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1.
J Pers Med ; 14(6)2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38929796

RESUMO

Lynch syndrome (LS) is an inherited cancer predisposition disorder associated with an elevated risk of developing various solid cancers, but mostly colorectal cancer (CRC). Despite having the same germline pathogenic variant (PV) in one of the mis-match repair genes or the EPCAM gene, Lynch syndrome variant heterozygotes (LSVH) exhibit a remarkable phenotypic variability in the risk of developing cancer. The role of human leukocyte antigen (HLA) in modifying cancer development risk prompted our hypothesis into whether HLA variations act as potential genetic modifiers influencing the age at cancer diagnosis in LSVH. To investigate this, we studied a unique cohort of 426 LSVH carrying the same germline PV in the hMLH1 gene (MLH1:c.1528C > T) in South Africa. We intuitively selected 100 LSVH with the greatest diversity in age at cancer diagnosis (N = 80) and the oldest cancer unaffected LSVH (N = 20) for a high-throughput HLA genotyping of 11 HLA class I and class II loci using the shotgun next-generation sequencing (NGS) technique on the Illumina MiSeq platform. Statistical analyses employed Kaplan-Meier survival analyses with log-rank tests, and Cox proportional hazards using binned HLA data to minimize type I error. Significant associations were observed between young age at cancer diagnosis and HLA-DPB1*04:02 (mean age: 37 y (25-50); hazard ratio (HR) = 3.37; corrected p-value (q) = 0.043) as well as HLA-DPB1 binned alleles (including HLA-DPB1*09:01, HLA-DPB1*10:01, HLA-DPB1*106:01, HLA-DPB1*18:01, HLA-DPB1*20:01, HLA-DPB1*26:01, HLA-DPB1*28:01, HLA-DPB1*296:01, and HLA-DPB1*55:01) (mean age: 37 y (17-63); HR = 2.30, q = 0.045). The involvement of HLA-DPB1 alleles in the age at cancer diagnosis may highlight the potential role of HLA class II in the immune response against cancer development in LSVH. When validated in a larger cohort, these high-risk HLA-DPB1 alleles could be factored into cancer risk prediction models for personalized cancer screening in LSVH.

3.
Diagnostics (Basel) ; 13(15)2023 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-37568938

RESUMO

The epidemiology of human parainfluenza viruses (HPIV), particularly its role as a cause of acute respiratory infection (ARI) in infants, has not been formally studied in South Africa. We evaluated HPIV prevalence in diagnostic samples from hospitalized children from public sector hospitals in the Western Cape between 2014 and 2022. HPIV infection was detected in 2-10% of patients, with the majority of infections detected in children less than 1 year of age. Prior to 2020, HPIV 4 (40%) and HPIV 3 (34%) were the most prevalent types, with seasonal peaks in late winter/spring for HPIV 3 and autumn/winter for HPIV 4. HPIV 4A and 4B co-circulated during the seasonal activity between 2014 and 2017. Pandemic restrictions in 2020 had a profound effect on HPIV circulation and the rebound was dominated by waves of HPIV 3, accounting for 66% of detections and a sustained decline in the circulation of HPIV 1, 2 and 4. An immunity gap could account for the surge in HPIV 3 infections, but the decline in prior HPIV 4 dominance is unexplained and requires further study.

4.
Int J Infect Dis ; 118: 150-154, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35235826

RESUMO

BACKGROUND: At present, it is unclear whether the extent of reduced risk of severe disease seen with SARS-Cov-2 Omicron variant infection is caused by a decrease in variant virulence or by higher levels of population immunity. METHODS: RdRp target delay (RTD) in the Seegene AllplexTM 2019-nCoV PCR assay is a proxy marker for the Delta variant. The absence of this proxy marker in the transition period was used to identify suspected Omicron infections. Cox regression was performed for the outcome of hospital admission in those who tested positive for SARS-CoV-2 on the Seegene AllplexTM assay from November 1 to December 14, 2021 in the Western Cape Province, South Africa, in the public sector. Adjustments were made for vaccination status and prior diagnosis of infection. RESULTS: A total of 150 cases with RTD and 1486 cases without RTD were included. Cases without RTD had a lower hazard of admission (adjusted hazard ratio [aHR], 0.56; 95% confidence interval [CI], 0.34-0.91). Complete vaccination was protective against admission, with an aHR of 0.45 (95% CI, 0.26-0.77). CONCLUSION: Omicron has resulted in a lower risk of hospital admission compared with contemporaneous Delta infection, when using the proxy marker of RTD. Under-ascertainment of reinfections with an immune escape variant remains a challenge to accurately assessing variant virulence.


