miRNA Signatures in Sera of Patients with Active Pulmonary Tuberculosis.

Several studies showed that assessing levels of specific circulating microRNAs (miRNAs) is a non-invasive, rapid, and accurate method for diagnosing diseases or detecting alterations in physiological conditions. We aimed to identify a serum miRNA signature to be used for the diagnosis of tuberculosis (TB). To account for variations due to the genetic makeup, we enrolled adults from two study settings in Europe and Africa. The following categories of subjects were considered: healthy (H), active pulmonary TB (PTB), active pulmonary TB, HIV co-infected (PTB/HIV), latent TB infection (LTBI), other pulmonary infections (OPI), and active extra-pulmonary TB (EPTB). Sera from 10 subjects of the same category were pooled and, after total RNA extraction, screened for miRNA levels by TaqMan low-density arrays. After identification of "relevant miRNAs", we refined the serum miRNA signature discriminating between H and PTB on individual subjects. Signatures were analyzed for their diagnostic performances using a multivariate logistic model and a Relevance Vector Machine (RVM) model. A leave-one-out-cross-validation (LOOCV) approach was adopted for assessing how both models could perform in practice. The analysis on pooled specimens identified selected miRNAs as discriminatory for the categories analyzed. On individual serum samples, we showed that 15 miRNAs serve as signature for H and PTB categories with a diagnostic accuracy of 82% (CI 70.2-90.0), and 77% (CI 64.2-85.9) in a RVM and a logistic classification model, respectively. Considering the different ethnicity, by selecting the specific signature for the European group (10 miRNAs) the diagnostic accuracy increased up to 83% (CI 68.1-92.1), and 81% (65.0-90.3), respectively. The African-specific signature (12 miRNAs) increased the diagnostic accuracy up to 95% (CI 76.4-99.1), and 100% (83.9-100.0), respectively. Serum miRNA signatures represent an interesting source of biomarkers for TB disease with the potential to discriminate between PTB and LTBI, but also among the other categories

Systematic assessment of clinical and bacteriological markers for tuberculosis reveals discordance and inaccuracy of symptom-based diagnosis for treatment response monitoring

This work was supported by Commonwealth PhD studentship award to Dr Bariki Mtafya (Award number: TZS-2016-718) at University of St Andrews and European and Developing Countries Clinical Trials Partnership through TWENDE project (grant number; TWENDE-EDCTP-CSA-2014-283) and PanACEA II (grant number; 97118-PanACEA-TRIA.2015.1102) awarded to Professor Stephen Gillespie and Dr Wilber Sabiiti at the University of St Andrews, UK.Background : Clinical symptoms are the benchmark of tuberculosis (TB) diagnosis and monitoring of treatment response but is not clear how they relate to TB bacteriology, particularly the novel tuberculosis Molecular Bacterial Load Assay (TB-MBLA). Methods : Presumptive cases were bacteriologically confirmed for TB and assessed for symptom and bacteriological resolution using smear microscopy (SM), culture and TB-MBLA over 6-month treatment course. Kaplan Meier and Kappa statistics were used to test relationship between symptom- and bacteriological-positivity. Results : A cohort of 46 bacteriologically confirmed TB cases were analysed for treatment response over a six-month treatment course. Pre-treatment symptom and bacteriological positivity concurred in over 70% of the cases. This agreement was lost in over 50% of cases whose chest pain, night sweat, and loss of appetite had resolved by week 2 of treatment. Cough resolved at a 3.2% rate weekly and was 0.3% slower than the combined bacteriological (average of MGIT and TB-MBLA positivity) resolution rate, 3.5% per week. Drop in TB-MBLA positivity reflected fall in bacillary load, 5.7±1.3- at baseline to 0.30±1.0- log10 eCFU/mL at month 6, and closer to cough resolution than other bacteriological measures, accounting for the only one bacteriologically positive case out of seven still coughing at month 6. Low baseline bacillary load patients were more likely to be bacteriologically negative, HR 5.6, p=0.003 and, HR 3.2, p=0.014 by month-2 and 6 of treatment respectively. Conclusion : The probability of clinical symptoms reflecting bacteriological positivity weakens as patient progresses on anti-TB therapy, making symptom-based diagnosis a less reliable marker of treatment response.Publisher PDFPeer reviewe

High Seroprevalence for Typhus Group rickettsiae, southwestern Tanzania.

