicts severity of neurocognitive impairment. The role of monocytes as a vehicle for trafficking HIV into the CNS makes it the most suitable sample for determining a HAND associated reservoir. Studies have also shown significant associations between monocyte HIV DNA levels with markers of neurodamage. However, qPCR assays using PBMCs are cheaper and available commercially, thus could be beneficial in clinical settings. There is need, however, to standardise DNA extraction, normalisation and limit of detection.
Close Relative of Human Middle East Respiratory Syndrome Coronavirus in Bat, South Africa
(Centers for Disease Control and Prevention (CDC), 2013-10) Ithete, Ndapewa Laudika; Stoffberg, Samantha; Corman, Victor Max; Cottontail, Veronika M.; Richards, Leigh Rosanne; Schoeman, M. Corrie; Drosten, Christian; Drexler, Jan Felix; Preiser, Wolfgang
We now report the identification of a South Africa bat derived CoV that has an even closer phylogenetic relationship with MERS-CoV.
Collaborative update of a rule-based expert system for HIV-1 genotypic resistance test interpretation
(Public Library of Science, 2017-07-28) Paredes, Roger; Tzou, Philip L.; Van Zyl, Gert; Barrow, Geoff; Camacho, Ricardo; Carmona, Sergio; Grant, Philip M.; Gupta, Ravindra K.; Hamers, Raph L.; Harrigan, P. Richard; Jordan, Michael R.; Kantor, Rami; Katzenstein, David A.; Kuritzkes, Daniel R.; Maldarelli, Frank; Otelea, Dan; Wallis, Carole L.; Schapiro, Jonathan M.; Shafer, Robert W.
Introduction: HIV-1 genotypic resistance test (GRT) interpretation systems (IS) require updates as new studies on HIV-1 drug resistance are published and as treatment guidelines evolve. Methods: An expert panel was created to provide recommendations for the update of the Stanford HIV Drug Resistance Database (HIVDB) GRT-IS. The panel was polled on the ARVs to be included in a GRT report, and the drug-resistance interpretations associated with 160 drug-resistance mutation (DRM) pattern-ARV combinations. The DRM pattern-ARV combinations included 52 nucleoside RT inhibitor (NRTI) DRM pattern-ARV combinations (13 patterns x 4 NRTIs), 27 nonnucleoside RT inhibitor (NNRTI) DRM pattern-ARV combinations (9 patterns x 3 NNRTIs), 39 protease inhibitor (PI) DRM pattern-ARV combinations (13 patterns x 3 PIs) and 42 integrase strand transfer inhibitor (INSTI) DRM pattern-ARV combinations (14 patterns x 3 INSTIs). Results: There was universal agreement that a GRT report should include the NRTIs lamivudine, abacavir, zidovudine, emtricitabine, and tenofovir disoproxil fumarate; the NNRTIs efavirenz, etravirine, nevirapine, and rilpivirine; the PIs atazanavir/r, darunavir/r, and lopinavir/r (with “/r” indicating pharmacological boosting with ritonavir or cobicistat); and the INSTIs dolutegravir, elvitegravir, and raltegravir. There was a range of opinion as to whether the NRTIs stavudine and didanosine and the PIs nelfinavir, indinavir/r, saquinavir/r, fosamprenavir/r, and tipranavir/r should be included. The expert panel members provided highly concordant DRM pattern-ARV interpretations with only 6% of NRTI, 6% of NNRTI, 5% of PI, and 3% of INSTI individual expert interpretations differing from the expert panel median by more than one resistance level. The expert panel median differed from the HIVDB 7.0 GRT-IS for 20 (12.5%) of the 160 DRM pattern-ARV combinations including 12 NRTI, two NNRTI, and six INSTI pattern-ARV combinations. Eighteen of these differences were updated in HIVDB 8.1 GRT-IS to reflect the expert panel median. Additionally, HIVDB users are now provided with the option to exclude those ARVs not considered to be universally required. Conclusions: The HIVDB GRT-IS was updated through a collaborative process to reflect changes in HIV drug resistance knowledge, treatment guidelines, and expert opinion. Such a process broadens consensus among experts and identifies areas requiring further study.
Construction of a high titer infectious HIV-1 subtype C proviral clone from South Africa
(MDPI, 2012-09-24) Jacobs, Graeme Brendon; Bock, Stefanie; Schuch, Anita; Moschall, Rebecca; Schrom, Eva-Maria; Zahn, Juliane; Reuter, Christian; Preiser, Wolfgang; Rethwilm, Axel; Engelbrecht, Susan; Kerkau, Thomas; Bodem, Jochen
The Human Immunodeficiency Virus type 1 (HIV-1) subtype C is currently the predominant subtype worldwide. Cell culture studies of Sub-Saharan African subtype C proviral plasmids are hampered by the low replication capacity of the resulting viruses, although viral loads in subtype C infected patients are as high as those from patients with subtype B. Here, we describe the sequencing and construction of a new HIV-1 subtype C proviral clone (pZAC), replicating more than one order of magnitude better than the previous subtype C plasmids. We identify the env-region for being the determinant for the higher viral titers and the pZAC Env to be M-tropic. This higher replication capacity does not lead to a higher cytotoxicity compared to previously described subtype C viruses. In addition, the pZAC Vpu is also shown to be able to down-regulate CD4, but fails to fully counteract CD317.
COVID-19 : getting ahead of the epidemic curve by early implementation of social distancing
(Health & Medical Publishing Group, 2020) Preiser, Wolfgang; Van Zyl, Gert; Dramowski, Angela
The response to the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), has largely been reactive. There are a few exceptions of countries taking proactive measures. Some countries in Asia, including Taiwan and Singapore, were able to limit the spread despite close links to China,[1,2] and South Korea and China were able to mobilise to contain an initial rapidly spreading epidemic through mass testing and early interventions.[2,3] As COVID-19 has now reached Africa, South Africa (SA) could be a regional leader in its response and reduce the impact of the disease on its population by acting early.