Assuntos
COVID-19 , Hepatite D , COVID-19/diagnóstico , Humanos , Reação em Cadeia da Polimerase , RNA Polimerase Dependente de RNA , SARS-CoV-2/genética , África do Sul/epidemiologia , Análise de Sobrevida
5.
J Virol Methods ; 302: 114471, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35051442

RESUMO

Routine SARS-CoV-2 surveillance in the Western Cape region of South Africa (January-August 2021) found a reduced RT-PCR amplification efficiency of the RdRp-gene target of the Seegene, Allplex 2019-nCoV diagnostic assay from June 2021 when detecting the Delta variant. We investigated whether the reduced amplification efficiency denoted by an increased RT-PCR cycle threshold value (RΔE) can be used as an indirect measure of SARS-CoV-2 Delta variant prevalence. We found a significant increase in the median RΔE for patient samples tested from June 2021, which coincided with the emergence of the SARS-CoV-2 Delta variant within our sample set. Whole genome sequencing on a subset of patient samples identified a highly conserved G15451A, non-synonymous mutation exclusively within the RdRp gene of Delta variants, which may cause reduced RT-PCR amplification efficiency. While whole genome sequencing plays an important in identifying novel SARS-CoV-2 variants, monitoring RΔE value can serve as a useful surrogate for rapid tracking of Delta variant prevalence.


Assuntos
Teste de Ácido Nucleico para COVID-19 , COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , COVID-19/virologia , Testes Diagnósticos de Rotina , Humanos , RNA , RNA Polimerase Dependente de RNA , SARS-CoV-2/genética
6.
Gates Open Res ; 6: 117, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-37994361

RESUMO

Background: The SARS-CoV-2 Delta variant (B.1.617.2) has been associated with more severe disease, particularly when compared to the Alpha variant. Most of this data, however, is from high income countries and less is understood about the variant's disease severity in other settings, particularly in an African context, and when compared to the Beta variant. Methods: A novel proxy marker, RNA-dependent RNA polymerase (RdRp) target delay in the Seegene Allplex TM 2019-nCoV (polymerase chain reaction) PCR assay, was used to identify suspected Delta variant infection in routine laboratory data. All cases diagnosed on this assay in the public sector in the Western Cape, South Africa, from 1 April to 31 July 2021, were included in the dataset provided by the Western Cape Provincial Health Data Centre (PHDC). The PHDC collates information on all COVID-19 related laboratory tests, hospital admissions and deaths for the province. Odds ratios for the association between the proxy marker and death were calculated, adjusted for prior diagnosed infection and vaccination status. Results: A total of 11,355 cases with 700 deaths were included in this study. RdRp target delay (suspected Delta variant) was associated with higher mortality (adjusted odds ratio [aOR] 1.45; 95% confidence interval [CI]: 1.13-1.86), compared to presumptive Beta infection. Prior diagnosed infection during the previous COVID-19 wave, which was driven by the Beta variant, was protective (aOR 0.32; 95%CI: 0.11-0.92) as was vaccination (aOR [95%CI] 0.15 [0.03-0.62] for complete vaccination [≥28 days post a single dose of Ad26.COV2.S or ≥14 days post second BNT162b2 dose]). Conclusion: RdRp target delay, a proxy for infection with the Delta variant, is associated with an increased risk of mortality amongst those who were tested for COVID-19 in our setting.

