Water-borne transmission of Cryptosporidium and Giardia in Belgium and Bangladesh

Currently more than one billion people worldwide do not have access to safe drinking water or adequate sanitation. Important water-borne diarrhoeal diseases include cryptosporidiosis and giardiosis. Both in developed and developing countries, Cryptosporidium and Giardia are important causes of diarrhoea. This thesis aimed at studying (water-borne) transmission of Cryptosporidium and Giardia in Belgium and in Bangladesh. The literature review (chapter 1) starts with introducing Cryptosporidium and Giardia, followed by an overview of their prevalence and clinical importance in both human and animals. Then the different transmission cycles of both parasites are discussed, including water-borne transmission through drinking water and recreational water. Finally, different methods for detecting and quantifying Cryptosporidium and Giardia in water are described. In chapter 2, we monitored the presence of Cryptosporidium and Giardia in four drinking water catchment sites in Belgium. An attempt was made to determine the origin of (oo)cysts applying molecular tools. No contamination was found in purified drinking water at any site. In three catchments (Zillebeke, Gavers and Dikkebus), only low numbers of (oo)cysts were recovered from raw water samples. However, raw water samples from the Blankaart catchment site were frequently contaminated with Cryptosporidium and Giardia, especially in winter and spring. C. andersoni, C. suis, C. horse genotype, C. parvum and C. hominis and Giardia duodenalis assemblage AI, AII, BIV, BIV-like and E were identified. The genotyping results suggest that agriculture may be a more important source of surface water contamination than human waste in this catchment. Continuous monitoring of treated water for the presence of Cryptosporidium and Giardia would be justified and (point) sources of surface water contamination should be identified. In chapter 3, the infection risk of Cryptosporidium and Giardia in recreational waters in Belgium was assessed in swimming pools, recreational lakes, splash parks and water fountains. The risk of Giardia infection in the swimming pools varied from 1.13x10-6 to 2.49x10-6 per swim per person. In recreational lakes the estimated infection risk varied from 2.79x10-5 to 5.74x10-5 per swim per person for Cryptosporidium and from 7.04x10-5 to 1.46 x10-4 for Giardia and for other outdoor water recreation activities the estimated infection risk was 5.71x10-6 for Cryptosporidium and 1.47x10-5 for Giardia. However, given that mainly animal-associated species/genotypes were identified and that the (oo)cyst viability was not assessed, the infection risk associated with recreational lakes may be overestimated. No Cryptosporidium was found in splash parks and water fountains, but the presence of Giardia cysts suggests a risk for human infection. In chapter 4, we assessed the zoonotic and water-borne transmission of Cryptosporidium and Giardia in rural Bangladesh. High prevalences of Cryptosporidium and Giardia were found in both calves and their handlers, but genotyping results indicated that there was no zoonotic transmission between these two host populations. During monthly sampling of two village water ponds for two years, Cryptosporidium and Giardia were detected in 14/24 and 12/24 water samples respectively. Although the presence of Cryptosporidium and Giardia in both water ponds suggests that water-borne transmission of Cryptosporidium and Giardia is possible, genotyping results from infected village inhabitants and their cattle suggested no significant direct or indirect (water-borne) transmission of Giardia between cattle and people in this area of rural Bangladesh. In chapter 5, we provided recommendations for water companies and outlined future studies on water-borne transmission both in Belgium and in Bangladesh

Enabling Technologies for 3D ICs: TSV Modeling and Analysis

Through silicon via (TSV) based three-dimensional (3D) integrated circuit (IC) aims to stack and interconnect dies or wafers vertically. This emerging technology offers a promising near-term solution for further miniaturization and the performance improvement of electronic systems and follows a more than Moore strategy. Along with the need for low-cost and high-yield process technology, the successful application of TSV technology requires further optimization of the TSV electrical modeling and design. In the millimeter wave (mmW) frequency range, the root mean square (rms) height of the TSV sidewall roughness is comparable to the skin depth and hence becomes a critical factor for TSV modeling and analysis. The impact of TSV sidewall roughness on electrical performance, such as the loss and impedance alteration in the mmW frequency range, is examined and analyzed following the second order small perturbation method. Then, an accurate and efficient electrical model for TSVs has been proposed considering the TSV sidewall roughness effect, the skin effect, and the metal oxide semiconductor (MOS) effect. However, the emerging application of 3D integration involves an advanced bio-inspired computing system which is currently experiencing an explosion of interest. In neuromorphic computing, the high density membrane capacitor plays a key role in the synaptic signaling process, especially in a spike firing analog implementation of neurons. We proposed a novel 3D neuromorphic design architecture in which the redundant and dummy TSVs are reconfigured as membrane capacitors. This modification has been achieved by taking advantage of the metal insulator semiconductor (MIS) structure along the sidewall, strategically engineering the fixed oxide charges in depletion region surrounding the TSVs, and the addition of oxide layer around the bump without changing any process technology. Without increasing the circuit area, these reconfiguration of TSVs can result in substantial power consumption reduction and a significant boost to chip performance and efficiency. Also, depending on the availability of the TSVs, we proposed a novel CAD framework for TSV assignments based on the force-directed optimization and linear perturbation

Recent advances on palm oil mill effluent (POME) pretreatment and anaerobic reactor for sustainable biogas production