Rickettsioses caused by typhus group rickettsiae have been reported in various African regions. We conducted a cross-sectional survey of 1,227 participants from 9 different sites in the Mbeya region, Tanzania; overall seroprevalence of typhus group rickettsiae was 9.3%. Risk factors identified in multivariable analysis included low vegetation density and highway proximity

Model-based relationship between the molecular bacterial load assay and time-to-positivity in liquid culture

The molecular bacterial load (MBL) assay is a new tuberculosis biomarker which provides results in ∼4 hours. The relationship between MBL and time-to-positivity (TTP) has not been thoroughly studied and predictive models do not exist. We aimed to develop a model for MBL and identify the MBL-TTP relationship in patients. The model was developed on data from 105 tuberculosis patients from Malawi, Mozambique and Tanzania with joint MBL and TTP observations quantified from patient sputum collected for 12 weeks. MBL was quantified using polymerase chain reaction (PCR) of mycobacterial RNA and TTP using the Mycobacterial Growth Indicator Tube (MGIT) 960 system. Treatment consisted of isoniazid, pyrazinamide and ethambutol in standard doses together with rifampicin 10 or 35 mg/kg. The developed MBL-TTP model included several linked sub-models; a component describing decline of bacterial load in sputum, another component describing growth in liquid culture and a hazard model translating bacterial growth into a TTP signal. Additional components for contaminated and negative TTP samples were included. Visual predictive checks performed using the developed model gave good description of the observed data. The model predicted greater total sample loss for TTP than MBL due to contamination and negative samples. The model detected an increase in bacterial killing for 35 versus 10 mg/kg rifampicin (p=0.002). In conclusion, a combined model for MBL and TTP was developed that described the MBL-TTP relationship. The full MBL-TTP model or each sub-model used separately. Secondly, the model can be used to predict biomarker response for MBL given TTP data or vice versa in historical or future trials.PostprintPeer reviewe

Emerging viral infectious disease threat: Why Tanzania is not in a safe zone

Emerging diseases are global threat towards human existence. Every country is exposed to potentially emergence of infectious diseases. Several factor such as changes in ecology, climate and human demographics play different roles in a complex mechanism contributing to the occurrence of infectious diseases. Important aspects towards control in case of outbreaks are surveillance, preparedness and early response. Tanzania should therefore take opportunity of the calm situation currently present, to prepare. Except for HIV/AIDS, Tanzania has not experienced a major public health threat. However, the question is, is the country safe from emerging and re-emerging infectious diseases? In this article we try to explore the danger of emerging infectious disease (EID) epidemics in Tanzania and the risks attached if an outbreak is to occur. The aim is to formulate recommendations to the government, responsible authorities and general population of what can be done to improve the level of EID preparedness in the country. In conclusion, it is important to strengthen the capacity of community and healthcare staffs on how to respond to potential infectious disease outbreaks. Community-based surveillance systems should be incorporated into the national systems for early detection of public health events. It is also critical to enhance one health approach to increase cross-sectoral information sharing, surveillance and interventional strategies as regards to preparedness and response to disease outbreaks

Assessment of Knowledge, Attitude and Practices (KAP) on Hantavirus Infections at Community Level in Mbeya Region, Tanzania

This research article published by Longdom Publishing., Volume 7 • Issue 1, 2018Background: Hantaviruses are zoonotic RNA viral pathogens of public health concern in Tanzania and worldwide. These viruses circulate in both human and reservoir host in Tanzania, however, there is a gap in the assessment of knowledge, Attitude, and practices (KAP) which contributes to the transmission of the virus from Reservoir host to human being. This study aimed to assess the level of community knowledge, attitude, and practices that lead to the transmission of the virus from the reservoir host to a human being. Methods: Cross-sectional questionnaire survey was conducted in the four districts of Mbeya region between June 2018 to July 2018, where questionnaire data were obtained from 438 participants. Descriptive statistics and Chi-square (X2 ) test were used to explain the response of the participants. Results: (22/66) 33.3% and (22/372) 5.91% of both Health care workers and other members of the community, respectively had a knowledge about Hantavirus infections. (219/438) 50% of all participants have rodent breeding sites in their houses. However, (409/438) 93.4% of all participants did not wear masks when cleaning those breeding sites and this increases the risk for the transmission of Hantavirus infections. Discussion: Low level of knowledge for Hantavirus infections observed in the community increases the uncertainty of patient management as well as endangers the community health due to an increase of practices which increases the chance of pathogen transmission to a human being from the reservoir host. Conclusion: Updating the community about Hantavirus infection is more important as far as public health is concerned

Diagnostic accuracy of the Xpert ® MTB/RIF cycle threshold level to predict smear positivity: a meta-analysis