7.
Influenza Other Respir Viruses ; 16(2): 222-235, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34528769

RESUMO

BACKGROUND: We aimed to describe the prevalence of human respiratory syncytial virus (HRSV) and evaluate associations between HRSV subgroups and/or genotypes and epidemiologic characteristics and clinical outcomes in patients hospitalized with severe respiratory illness (SRI). METHODS: Between January 2012 and December 2015, we enrolled patients of all ages admitted to two South African hospitals with SRI in prospective hospital-based syndromic surveillance. We collected respiratory specimens and clinical and epidemiological data. Unconditional random effect multivariable logistic regression was used to assess factors associated with HRSV infection. RESULTS: HRSV was detected in 11.2% (772/6908) of enrolled patients of which 47.0% (363/772) were under the age of 6 months. There were no differences in clinical outcomes of HRSV subgroup A-infected patients compared with HRSV subgroup B-infected patients but among patients aged <5 years, children with HRSV subgroup A were more likely be coinfected with Streptococcus pneumoniae (23/208, 11.0% vs. 2/90, 2.0%; adjusted odds ratio 5.7). No significant associations of HRSV A genotypes NA1 and ON1 with specific clinical outcomes were observed. CONCLUSIONS: While HRSV subgroup and genotype dominance shifted between seasons, we showed similar genotype diversity as noted worldwide. We found no association between clinical outcomes and HRSV subgroups or genotypes.


Assuntos
Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Criança , Genótipo , Humanos , Lactente , Filogenia , Estudos Prospectivos , Infecções por Vírus Respiratório Sincicial/epidemiologia , Vírus Sincicial Respiratório Humano/genética , África do Sul/epidemiologia
8.
Sci Transl Med ; 14(631): eabj6824, 2022 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-34931886

RESUMO

SARS-CoV-2 variants that escape neutralization and potentially affect vaccine efficacy have emerged. T cell responses play a role in protection from reinfection and severe disease, but the potential for spike mutations to affect T cell immunity is incompletely understood. We assessed neutralizing antibody and T cell responses in 44 South African COVID-19 patients either infected with the Beta variant (dominant from November 2020 to May 2021) or infected before its emergence (first wave, Wuhan strain) to provide an overall measure of immune evasion. We show that robust spike-specific CD4 and CD8 T cell responses were detectable in Beta-infected patients, similar to first-wave patients. Using peptides spanning the Beta-mutated regions, we identified CD4 T cell responses targeting the wild-type peptides in 12 of 22 first-wave patients, all of whom failed to recognize corresponding Beta-mutated peptides. However, responses to mutated regions formed only a small proportion (15.7%) of the overall CD4 response, and few patients (3 of 44) mounted CD8 responses that targeted the mutated regions. Among the spike epitopes tested, we identified three epitopes containing the D215, L18, or D80 residues that were specifically recognized by CD4 T cells, and their mutated versions were associated with a loss of response. This study shows that despite loss of recognition of immunogenic CD4 epitopes, CD4 and CD8 T cell responses to Beta are preserved overall. These observations may explain why several vaccines have retained the ability to protect against severe COVID-19 even with substantial loss of neutralizing antibody activity against Beta.


Assuntos
COVID-19 , SARS-CoV-2 , Anticorpos Antivirais , Epitopos , Humanos , Glicoproteína da Espícula de Coronavírus/genética
9.
HLA ; 97(2): 173-174, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33219591

RESUMO

HLA-DQB1*05:272 has a single transversion compared to the most similar variant, HLA-DQB1*05:01:01 in IPD-IMGT/HLA database.


Assuntos
Cadeias beta de HLA-DQ , Alelos , Cadeias beta de HLA-DQ/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , África do Sul
10.
PLoS One ; 15(10): e0241029, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33079951

RESUMO

The SARS-CoV-2 pandemic has resulted in shortages of both critical reagents for nucleic acid purification and highly trained staff as supply chains are strained by high demand, public health measures and frequent quarantining and isolation of staff. This created the need for alternate workflows with limited reliance on specialised reagents, equipment and staff. We present here the validation and implementation of such a workflow for preparing samples for downstream SARS-CoV-2 RT-PCR using liquid handling robots. The rapid sample preparation technique evaluated, which included sample centrifugation and heating prior to RT-PCR, showed a 97.37% (95% CI: 92.55-99.28%) positive percent agreement and 97.30% (95% CI: 90.67-99.52%) negative percent agreement compared to nucleic acid purification-based testing. This method was subsequently adopted as the primary sample preparation method in the Groote Schuur Hospital Virology Diagnostic Laboratory in Cape Town, South Africa.