Palm oil is one of the leading agricultural crops in the world, as it dominates 34% of the global vegetable oil market, with approximately 64.6*103 million kgs of production in 2017. However, along with its breakthrough, the generation of palm oil mill effluent (POME) as uncontrolled waste has become a serious matter and requires proper management to reduce its negative effects on the environment. Subsequently, the high organic content of POME makes it possible to convert waste into value-added products, such as biogas. A ratio of 0.5 for biological oxygen demand to chemical oxygen demand (BOD/COD) indicates a high possibility for biological treatment. Recently, the utilisation of POME as a cheap source for biogas production has gained an extraordinary amount of attention, and intensive research has been conducted on the upstream to downstream process. Finding the most suitable and efficient pretreatment technique and reactor configuration are vital parameters for the treatment and conversion of POME to biogas. This review describes existing pretreatment processes for POME and recommends recently manufactured high-rate anaerobic reactors as the most suitable and efficient pretreatment technique for maximising the extraction of biogas from POME

Occurrence and potential health risk of Cryptosporidium and Giardia in different water catchments in Belgium

Human wastewater and livestock can contribute to contamination of surface water with Cryptosporidium and Giardia. In countries where a substantial proportion of drinking water is produced from surface water, e.g., Belgium, this poses a constant threat on drinking water safety. Our objective was to monitor the presence of Cryptosporidium and Giardia in different water catchment sites in Belgium and to discriminate between (oo) cysts from human or animal origin using genotyping. Monthly samples were collected from raw water and purified drinking water at four catchment sites. Cryptosporidium and Giardia were detected using USEPA method 1623 and positive samples were genotyped. No contamination was found in purified water at any site. In three catchments, only low numbers of (oo) cysts were recovered from raw water samples (<1/liter), but raw water samples from one catchment site were frequently contaminated with Giardia (92 %) and Cryptosporidium (96 %), especially in winter and spring. Genotyping of Giardia in 38 water samples identified the presence of Giardia duodenalis assemblage AI, AII, BIV, BIV-like, and E. Cryptosporidium andersoni, Cryptosporidium suis, Cryptosporidium horse genotype, Cryptosporidium parvum, and Cryptosporidium hominis were detected. The genotyping results suggest that agriculture may be a more important source of surface water contamination than human waste in this catchment. In catchment sites with contaminated surface water, such as the Blankaart, continuous monitoring of treated water for the presence of Cryptosporidium and Giardia would be justified and (point) sources of surface water contamination should be identified

Transmission and pathology of Streptococcus inane in monosex Nile tilapia (Oreochromis niloticus) in aquaculture of Bangladesh

Streptococcus iniae is a major fish pathogen, recently emergent outbreaks were recorded in commercially cultured monosex Nile tilapia (Oreochromis niloticus) result in significant losses termed “streptococcosis”-causes unusual appearances with multi-focal pin-point haemorrhages, abscesses, necrosis and ascites in skin, fin, muscle, liver, spleen, kidney, blood, interstitial fluid specially in central nervous system and brain. This disease was more prevalent (&gt;26%) at summer when the water temperature was approximately &gt;25oC, percentage of mortality was higher &gt;41% during the overcrowding and improper water chemistry. Raised levels of glucose and ammonium in blood serum causes reduced number of free blood cells released into the haemolymph to stomach and gut, result in refrain from eating in diseased tilapia. Stocking density (200 fish/decimal; class IV) had significant effect (P&lt;0.01) on the total production (5,000 to 5,500 kg/ha). S. iniae in the circulating blood cells, extra-tubular haemal spaces containing blood vessels, fixed phagocytes in the hepatopancreas (gastrointestinal tract), bacteria-like particles in the brain tissue, vacuum and necrosis in hepatocytes revealed with histopathology. In vitro study revealed that cohabitation of dead or infected fish with healthy fish resulted infection (horizontal transmission mechanism) to the healthy fish

Neonatal Tetanus, Yet Not Gone: Infectious Disease Hospital Experience

Background: Although neonatal tetanus (NT) has been declared eliminated from Bangladesh in June 2008, it is not uncommon in Infectious Disease Hospital (IDH) in Dhaka. There are various presentations of NT cases and treatment practices also vary. Objective: This study was conducted to describe our experiences with NT at IDH outlining the clinical characteristics, maternal immunization and treatment outcome. Materials and Methods: Thirty neonates admitted with tetanus in IDH from March 2011 to December 2012 were observed prospectively to study risk factors, clinical features and outcomes during hospital stay. Results: Among 30 neonates with tetanus 80% were male. Eighty seven percent of these cases were delivered at home and 83% of mothers did not receive any dose of tetanus toxoid (TT). Fifty percent of the neonates were admitted within 3–5 days of age. Shidur (Vermillion) was applied to the cord stump in 23% neonates. Hot soak was applied to the umbilicus in 5 (17%) neonates. Presenting features were convulsion and/or stiffness or rigidity (93%), inability to suck (90%) and umbilical infection (70%). During hospital care multiple cardiac arrests developed in 86% neonates and apnea developed in 60% of the neonates. Treatment was given in pediatric ward. Case fatality rate was 50%. Conclusion: Risk factors observed in NT cases were maternal non-immunization, unhygienic delivery practices and application of substances in the umbilicus. Antenatal TT administration and universal immunization under school health program should be more emphasized to prevent NT