Deciphering multiplicity of HIV-1C infection : transmission of closely related multiple viral lineages
(Public Library of Science, 2016-11-28) Novitsky, Vlad; Moyo, Sikhulile; Wang, Rui; Gaseitsiwe, Simani; Essex, M.
Background: A single viral variant is transmitted in the majority of HIV infections. However, about 20% of heterosexually transmitted HIV infections are caused by multiple viral variants. Detection of transmitted HIV variants is not trivial, as it involves analysis of multiple viral sequences representing intra-host HIV-1 quasispecies. Methodology: We distinguish two types of multiple virus transmission in HIV infection: (1) HIV transmission from the same source, and (2) transmission from different sources. Viral sequences representing intra-host quasispecies in a longitudinally sampled cohort of 42 individuals with primary HIV-1C infection in Botswana were generated by single-genome amplification and sequencing and spanned the V1C5 region of HIV-1C env gp120. The Maximum Likelihood phylogeny and distribution of pairwise raw distances were assessed at each sampling time point (n = 217; 42 patients; median 5 (IQR: 4–6) time points per patient, range 2–12 time points per patient). Results: Transmission of multiple viral variants from the same source (likely from the partner with established HIV infection) was found in 9 out of 42 individuals (21%; 95 CI 10–37%). HIV super-infection was identified in 2 patients (5%; 95% CI 1–17%) with an estimated rate of 3.9 per 100 person-years. Transmission of multiple viruses combined with HIV super-infection at a later time point was observed in one individual. Conclusions: Multiple HIV lineages transmitted from the same source produce a monophyletic clade in the inferred phylogenetic tree. Such a clade has transiently distinct sub-clusters in the early stage of HIV infection, and follows a predictable evolutionary pathway. Over time, the gap between initially distinct viral lineages fills in and initially distinct sub-clusters converge. Identification of cases with transmission of multiple viral lineages from the same source needs to be taken into account in cross-sectional estimation of HIV recency in epidemiological and population studies
Delays in HIV-1 infant polymerase chain reaction testing may leave children without confirmed diagnoses in the Western Cape province, South Africa
(AOSIS, 2022-06) Mahlakwane, Kamela L.; Preiser, Wolfgang; Nkosi, Nokwazi; Naidoo, Nasheen; Van Zyl, Gert
Background: Early diagnosis and confirmation of HIV infection in newborns is crucial for expedited initiation of antiretroviral therapy. Confirmatory testing must be done for all children with a reactive HIV PCR result. There is no comprehensive data on confirmatory testing and HIV PCR test request rejections at National Health Laboratory Service laboratories in South Africa. Objective: This study assessed the metrics of routine infant HIV PCR testing at the Tygerberg Hospital Virology Laboratory, Cape Town, Western Cape, South Africa, including the proportion of rejected test requests, turn-around time (TAT), and rate of confirmatory testing. Methods: We retrospectively reviewed laboratory-based data on all HIV PCR tests performed on children ≤ 24 months old (n = 43 346) and data on rejected HIV PCR requests (n = 1479) at the Tygerberg virology laboratory over two years (2017–2019). Data from sample collection to release of results were analysed to assess the TAT and follow-up patterns. Results: The proportion of rejected HIV PCR requests was 3.3%; 83.9% of these were rejected for various pre-analytical reasons. Most of the test results (89.2%) met the required 96-h TAT. Of the reactive initial test results, 53.5% had a follow-up sample tested, of which 93.1% were positive. Of the initial indeterminate results, 74.7% were negative on follow-up testing. Conclusion: A high proportion of HIV PCR requests were rejected for pre-analytical reasons. The high number of initial reactive tests without evidence of follow-up suggests that a shorter TAT is required to allow confirmatory testing before children are discharged.
Detectable HIV-1 in semen in individuals with very low blood viral loads
(BioMed Central, 2020-03-05) Kariuki, Samuel Mundia; Selhorst, Philippe; Norman, Jennifer; Cohen, Karen; Rebe, Kevin; Williamson, Carolyn; Dorfman, Jeffrey R
Background: Several reports indicate that a portion (5–10%) of men living with HIV-1 intermittently shed HIV-1 RNA into seminal plasma while on long term effective antiretroviral therapy (ART). This is highly suggestive of an HIV-1 reservoir in the male genital tract. However, the status of this reservoir in men living with HIV-1 who are not under treatment is underexplored and has implications for understanding the origins and evolution of the reservoir. Finding: Forty-three HIV-1 positive, antiretroviral therapy naïve study participants attending a men’s health clinic were studied. Semen viral loads and blood viral loads were generally correlated, with semen viral loads generally detected in individuals with blood viral loads > 10,000 cp/ml. However, we found 1 individual with undetectable viral loads (<20cp/ml) and 2 individuals with very low blood viral load (97 and 333cp/ml), but with detectable HIV-1 in semen (485–1157 copies/ semen sample). Blood viral loads in the first individual were undetectable when tested three times over the prior 5 years. Conclusions: Semen HIV-1 viral loads are usually related to blood viral loads, as we confirm. Nonetheless, this was not true in a substantial minority of individuals suggesting unexpectedly high levels of replication in the male genital tract in a few individuals, despite otherwise effective immune control. This may reflect establishment of a local reservoir of HIV-1 populations.

Browse

Browsing Research Articles (Medical Virology) by Title

Results Per Page

Sort Options