Assuntos
Betacoronavirus/genética , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/epidemiologia , Laboratórios Hospitalares , Pneumonia Viral/diagnóstico , Pneumonia Viral/epidemiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Robótica/métodos , COVID-19 , Teste para COVID-19 , Infecções por Coronavirus/virologia , Humanos , Pandemias , Pneumonia Viral/virologia , RNA Viral/genética , Reprodutibilidade dos Testes , SARS-CoV-2 , Sensibilidade e Especificidade , África do Sul/epidemiologia , Manejo de Espécimes
11.
Influenza Other Respir Viruses ; 14(3): 266-273, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32058677

RESUMO

BACKGROUND: In June 2017, an outbreak of the highly pathogenic avian influenza A(H5N8) was detected in commercial poultry farms in South Africa, which rapidly spread to all nine South African provinces. OBJECTIVES: We conducted active surveillance for the transmission of influenza A(H5N8) to humans working with infected birds during the South African outbreak. METHODS: Influenza A(H5N8)-positive veterinary specimens were used to evaluate the ability of real-time PCR-based assays to detect contemporary avian influenza A(H5N8) strains. Whole genome sequences were generated from these specimens by next-generation sequencing for phylogenetic characterization and screening for mammalian-adaptive mutations. RESULTS: Human respiratory samples from 74 individuals meeting our case definition, all tested negative for avian influenza A(H5) by real-time PCR, but 2 (3%) were positive for human influenza A(H3N2). 54% (40/74) reported wearing personal protective equipment including overalls, boots, gloves, masks, and goggles. 94% (59/63) of veterinary specimens positive for H5N8 were detected on an influenza A(H5) assay for human diagnostics. A commercial H5N8 assay detected H5 in only 6% (3/48) and N8 in 92% (44/48). Thirteen (13/25; 52%) A(H5N8) genomes generated from veterinary specimens clustered in a single monophyletic clade. These sequences contained the NS (P42S) and PB2 (L89V) mutations noted as markers of mammalian adaptation. CONCLUSIONS: Diagnostic assays were able to detect and characterize influenza A(H5N8) viruses, but poor performance is reported for a commercial assay. Absence of influenza A(H5N8) in humans with occupational exposure and no clear impression of molecular adaptation for mammalian infection suggest that this avian pathogen continues to be low-risk human pathogen.


Assuntos
Vírus da Influenza A Subtipo H5N8/genética , Influenza Aviária/virologia , Influenza Humana/virologia , Doenças das Aves Domésticas/virologia , Adolescente , Adulto , Animais , Animais Selvagens/virologia , Galinhas/virologia , Surtos de Doenças , Patos/virologia , Monitoramento Epidemiológico , Feminino , Gansos/virologia , Humanos , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza A Subtipo H5N8/classificação , Vírus da Influenza A Subtipo H5N8/isolamento & purificação , Influenza Aviária/epidemiologia , Influenza Humana/epidemiologia , Masculino , Pessoa de Meia-Idade , Filogenia , Doenças das Aves Domésticas/epidemiologia , África do Sul/epidemiologia , Struthioniformes/virologia , Adulto Jovem
12.
J Infect Dis ; 219(10): 1605-1615, 2019 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-30541140

RESUMO

BACKGROUND: We estimated the household secondary infection risk (SIR) and serial interval (SI) for influenza transmission from HIV-infected and HIV-uninfected index cases. METHODS: Index cases were the first symptomatic person in a household with influenza-like illness, testing influenza positive on real-time reverse transcription polymerase chain reaction (rRT-PCR). Nasopharyngeal swabs collected from household contacts every 4 days were tested by rRT-PCR. Factors associated with SIR were evaluated using logistic regression. RESULTS: We enrolled 28 HIV-infected and 57 HIV-uninfected index cases. On multivariable analysis, HIV-infected index cases were less likely to transmit influenza to household contacts (odds ratio [OR] 0.2; 95% confidence interval [CI], 0.1-0.6; SIR 16%, 18/113 vs 27%, 59/220). Factors associated with increased SIR included index age group 1-4 years (OR 3.6; 95% CI, 1.2-11.3) and 25-44 years (OR 8.0; 95% CI, 1.8-36.7), and contact age group 1-4 years (OR 3.5; 95% CI, 1.2-10.3) compared to 5-14 years, and sleeping with index case (OR 2.7; 95% CI, 1.3-5.5). HIV infection of index case was not associated with SI. CONCLUSIONS: HIV-infection was not associated with SI. Increased infectiousness of HIV-infected individuals is likely not an important driver of community influenza transmission.


