Research Articles (Medical Virology)
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- ItemNanoHIV: a bioinformatics pipeline for producing accurate, near full-length HIV proviral genomes sequenced using the Oxford Nanopore technology(MDPI, 2021-09) Wright, Imogen A.; Delaney, Kayla E.; Katusiime, Mary Grace K.; Botha, Johannes C.; Engelbrecht, SusanHIV-1 proviral single-genome sequencing by limiting-dilution polymerase chain reaction (PCR) amplification is important for differentiating the sequence-intact from defective proviruses that persist during antiretroviral therapy (ART). Intact proviruses may rebound if ART is interrupted and are the barrier to an HIV cure. Oxford Nanopore Technologies (ONT) sequencing offers a promising, cost-effective approach to the sequencing of long amplicons such as near full-length HIV-1 proviruses, but the high diversity of HIV-1 and the ONT sequencing error render analysis of the generated data difficult. NanoHIV is a new tool that uses an iterative consensus generation approach to construct accurate, near full-length HIV-1 proviral single-genome sequences from ONT data. To validate the approach, single-genome sequences generated using NanoHIV consensus building were compared to Illumina® consensus building of the same nine single-genome near full-length amplicons and an average agreement of 99.4% was found between the two sequencing approaches.
- ItemElucidation of early evolution of HIV-1 GroupM in the Congo Basin using computational methods(MDPI, 2021-04) Tongo, Marcel; Martin, Darren P.; Dorfman, Jeffrey R.The Congo Basin region is believed to be the site of the cross-species transmission event that yielded HIV-1 group M (HIV-1M). It is thus likely that the virus has been present and evolving in the region since that cross-species transmission. As HIV-1M was only discovered in the early 1980s, our directly observed record of the epidemic is largely limited to the past four decades. Nevertheless, by exploiting the genetic relatedness of contemporary HIV-1M sequences, phylogenetic methods provide a powerful framework for investigating simultaneously the evolutionary and epidemiologic history of the virus. Such an approach has been taken to find that the currently classified HIV-1 M subtypes and Circulating Recombinant Forms (CRFs) do not give a complete view of HIV-1 diversity. In addition, the currently identified major HIV-1M subtypes were likely genetically predisposed to becoming a major component of the present epidemic, even before the events that resulted in the global epidemic. Further efforts have identified statistically significant hot- and cold-spots of HIV-1M subtypes sequence inheritance in genomic regions of recombinant forms. In this review we provide ours and others recent findings on the emergence and spread of HIV-1M variants in the region, which have provided insights into the early evolution of this virus.
- ItemMolecular characterisation and epidemiology of enterovirus-associated aseptic meningitis in the Western and Eastern Cape Provinces, South Africa 2018–2019(Elsevier B.V., 2021-04) Nkosi, Nokwazi; Preiser, Wolfgang; Van Zyl, Gert; Claassen, Mathilda; Cronje, Nadine; Maritz, Jean; Newman, Howard; McCarthy, Kerrigan; Ntshoe, Genevie; Essel, Vivien; Korsman, Stephen; Hardie, Diana; Smuts, HeidiBackground: Enteroviruses are amongst the most common causes of aseptic meningitis. Between November 2018 and May 2019, an outbreak of enterovirus-associated aseptic meningitis cases was noted in the Western and Eastern Cape Provinces, South Africa. Objectives: To describe the epidemiology and phylogeography of enterovirus infections during an aseptic meningitis outbreak in the Western and Eastern Cape Provinces of South Africa. Methods: Cerebrospinal fluid samples from suspected cases were screened using a polymerase chain reaction targeting the 5’UTR. Confirmed enterovirus-associated meningitis samples underwent molecular typing through species–specific VP1/VP2 primers and pan-species VP1 primers. Results: Between November 2018 and May 2019, 3497 suspected cases of aseptic meningitis were documented in the Western and Eastern Cape Provinces. Median age was 8 years (range 0–61), interquartile range (IQR=4–13 years), 405/735 (55%) male. 742/3497 (21%) cases were laboratory – confirmed enterovirus positive by routine diagnostic PCR targeting the 5’UTR. 128/742 (17%) underwent molecular typing by VP1 gene sequencing. Echovirus 4 (E4) was detected in 102/128 (80%) cases. Echovirus 9 was found in 7%, Coxsackievirus A13 in 3%. 10 genotypes contributed to the remaining 10% of cases. Synonymous mutations were found in most cases, with sporadic amino acid changes in 13 (12.7%) cases. Conclusion: The aseptic meningitis outbreak was associated with echovirus 4. Stool samples are valuable for molecular typing in CSF confirmed EV-associated aseptic meningitis.
- ItemPeripheral blood lymphocyte proviral DNA predicts neurocognitive impairment in clade C HIV(Springer, 2020-07) Ruhanya, Vurayai; Jacobs, Graeme Brendon; Nyandoro, George; Paul, Robert H.; Joska, John A.; Seedat, Soraya; Glashoff, Richard Helmuth; Engelbrecht, SusanIt is not known if proviral DNA in the periphery corresponds to cognitive status in clade C as it does in clade B and recombinant forms. A cross-sectional study was conducted on participants investigated for HIV-associated neurocognitive impairment in South Africa. HIV-1 proviral DNA was quantified using a PCR assay targeting a highly conserved HIV-1 LTR-gag region. Fifty-four (36.7%) participants were cognitively impaired and 93 (63.3%) were not impaired. Forty-three (79.6%) of the cognitively impaired participants were female and 11 (20.4%) were male. There was no significant age difference between cognitively impaired and unimpaired participants (p = 0.42). HIV-1 DNA in cognitively impaired PLWH was significantly higher than in cognitively normal individuals (p = .016). Considering impaired participants, lymphocyte HIV-1 DNA was significantly higher in males than females (p = 0.02). There was a modest positive correlation between lymphocyte HIV-1 DNA and global deficit scores (GDS) r = 0.176; p = 0.03). The two measures of viral load, lymphocyte HIV-1 DNA copies/million and plasma RNA copies/ml, were positively correlated (r = 0.39; p < .001). After adjusting for other covariates, age, sex, treatment status, and the interactions between impairment and treatment, the multivariate regression showed association between proviral load and neurocognitive impairment; omega effect size was 0.04, p value = 0.010. The burden of HIV-1 peripheral blood lymphocyte proviral DNA corresponds to neurocognitive impairment among individuals infected with clade C disease. Therefore, therapeutic strategies to reduce the HIV-1 proviral DNA reservoir in lymphocytes may improve neurocognitive outcomes in PLWH.
- ItemDelays 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, GertBackground: 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.