Publications by authors named "Clowes P"

There is an increased risk for tuberculosis (TB) infection and disease progression in prison settings. TB prevalence in prisons in low- and middle-income countries have been measured to be up to 50 -times higher than in the general population. The aim of the study was to perform active TB screening and estimate the burden of TB in central prisons in Tanzania mainland.

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Article Synopsis
  • The study explored the link between a specific parasitic infection and increased HIV susceptibility, previously noting a significant rise in HIV incidence among those infected.
  • Researchers analyzed blood samples from 350 HIV-negative individuals who tested positive for the parasitic infection, focusing on the presence of microfilariae (MF).
  • Results showed that individuals with MF had a higher rate of new HIV infections (7.8 cases per 100 person-years) compared to those without MF (1.8 cases per 100 person-years), highlighting a stronger association between MF and HIV susceptibility than initially thought.
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Background: Lymphatic filariasis is a mosquito transmitted parasitic infection in tropical regions. Annual mass treatment with ivermectin and albendazole is used for transmission control of Wuchereria bancrofti, the infective agent of lymphatic filariasis in many African countries, including Tanzania.

Methodology: In a general population study in Southwest Tanzania, individuals were tested for circulating filarial antigen, an indicator of W.

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Introduction: sub-Saharan Africa bears a high prevalence for hepatitis B virus (HBV) infection. This analysis aims at elucidating the exposure to HBV across different age groups in Mbeya Region in Tanzania and determines prevalences of hepatitis C (HCV) and hepatitis delta antigen (HDV) infections.

Methods: plasma samples from children and adults with defined HIV status were analysed for HBV, HCV and HDV markers.

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Schistosomiasis is a leading cause of morbidity in Africa. Understanding the disease ecology and environmental factors that influence its distribution is important to guide control efforts. Geographic information systems have increasingly been used in the field of schistosomiasis environmental epidemiology.

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Background: Susceptibility to HIV has been linked to systemic CD4+ T cell activation in cohorts of seronegative individuals with high HIV-exposure risk. We recently described an increased risk of HIV transmission in individuals infected with Wuchereria bancrofti, the causative agent for lymphatic filariasis, in a prospective cohort study. However, the reason for this phenomenon needs further investigation.

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Background: Rapid on-site diagnosis facilitates tuberculosis control. Performing Xpert MTB/RIF (Xpert) at point of care is feasible, even when performed by minimally trained health-care workers, and when compared with point-of-care smear microscopy, reduces time to diagnosis and pretreatment loss to follow-up. However, whether Xpert is cost-effective at point of care remains unclear.

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Background: Xpert MTB/RIF, the most widely used automated nucleic acid amplification test for tuberculosis, is available in more than 130 countries. Although diagnostic accuracy is well documented, anticipated improvements in patient outcomes have not been clearly identified. We performed an individual patient data meta-analysis to examine improvements in patient outcomes associated with Xpert MTB/RIF.

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Objectives: We evaluated the diagnostic performance of the novel next-generation Xpert MTB/RIF Ultra (Xpert Ultra) in comparison to Xpert MTB/RIF (Xpert) assay for the detection of paediatric pulmonary tuberculosis in high burden settings.

Methods: From May 2011 to September 2012, children with suspected pulmonary tuberculosis were enrolled at two Tanzanian sites and sputum samples were examined using sputum smear, Xpert and culture. Xpert Ultra was tested between January and June 2017 using sputum pellets, which had been stored at -80°C.

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Background: A marked decline in malaria morbidity and mortality has been reported after the introduction of artemisinin-based combination therapy (ACT) in high malaria prevalence countries in Africa. Data on the impact of ACT and on the prevalence of malaria has so far been scarce for Southwest Tanzania.

Methods: Between 2005 and 2011, a large general population cohort in the Mbeya Region in the south-west of Tanzania has been surveyed within the EMINI-study (Evaluation and Monitoring of the Impact of New Interventions).

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Objective: Linkage to care is the bridge between HIV testing and HIV treatment, care and support. In Tanzania, mobile testing aims to address historically low testing rates. Linkage to care was reported at 14% in 2009 and 28% in 2014.

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Background: The intestinal nematode Trichuris trichiura is among the most common causes of human infectious disease worldwide. As for other soil-transmitted nematodes, its reproductive success and thus prevalence and intensity of infection in a given area strongly depend on environmental conditions. Characterization of the influence of environmental factors can therefore aid to identify infection hot spots for targeted mass treatment.

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Background: As access to Xpert expands in high TB-burden settings, its performance against clinically diagnosed TB as a reference standard provides important insight as the majority of childhood TB is bacteriologically unconfirmed. We aim to describe the characteristics and outcomes of children with presumptive TB and TB disease, and assess performance of Xpert under programmatic conditions against a clinical diagnosis of TB as a reference standard.

Methods: Retrospective review of children evaluated for presumptive TB in Mbeya, Tanzania.