Assuntos
Infecções por HIV/complicações , Influenza Humana/epidemiologia , Influenza Humana/transmissão , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Características da Família , Feminino , Infecções por HIV/epidemiologia , Humanos , Lactente , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza B/isolamento & purificação , Masculino , Pessoa de Meia-Idade , Fatores de Risco , África do Sul/epidemiologia , Adulto Jovem
13.
J Infect Dis ; 218(8): 1228-1237, 2018 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-29800425

RESUMO

Background: Prolonged shedding of influenza viruses may be associated with increased transmissibility and resistance mutation acquisition due to therapy. We compared duration and magnitude of influenza shedding between human immunodeficiency virus (HIV)-infected and -uninfected individuals. Methods: A prospective cohort study during 3 influenza seasons enrolled patients with influenza-like illness and a positive influenza rapid test. Influenza viruses were detected by real-time reverse transcription polymerase chain reaction. Weibull accelerated failure time regression models were used to describe influenza virus shedding. Mann-Whitney U tests explored initial influenza viral loads (VL). Results: Influenza virus shedding duration was similar in 65 HIV-infected (6 days; interquartile range [IQR] 3-10) and 176 HIV-uninfected individuals (7 days; IQR 4-11; P = .97), as was initial influenza VL (HIV-uninfected 5.28 ± 1.33 log10 copies/mL, HIV-infected 4.73 ± 1.68 log10 copies/mL; P = .08). Adjusted for age, HIV-infected individuals with low CD4 counts shed influenza virus for longer than those with higher counts (adjusted hazard ratio 3.55; 95% confidence interval, 1.05-12.08). Discussion: A longer duration of influenza virus shedding in HIV-infected individuals with low CD4 counts may suggest a possible increased risk for transmission or viral evolution in severely immunocompromised individuals. HIV-infected individuals should be prioritized for annual influenza immunization.


Assuntos
Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Influenza Humana/complicações , Influenza Humana/virologia , Orthomyxoviridae/fisiologia , Eliminação de Partículas Virais , Adolescente , Adulto , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Lactente , Influenza Humana/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , África do Sul/epidemiologia , Carga Viral , Adulto Jovem
14.
PLoS One ; 13(5): e0198101, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29795677

RESUMO

Limited information is available on influenza virus sequence drift between transmission events. In countries with high HIV burdens, like South Africa, the direct and indirect effect of HIV on influenza sequence drift between transmission events may be of public health concern. To this end, we measured hemagglutinin sequence diversity between influenza transmission events using data and specimens from a study investigating household transmission dynamics of seasonal influenza viruses in 2 peri-urban communities in South Africa during the 2013 influenza season. Thirty index cases and 107 of 110 eligible household contacts were enrolled into the study, 47% (14/30) demonstrating intra-household laboratory-confirmed influenza transmission. In this study 35 partial hemagglutinin gene sequences were obtained by Sanger sequencing from 11 index cases (sampled at enrolment only) and 16 secondary cases (8 cases sampled at 1 and 8 cases sampled at 2 time-points). Viral sequence identities confirmed matched influenza transmission pairs within the 11 households with corresponding sequenced index and secondary cases. Phylogenetic analysis revealed 10 different influenza viral lineages in the 14 households. Influenza A(H1N1)pdm09 strains were shown to be genetically distinct between the 2 communities (from distinct geographic regions), which was not observed for the influenza A(H3N2) strains. Intra-host/intra-household influenza A(H3N2) sequence drift was identified in 2 households. The first was a synonymous mutation between the index case and a household contact, and the second a non-synonymous mutation between 2 serial samples taken at days 0 and 4 post enrolment from an HIV-infected secondary case. Limited inter-household sequence diversity was observed as highlighted by sharing of the same influenza strain between different households within each community. The limited intra-household sequence drift is in line with previous studies also using Sanger sequencing, corroborating the presence of strict selective bottlenecks that limit sequence variance. We were not able to directly ascertain the effect of HIV on influenza sequence drift between transmission events.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vírus da Influenza A/classificação , Influenza Humana/transmissão , Influenza Humana/virologia , Características da Família , Variação Genética , Humanos , Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Influenza Humana/epidemiologia , Filogenia , RNA Viral/genética , Fatores de Risco , Análise de Sequência de DNA , África do Sul/epidemiologia
15.
Influenza Other Respir Viruses ; 11(2): 177-181, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27865064

