Theses and dissertations (Health Sciences)

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Comparative nuclear magnetic resonance study of Natrum muriaticum LM1 produced in-house and obtained from commercial sources respectively
(2017) Miller, Garth Meredith; Botha, Izel; Ross, Ashley Hilton Adrian
Introduction Hahnemann was adamant that his methodology for LM1 prescription be reproduced exactly, in order to develop the latent medicinal properties of the crude substance reliably (Barthel 1991). Yet quality assurance practices during manufacturing are currently aligned to Good Manufacturing Process, in adherence to Pharmacopeia which permit substantial deviation from the strict quantities and practices (Kayne 2006) prescribed in Hahnemann’s 6th edition Organon (Hahnemann and O'Reilly 2001). Often the equipment, methods and practices favour expedience or utilise new technologies, under an assumption that the remedy produced is unaffected, since the mechanisms underlying the action of homoeopathic remedies are not understood or determined (Barthel 1991). Aim The primary purpose of this study was to compare and evaluate the nuclear magnetic resonance (NMR) spectra of Natrum muriaticum LM1, produced using strict adherence to original Hahnemannian methodology, to samples sourced from a representative variety of sources available to local homoeopathic practitioners, in the medicinal prescription form patients may receive. Additionally, the researcher set out to confirm that these Natrum muriaticum LM1 samples could be shown to produce distinct NMR spectra when compared to a Lactose LM1 control. The final objective was to ascertain whether two samples produced with the same strict adherence to Hahnemannian methodology, from same source materials would yield similar NMR Spectra, distinct from a Lactose LM1 control sample. Methodology The researcher produced an in-house Natrum muriaticum LM1 (0/1) sample in accordance with aphorism 272 of the 6th edition Organon (Hahnemann and O'Reilly 2001). Similarly, a second sample was produced by the DUT Homoeopharmaceutics Senior Lecturer, within the same ambient conditions and protocol. A third sample was produced by a local make-to-order (MTO) company, using the same sodium chloride crude substance sample utilised in the production of the first two samples. These three samples emulate the make-to-order (MTO) options available to homoeopathic practitioners. A fourth sample was obtained ex-stock from highly regarded local supplier (Homoeopathix Trading Company (South Africa)), while the fifth and sixth samples were procured ex-stock from highly regarded suppliers abroad, Helios (United Kingdom) and Roy & Co. (India) respectively. These samples represented the make-to-stock (MTS) sourcing options available to homoeopathic community. The researcher transported the samples to Chemistry Department of the University of Stellenbosch Chemistry Department in Cape Town. Any external influences such as vibration, changes in temperature, electromagnetic disturbances, heat or strong light were avoided or minimised as far as was practical. The six LM1 potency samples were prepared immediately prior to NMR analysis from their respective source materials to a 20% alcohol concentration, as could be done in practice for the patient prescription where the alcohol content would serve as a preservative. Four controls comprised the seventh, eighth, ninth and tenth samples, for comparative analysis and to confirm sample homogeneity. . Lactose (LM1) . Source lactose in solution . Water used in preparation of NMR samples . Ethanol solvent The ten samples were assigned a random reference number by Dr Jaco Brand (Nuclear Magnetic Resonance Unit Manager), to remove bias during NMR analysis. Five samples were drawn from each of the ten randomised samples and labelled, while deuterated dimethyl sulfoxide-d6 (DSMO) contained within a separate capillary tube served as an external lock and reference solvent. The researcher then carried out the analysis under qualified supervision to ensure best-practice was applied throughout. The resulting data (FID) was processed to derive the chemical shift and relative integration values, which were captured into a Microsoft® Excel 2010 spreadsheet to calculate the relative integration values of each sample run. Statistical analysis was performed in GNU PSPP version 085, the data was analysed using descriptive statistics and the non-parametric tests, Kruskal-Wallis and Mann-Whitney U-test (due to small data size and nature of distribution) at a statistical significance interval of α = 0.05. Results Natrum muriaticum LM1 samples sourced from a variety of make-to-order (MTO) and make-to-stock manufacturing environments produced almost universally distinct NMR spectra profiles in terms of chemical shifts and relative integration values of the CH2, CH3 and H2O signals, at an alcohol concentration of 20%, when compared to a Lactose LM1 control sample. When the NMR spectra of make-to-order (MTO) and make-to-stock (MTS) remedies were analysed and compared to each other in terms of chemical shifts and relative integration values of the CH2, CH3 and H2O signals, they were for the most part statistically distinct, but some anomalous results emerged. There was no statically significant difference in NMR spectra in terms of chemical shift, between the two samples produced in the same environment using the methodology to closely aligned to Organon (Hahnemann and O'Reilly 2001), yet in terms of relative integration values, they were statistically distinct. Conclusion The low alcohol percentage associated with the medicinal dosage of LM1 prepared for analysis failed to produce an OH peak on NMR spectra. In addition, it is not possible to identify the variables or indeed account for the nature of NMR spectra that are produced after sample analysis. This study concludes that while NMR was able to discern physico-chemical distinction between LM1 potency Natrum muriaticum remedies to control conclusively, this does not translate to practical application of NMR for quality control or remedy comparison for LM potencies at alcohol content levels, associated with medicinal prescription.
