Tuberculosis in Children: Diagnosis and Epidemiology

Globally, an estimated one-million new tuberculosis (TB) cases occurred in children in 2014. For a long time, research of TB in children has been neglected. Most research and surveillance of TB is performed in adults, and the resulting lack of evidence in children is a major barrier for implementation of rational control strategies for children, including diagnosis. More research on TB in children is of importance as children are more susceptible to developing severe extrapulmonary TB, children require different approaches to both diagnosis and treatment and paediatric TB reflects the ongoing transmission of TB in the population. This research gap on the epidemiology of tuberculosis in children, especially in high burden countries, should be addressed in order to better understand the dynamics of TB transmission in both adults and children. Accurate data are the basis for establishment of effective control strategies. This thesis aims to assess the diagnostic role of microscopic observation drug susceptibility (MODS) and mycobacterial blood culture for diagnosis of TB in children as well as to present the epidemiological characteristics of paediatric TB in northern Vietnam with regard to drug resistance and genotypes of Mycobacterium tuberculosis (MTB), the causative agent of TB, isolated from them. MODS is a low cost non-commercial liquid culture assay to detect MTB by microscopy. MODS was compared with conventional assays including Ziehl-Neelsen smear (ZN) and Löwenstein-Jensen culture (LJ) in a study conducted from 2009 to 2010 at the National Hospital for Paediatrics, a general paediatric hospital, in Hanoi, Vietnam. In suspected paediatric TB cases, the MODS test was shown to be significantly more sensitive than both smear (46.0% vs. 8.8%) and LJ (46.0% vs. 38.9%), and significantly faster than LJ with a median time difference of 28 days in favour of MODS (7 days vs. 35 days). The findings suggest that MODS is a rapid low-cost diagnostic tool for TB diagnosis in the paediatric population. The additional yield of mycobacterial blood culture was assessed in comparison to routine detection methods for TB diagnosis in children in two hospitals in Vietnam. The findings show that mycobacterial blood culture detected an additional six TB cases of which 5 cases were negative with other tests and in the remaining case no other tests were done. All six cases were susceptible to rifampicin and isoniazid. The overall performance of TB blood culture was poor as compared to routine culture with regard to detection rate (2.9%, 16/554 vs. 16.6%, 92/554) and turnaround time (26 days vs. 14 days). The incremental cost for adding one additional TB case is substantial. Therefore, addition of mycobacterial blood culture into routine diagnostics has limited utility in resource limited settings. To assess the molecular epidemiology of paediatric TB in northern Vietnam, a collection of 125 MTB isolates from children with TB admitted to NHP during 2009 to 2013 was analysed. Drug susceptibility testing results from 121 isolates and genotypes from 120 isolates were generated. The phenotypic drug susceptibility testing showed that 20.7% was resistant to isoniazid (25/121), 3.3% resistant to rifampicin (4/121), 28.1% resistant to streptomycin (34/121) and 2.5% resistant to ethambutol (1/121). There were 4 cases with multidrug resistant TB. The high frequency of resistance to isoniazid and streptomycin are consistent with data from adults in Vietnam, suggesting the ongoing transmission of drug resistant MTB in the community. MIRU typing patterns showed that the Beijing genotype was predominant in this population (63.3%, 76/120), which is in agreement with various prior studies in adults in Vietnam. These findings provide more evidence to support the hypothesis of the epidemic spread of the Beijing genotype in Vietnam. In this study, an association between Beijing genotype and drug resistance to streptomycin and isoniazid was observed. The number of MDR isolates was too small to draw conclusions regarding association of MDR and Beijing genotype. Collectively, these results demonstrate that liquid culture can improve the yield of TB diagnosis in Vietnam and mycobacterial blood culture should not be routinely performed for paediatric cases. The molecular epidemiology study also showed that the Beijing genotype is the predominant lineage among actively transmitted strains in Vietnam and that it is associated with both isoniazid and streptomycin resistance. Paediatric TB remains a significant cause of morbidity and mortality in Vietnamese children and sustained political and social commitment from all stakeholders, including governments, funders, academics and the medical community will be needed to improve diagnosis, treatment and prevention of TB in children globally

The influence of the Generation Z's perception and psychological ownership on repurchase intention of e-shopping: Evidence from Vietnam

One of the most significant achievements of Information Communication Technology (ICT) in commerce is e-shopping, which changes shopping behavior in the retail sector. This research examines how Generation Z's perceptions of e-shopping benefits and drawbacks and A qualitative method through in-depth interviews and a quantitative method via a questionnaire survey is employed to assess the Generation Z-ers' attitudes, perceptions, and psychology toward the benefits and drawbacks of e-shopping and their intention of choosing this channel for repurchasing. PLS-SEM will be associated to discover the relationships between Generation Z-ers' psychological ownership, perceptions of e-shopping benefits and drawbacks, and their online repurchase intention. Findings suggest that Generation Z-ers' online repurchase intention is due to perceived benefits, psychological ownership, and is regardless of perceived drawbacks. Furthermore, as a moderator of the effect of perceived drawbacks on repurchase intention, psychological ownership may lessen the Generation Z-ers' concerns of e-shopping drawbacks and enhance their online repurchase intention.Internal Grant Agency of FaME TBU in Zlin [IGA/FaME/2020/011

Risk-based approach to food safety research: Application to pork value chains in Vietnam