RESUMO

Trivalent seasonal influenza vaccine effectiveness during the 2015 season in South Africa was assessed using a test-negative case control study design. Influenza A(H1N1)pdm09 was the dominant circulating strain. Overall influenza vaccine coverage was 3.2% (29/899). The vaccine effectiveness estimate, against any influenza virus infection, adjusted for age, underlying conditions and timing within season was 46.2% (95% CI: -23.5 to 76.5), and 53.6% (95% CI: -62.6 to 80.3) against influenza A(H1N1)pdm09.


Assuntos
Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Pacientes Ambulatoriais/estatística & dados numéricos , Potência de Vacina , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza B/imunologia , Vírus da Influenza B/isolamento & purificação , Influenza Humana/epidemiologia , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Estações do Ano , Vigilância de Evento Sentinela , África do Sul , Vacinação , Adulto Jovem
16.
BMC Infect Dis ; 16: 236, 2016 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-27246848

RESUMO

BACKGROUND: Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection in young children in both the community and hospital setting. METHODS: The clinical presentation, patient and phylogenetic characteristicsof laboratory-confirmed cases of RSV, as well as risk factors for nosocomial infectionat Red Cross War Memorial Children's Hospital in Cape Town were analysed. A multiplex PCR assay that detects 7 respiratory viruses was used to identify RSV nucleic acid on respiratory specimens. RESULTS: A total of 226 children were studied, ages ranging between 1 week and 92.5 months (median: 2.8 months, IQR: 1.3-6.3 months) and 51.8 % were males. The median duration of symptoms prior to diagnosis was 2 days (IQR: 1-4 days). Nosocomial infections wereidentified in 22 (9.7 %) children. There were pre-existing medical conditions in 113 (50.0 %) excluding HIV, most commonly prematurity (n = 58, 50.0 %) and congenital heart disease (n = 34, 29.3 %). The commonest presenting symptoms were cough (196, 86.7 %), difficulty in breathing (115, 50.9 %) and fever (91, 41.6 %).A case fatality rate of 0.9 % was recorded. RSV group A predominated (n = 181, 80.1 %) while group B accounted for only 45 (19.9 %) of the infections. The prevalent genotypes were NA1 (n = 127,70.1 %), ON1 (n = 45,24.9 %) and NA2 (n = 9,5.0 %) for group A while the only circulating RSV B genotype was BA4. There was no significant difference in the genotype distribution between the nosocomial and community-acquired RSV infections. Age ≥ 6 months was independently associated with nosocomial infection. CONCLUSIONS: A large percentage of children with RSV infection had pre-existing conditions. Approximately one tenth of the infections were nosocomial with age 6 months or older being a risk factor. Though both RSV groups co-circulated during the season, group A was predominant and included the novel ON1 genotype. Continued surveillance is necessary to identify prevalent and newly emerging genotypes ahead of vaccine development and efficacy studies.


Assuntos
Criança Hospitalizada , Infecções por Vírus Respiratório Sincicial/epidemiologia , Vírus Sincicial Respiratório Humano/isolamento & purificação , Criança , Criança Hospitalizada/estatística & dados numéricos , Pré-Escolar , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/virologia , Feminino , Genótipo , Hospitais Pediátricos , Humanos , Lactente , Recém-Nascido , Masculino , Filogenia , Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Humano/classificação , África do Sul/epidemiologia
17.
PLoS One ; 10(11): e0141744, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26565994