SETTING: Xpert® MTB/RIF is the most widely used molecular assay for rapid diagnosis of tuberculosis (TB). The number of polymerase chain reaction cycles after which detectable product is generated (cycle threshold value, CT) correlates with the bacillary burden.OBJECTIVE To investigate the association between Xpert CT values and smear status through a systematic review and individual-level data meta-analysis. DESIGN: Studies on the association between CT values and smear status were included in a descriptive systematic review. Authors of studies including smear, culture and Xpert results were asked for individual-level data, and receiver operating characteristic curves were calculated. RESULTS: Of 918 citations, 10 were included in the descriptive systematic review. Fifteen data sets from studies potentially relevant for individual-level data meta-analysis provided individual-level data (7511 samples from 4447 patients); 1212 patients had positive Xpert results for at least one respiratory sample (1859 samples overall). ROC analysis revealed an area under the curve (AUC) of 0.85 (95%CI 0.82-0.87). Cut-off CT values of 27.7 and 31.8 yielded sensitivities of 85% (95%CI 83-87) and 95% (95%CI 94-96) and specificities of 67% (95%CI 66-77) and 35% (95%CI 30-41) for smear-positive samples. CONCLUSION: Xpert CT values and smear status were strongly associated. However, diagnostic accuracy at set cut-off CT values of 27.7 or 31.8 would not replace smear microscopy. How CT values compare with smear microscopy in predicting infectiousness remains to be seen

Wuchereria bancrofti infection is linked to systemic activation of CD4 and CD8 T cells

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. Methodology/Principal findings Two-hundred and thirty-five HIV negative adults were tested using Trop Bio ELISA for detection of W. bancrofti infection and Kato Katz urine filtration and stool based RT-PCR for detection of soil transmitted helminths and schistosomiasis. FACS analysis of the fresh peripheral whole blood was used to measure T cell activation markers (HLA-DR, CD38), differentiation markers (CD45, CD27), markers for regulatory T cells (FoxP3, CD25) and the HIV entry receptor CCR5. Frequencies of activated HLA-DRpos CD4 T cells were significantly increased in subjects with W. bancrofti infection (n = 33 median: 10.71%) compared to subjects without any helminth infection (n = 42, median 6.97%, p = 0.011) or those with other helminths (Schistosoma haematobium, S. mansoni, Trichuris trichiura, Ascaris lumbricoides, hookworm) (n = 151, median 7.38%, p = 0.009). Similarly, a significant increase in HLA-DR(pos)CD38(pos) CD4 T cells and effector memory cells CD4 T cells (CD45RO(pos)CD27(neg)) was observed in filarial infected participants. Multivariable analyses further confirmed a link between W. bancrofti infection and systemic activation of CD4 T cells independent of age, fever, gender or other helminth infections. Conclusions/Significance W. bancrofti infection is linked to systemic CD4 T cell activation, which may contribute to the increased susceptibility of W. bancrofti infected individuals to HIV infection

Health-related quality of life and psychological distress among adults in Tanzania: a cross-sectional study

Little data is available on health-related quality of life (HRQoL) and mental health of the general population in Tanzania. We aimed to describe HRQoL and level of psychological distress among adults in Mbeya and Songwe Regions of Tanzania. Methods We conducted a cross-sectional study between April and October 2019 in Mbeya and Songwe Regions. Data were collected using the Medical Outcomes Short Form-36 (SF-36) questionnaire and the Page Kessler Psychological Distress Scale (K10). We described demographic characteristics of participants and used log-binomial regression to identify participant characteristics associated with psychological distress (K10 score ≥ 20). Results A total of 393 adults were enrolled. The participants had a median age of 29 years (IQR 23–40) and 54.2% were male. Participants reported a physical component summary score (PCS) with a mean of 54.7 (SD7.1) and a mental component summary score (MCS) with a mean of 55.5 (SD5.1). Older participants (≥ 40 year) and those that were divorced/widowed reported lower physical functioning, energy/vitality and emotional well-being compared to their counterparts ( p < 0.05). In terms of psychological distress, majority of participants (78.4%; 305/389) reported that they were likely to be well (K10 score < 20), while 13.4% (52/389) reported to have mild (K10 score 20–24), 5.7% (22/389) moderate (K10 score 25–29), and 2.6% (10/389) severe (K10 score ≥ 30) psychological distress. Conclusions Physical function and mental well-being in this adult population from Tanzania were lower than that reported in other similar research in Tanzania and other African countries. This study provides valuable references for other research initiatives and clinical services in this region

Increased and Expedited Case Detection by Xpert MTB/RIF Assay in Childhood Tuberculosis: A Prospective Cohort Study

The Xpert MTB/RIF assay is a quick and accurate tuberculosis diagnostic tool in children. Compared with microscopy, 3-fold more tuberculosis cases were detected with a similar turnaround time, resulting in a potentially shortened time to tuberculosis diagnosi