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Elastography, the imaging of elastic properties of soft tissues, is well developed for macroscopic clinical imaging of soft tissues and can provide useful information about various pathological processes which is complementary to that provided by the original modality. Scaling down of this technique should ply the field of cellular biology with valuable information with regard to elastic properties of cells and their environment. This paper evaluates the potential to develop such a tool by modifying a commercial optical coherence tomography (OCT) device to measure the speed of shear waves propagating in a three-dimensional (3D) medium.

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Background: The past decades have seen an ongoing controversial debate about whether the immune activation induced by helminths has an effect on the susceptibility of individuals to HIV. In view of this, we assessed the effect of lymphatic filariasis, a chronic helminth disease elicited by Wuchereria bancrofti, on HIV incidence in southwest Tanzania.

Methods: In this population-based cohort study, we enrolled a geographically stratified randomly chosen sample of about 10% of the households in nine distinct sites in southwest Tanzania.

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Background: The presence of IgG and IgM against Tat, an HIV protein important for viral replication and immune dysfunction, is associated with slow disease progression in clade B HIV-infected individuals. However, although Tat activities strictly depend on the viral clade, our knowledge about the importance of anti-Tat antibodies in non-clade B HIV infection is poor. The objective of this study was to investigate the association of different anti-Tat antibody isotypes with disease progression in non-clade B HIV-infected subjects and to study the relationship between anti-Tat humoral responses and immunological abnormalities.

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Unlabelled: Interleukin 2 (IL-2) signaling through the IL-2 receptor alpha chain (CD25) facilitates HIV replication in vitro and facilitates homeostatic proliferation of CD25(+) FoxP3(+) CD4(+) T cells. CD25(+) FoxP3(+) CD4(+) T cells may therefore constitute a suitable subset for HIV infection and plasma virion production. CD25(+) FoxP3(+) CD4(+) T cell frequencies, absolute numbers, and the expression of CCR5 and cell cycle marker Ki67 were studied in peripheral blood from HIV(+) and HIV(-) study volunteers.

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Background: Annual mass treatment with ivermectin and albendazole is used to treat lymphatic filariasis in many African countries, including Tanzania. In areas where both diseases occur, it is unclear whether HIV co-infection reduces treatment success.

Methodology: In a general population study in Southwest Tanzania, individuals were tested for HIV and circulating filarial antigen, an indicator of Wuchereria bancrofti adult worm burden, before the first and after 2 consecutive rounds of anti-filarial mass drug administration.

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Background: HIV-associated tuberculosis is difficult to diagnose and results in high mortality. Frequent extra-pulmonary presentation, inability to obtain sputum, and paucibacillary samples limits the usefulness of nucleic-acid amplification tests and smear microscopy. We therefore assessed a urine-based, lateral flow, point-of-care, lipoarabinomannan assay (LAM) and the effect of a LAM-guided anti-tuberculosis treatment initiation strategy on mortality.

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Background: The diagnosis of paediatric tuberculosis (TB) remains difficult in resource-: poor settings.

Objective: To evaluate induced sputum collection and examination using microscopy, culture and Xpert(®) MTB/RIF assay for the diagnosis of pulmonary TB (PTB) in a Tanzanian hospital vs. PTB diagnosis using clinical scoring tools alone.

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Setting: Tanzania is a high-burden country for tuberculosis (TB), and prisoners are a high-risk group that should be screened actively, as recommended by the World Health Organization. Screening algorithms, starting with chest X-rays (CXRs), can detect asymptomatic cases, but depend on experienced readers, who are scarce in the penitentiary setting. Recent studies with patients seeking health care for TB-related symptoms showed good diagnostic performance of the computer software CAD4TB.

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Background: The commercially available urine LAM strip test, a point-of-care tuberculosis (TB) assay, requires evaluation in a primary care setting where it is most needed. There is currently inadequate data to guide implementation in TB and HIV-endemic settings.

Methods: Adult HIV-infected outpatients with suspected pulmonary TB able to self-expectorate sputum from four primary clinics in South Africa, Zambia and Tanzania underwent diagnostic evaluation [sputum smear microscopy, Xpert-MTB/RIF, and culture (reference standard)] as part of a prospective parent study.

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Background: The successful cure of tuberculosis (TB) is dependent on adherence to treatment. Various factors influence adherence, however, few are easily modifiable. There are limited data regarding correlates of psychological distress and their association with non-adherence to anti-TB treatment.

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We evaluated the diagnostic performance of two tests based on the release of lipoarabinomannan (LAM) into the urine, the MTB-LAM-ELISA assay and the Determine TB-LAM-strip assay, in children with suspected tuberculosis (TB) in a high TB/HIV-prevalence setting.In a prospective study, 132 children with suspected active TB were assigned to diagnostic subgroups. Urine samples were subjected to testing by both assays to ascertain sensitivity and specificity.

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