Introduction: Food-borne disease is a major public health issue in Vietnam. The contamination of popular foods can occur all along the food value chains. It is important to understand how and where food safety issues arise in order to mitigate and prevent food-borne diseases. Risk-based approach is a tool for managing food safety, however in Vietnam it is rarely applied and the capacity for application is still lacking. This paper describes how food safety risk assessment research has been applied for the pork value chain in Vietnam. Methods: We have conducted a risk assessment research to assess health risks related to pork consumption in the context of pig smallholder value chains and pork traded in informal markets. We collected 216 samples from 72 pig farms (floor swab, drinking and waste water), 545 samples from 49 slaughterhouses (carcass swab, lymph node, rectal feces, floor swab and washing water) and 514 samples from 220 pork retailed shops at informal markets (pork cuts, ground pork and cutting board swab) in Hung Yen and Nghe An provinces in the north and central of Vietnam. These 1275 samples were analyzed to detect qualitatively and quantitatively for Salmonella and E. coli. Chemical hazards (antibiotic, growth promoters, and heavy metal residues) in 190 pork samples from informal markets were also analyzed. Pork consumption behavior and cross-contamination modalities during pork preparation were assessed. Findings and interpretations: Overall prevalence of Salmonella combined from all types of above mentioned samples at pig farms, slaughterhouses and pork shops were 35%, 30% and 37%, respectively. Salmonella contamination in the final product (pork at market) was 45% and an average concentration of 9 MPN/g was recorded. E. coli average loads along different points of the chain were 5.3±1.4 (farm floor swabs), 2.9±0.9 (carcass swabs), 3.1±1.0 (slaughterhouse floor swabs), and 3.3±1.1 (market shop cutting board swabs) logCFU/cm2 , whereas pork from market had 3.4±0.9 logCFU/g. Demonstrated high levels of Salmonella in the final product (pork at market) induces the potential health risks for the consumers. High values for E. coli indicates general poor hygiene along the chain. 50% and 16.7% pooled samples were positive with sulfamethazine and chloramphenicol, with average residue levels of 156 µg/kg and 0.54 µg/kg, respectively. A quantitative risk model is being developed and integrates information on contamination along the pork value chain to characterize the health risk caused by Salmonella. Appropriate hygiene practices and management are required to achieve better pork quality and reduce the risk for the consumers

NĂNG SUẤT SƠ CẤP Ở ĐẦM THỊ NẠI, TỈNH BÌNH ĐỊNH

Experiments of photosynthesis assessment of phytoplankton and seaweed had been carried out in Thi Nai lagoon in rainy season (October, 2013) and dry season (May, 2014). The results showed that primary productivity of phytoplankton was 8 - 149 mgC/m3/day, and that productivity of seaweed Gracilaria verrucosa was 0.139 - 0.197 mg C/g seaweed/day. During photosynthesis process of phytoplankton, an amount of 1.42 - 1.6 tons mineral nitrogen/day and 0.14 - 0.17 tons phosphate/day was consumed in the whole lagoon. The photosynthesis process of seaweed also consumed an amount of 0.74 - 0.83 tons/day of inorganic nitrogen (including nitrate, nitrite, and ammonium), and 0.041 - 0.045 tons/day of phosphate in the whole lagoon.Các thí nghiệm đánh giá khả năng quang hợp của thực vật nổi và rong biển đã được thực hiện tại đầm Thị Nại (Bình Định) vào mùa mưa (tháng 10/2013) và mùa khô (tháng 5/2014). Kết quả nghiên cứu cho thấy năng suất sơ cấp của thực vật nổi và rong câu chỉ vàng Gracilaria verrucosa nằm trong khoảng 8 - 149 mgC/m3/ngày và khoảng 0,135 - 0,197 mgC/g rong/ngày. Trong quá trình quang hợp, thực vật nổi làm tiêu hao khoảng 1,42 - 1,6 tấn khoáng nitơ/ngày và 0,14 - 0,17 tấn phôtphat/ngày. Tương tự, quần xã rong trong đầm cũng làm tiêu hao khoảng 0,74 - 0,83 tấn/ngày các dinh dưỡng nitơ vô cơ và 0,041 - 0,045 tấn phôtphat/ngày trên toàn đầm Thị Nại

Hygiene and microbial contamination along the pork value chain in Vietnam

In Vietnam, pork accounts for 75% of total meat consumed daily at households. However, pork may contain high levels of microbial contamination such as Salmonella and Escherichia coli which might cause harm to consumers. To determine microbial contamination along the pork value chain, we collected 216 samples from 72 pig farms (floor swab, drinking and waste water), 545 from 49 slaughterhouses (carcass swab, lymph node, rectal feces, floor swab and washing water) and 514 from 220 pork shops in the informal markets (pork cuts, ground pork and cutting board swab) in two provinces of Vietnam (Hung Yen and Nghe An). Samples were analyzed to detect qualitatively and quantitatively Salmonella and E. coli. Overall prevalence of Salmonella combined from all types of above mentioned samples at pig farms, slaughterhouses and pork shops were 35%, 30% and 37%, respectively. Salmonella contamination in the final product (pork at market) was 45% and an average concentration of 9 MPN/g was recorded. E. coli average load along different points of the chain was 5.3 ± 1.4 (farm floor swabs), 2.9 ± 0.9 (carcass swabs), 3.1 ± 1.0 (slaughterhouse floor swabs), and 3.3 ± 1.1 (market shop cutting board swabs) logCFU/cm2, whereas pork from the market had 3.4 ± 0.9 logCFU/g. Demonstrated high levels of Salmonella in the final product (pork at market) induces the potential health risks for the consumers. High values for E. coli indicates general poor hygiene along the chain. Appropriate hygiene practices and management are required to achieve better pork quality and reduce the risk for the consumer. These data will serve as inputs for health risk assessments related to pork consumption