RESUMO

Traditional modes of investigating influenza nosocomial transmission have entailed a combination of confirmatory molecular diagnostic testing and epidemiological investigation. Common hospital-acquired infections like influenza require a discerning ability to distinguish between viral isolates to accurately identify patient transmission chains. We assessed whether influenza hemagglutinin sequence phylogenies can be used to enrich epidemiological data when investigating the extent of nosocomial transmission over a four-month period within a paediatric Hospital in Cape Town South Africa. Possible transmission chains/channels were initially determined through basic patient admission data combined with Maximum likelihood and time-scaled Bayesian phylogenetic analyses. These analyses suggested that most instances of potential hospital-acquired infections resulted from multiple introductions of Influenza A into the hospital, which included instances where virus hemagglutinin sequences were identical between different patients. Furthermore, a general inability to establish epidemiological transmission linkage of patients/viral isolates implied that identified isolates could have originated from asymptomatic hospital patients, visitors or hospital staff. In contrast, a traditional epidemiological investigation that used no viral phylogenetic analyses, based on patient co-admission into specific wards during a particular time-frame, suggested that multiple hospital acquired infection instances may have stemmed from a limited number of identifiable index viral isolates/patients. This traditional epidemiological analysis by itself could incorrectly suggest linkage between unrelated cases, underestimate the number of unique infections and may overlook the possible diffuse nature of hospital transmission, which was suggested by sequencing data to be caused by multiple unique introductions of influenza A isolates into individual hospital wards. We have demonstrated a functional role for viral sequence data in nosocomial transmission investigation through its ability to enrich traditional, non-molecular observational epidemiological investigation by teasing out possible transmission pathways and working toward more accurately enumerating the number of possible transmission events.


Assuntos
Infecção Hospitalar/transmissão , Infecção Hospitalar/virologia , Vírus da Influenza A Subtipo H1N1/genética , Influenza Humana/transmissão , Influenza Humana/virologia , Sequência de Bases , Teorema de Bayes , Criança , Infecção Hospitalar/epidemiologia , Hospitais Pediátricos , Humanos , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/epidemiologia , Dados de Sequência Molecular , Filogenia , África do Sul/epidemiologia
18.
J Infect ; 71(5): 578-86, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26366941

RESUMO

OBJECTIVES: The household is important in influenza transmission due to intensity of contact. Previous studies reported secondary attack rates (SAR) of 4-10% for laboratory-confirmed influenza in the household. Few have been conducted in middle-income countries. METHODS: We performed a case-ascertained household transmission study during May-October 2013. Index cases were patients with influenza-like-illness (cough and self-reported or measured fever (≥38 °C)) with onset in the last 3 days and no sick household contacts, at clinics in South Africa. Household contacts of index cases with laboratory-confirmed influenza were followed for 12 days. RESULTS: Thirty index cases in 30 households and 107/110 (97%) eligible household contacts were enrolled. Assuming those not enrolled were influenza negative, 21/110 household contacts had laboratory-confirmed influenza (SAR 19%); the mean serial interval was 2.1 days (SD = 0.35, range 2-3 days). Most (62/82; 76%) household contacts who completed the risk factor questionnaire never avoided contact and 43/82 (52%) continued to share a bed with the index case after illness onset. CONCLUSION: SAR for laboratory-confirmed influenza in South Africa was higher than previously reported SARs. Household contacts did not report changing behaviors to prevent transmission. These results can be used to understand and predict influenza transmission in similar middle-income settings.


Assuntos
Características da Família , Influenza Humana/transmissão , Influenza Humana/virologia , Adolescente , Adulto , Criança , Saúde da Família , Feminino , Seguimentos , Humanos , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H1N1/fisiologia , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/fisiologia , Influenza Humana/epidemiologia , Masculino , Fatores de Risco , Estações do Ano , África do Sul/epidemiologia , Inquéritos e Questionários , Adulto Jovem
20.
J Immunol Tech Infect Dis ; 2(1): 1000106, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-25333073

RESUMO

BACKGROUND: The epidemiology and impact of multiple concurrent Human papillomavirus (HPV) infections on the natural history of cervical disease is uncertain, but could have significant implications for cervical cancer prevention and HPV vaccination strategies. METHODS: A cross-sectional prevalence study was conducted to determine the overall prevalence of HPV and the rate of multiple concurrent HPV infections, in a cohort of sexually active HIV-uninfected South African adolescents. HPV genotyping was performed using the polymerase chain reaction. RESULTS: Overall prevalence of HPV was 64.1%. Multiple concurrent HPV infections were found in 43.6% of participants and 68% of HPV-infected participants. Non-vaccine high-risk HPV (HR-HPV) genotypes were found much more often than vaccine types (HPV16 and HPV18). CONCLUSIONS: Our cohort of young South African females was found to have a high overall prevalence of HPV and multiple concurrent HPV infections. Most HR-HPV infections found were genotypes other than HPV16 or HPV18.

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