Determinants of key drivers for potable water treatment cost in uMngeni Basin
(2015-03-04) Rangeti, Innocent; Dzwairo, Bloodless; Barratt, Graham James
The study entailed the determination of key water quality parameters significantly influencing treatment cost in uMngeni Basin. Chemical dosage was used as a substitute for treatment cost as the study indicated that cost, in its monetary value, is influenced by market forces, demand and supply, which are both not directly linked to water quality. Chemical dosage is however, determined by the quality of water and thus provides a clear illustration of the effect of pollution on treatment cost. Three specific objectives were set in an effort to determine key water quality parameters influencing treatment costs in uMngeni Basin. The fourth objective was to develop a model for predicting chemical dosages. The first approach was analysis of temporal and spatial variability of water quality in relation to chemical dosage during production of potable water. The trends were explained in relation to river health status. For this purpose, time-series, box-plot, and the Seasonal-Kendal test were employed. The results showed that the quality of water significantly deteriorated from upstream to downstream in relation to algae, turbidity and Escherichia coli (E. coli). High mean range of E. coli (126-1319 colony count/100mL) and turbidity (2.7-38.7 NTU) observed indicate that the quality of water along the basin is not fit for human consumption as these parameters exceeded the target range stipulated in South Africa’s guidelines for domestic use. For water intended for drinking purpose, turbidity should be below 5 NTU, while zero E. coli count is expect in 100 mL. Among the six sampling stations considered along the uMngeni Basin, three dam outflows (Midmar, Nagle and Inanda) showed an improved quality compared with their respective inflow stations. This was expected and could be attributed to the retention and dilution effects. These natural processes help by providing a self-purification process, which ultimately reduces the treatment cost. While considering the importance of disseminating water quality information to the general public and non-technical stakeholders, the second objective of the study was to develop two water quality indices. These were; (1) Treatability Water Quality Index and (2) River Health Water Quality Index. The Treatability Water Quality Index was developed based on the Canadian Council Minister of Environment Water Quality Index (CCME-WQI). The technique is used to determine fitness of water against a set of assigned water quality resource objectives (guidelines). The calculated Harmonised Water Quality Resource Objectives (HWQRO) were used to compare the qualities of the raw water being abstracted at Nagle and Inanda Dam for the purpose of treatment. The results showed that Nagle Dam, which supplies Durban Heights, is significantly affected by E. coli (42% non-compliance), turbidity (20% non-compliance) and nitrate (18% non-compliance) levels. Wiggins Water Treatment Plant which abstracts from Inanda Dam has a problem of high algae (mean 4499 cell/mL), conductivity (mean 26.21 mS/m) and alkalinity (mean 62.66 mg/L) levels. The River Health Water Quality Index (RHWQI) was developed using the Weighted Geometric Mean (WQM) method. Eight parameters, namely, E. coli, dissolved oxygen, nitrate, ammonia, turbidity, alkalinity, electrical conductivity and pH were selected for indexing. Rating curves were drawn based on the target ranges as stipulated in South Africa’s guidelines for freshwater ecosystems. Five classes were used to describe the overall river health status. The results showed that the water is still acceptable for survival of freshwater animals. A comparison of the RHWQI scores (out of 100) depicted that dam inflow station (MDI(61.6), NDI(74.6) and IDI(63.8)) showed a relatively deteriorated quality as compared with their outflows (MDO(77.8), NDO(74.4) and IDO(80)). The third objective was to employ statistical analysis to determine key water quality parameters influencing chemical dosage at Durban Heights and Wiggins Water Treatment Plants. For each of the two treatment plants, treated water quality data-sets were analysed together with their respective raw water data-set. The rationale was to determine parameters showing concentration change due to treatment. The t-test was used to determine the significance of concentration change on each of the 23 parameters considered. Thereafter, the correlations between water quality parameters and the three chemicals used during treatment (polymer, chlorine and lime) were analysed. The results showed that the concentrations of physical parameters namely, algae, turbidity and total organic carbon at both treatment showed a significant statistical (p<0.05) reduction in concentration (R/Ro<0.95). This results implies that such parameters were key drivers for chemical dosage. From the results of the first three objectives, it is recommended that implementing measures to control physical parameter pollution sources, specifically sewage discharges and rainfall run-off from agricultural lands along the uMngeni Basin should assist in reducing the chemical dosage and ultimately cost. The fourth objective was to develop chemical dosage models for prediction purposes. This was achieved by employing a polynomial non-linear regression function on the XLStat 2014 program. The resultant models showed prediction power (R2) ranging from 0.18 (18%) up to 0.75 (75%). However, the study recommends a comparative study of the developed models with other modelling techniques.
Development of a model to predict bulking in full-scale wastewater treatment plants, and the impact of bulking in the receiving environment
(2021-05-27) Deepnarain, Nashia; Bux, Faizal; Kumari, Sheena; Reddy, Poovendhree; Stenström, Axel
Sludge bulking has been a continuous operational hurdle affecting the solids-liquid separation in wastewater treatment plants (WWTPs) worldwide. Excessive growth of filamentous bacteria is the primary and common cause of sludge bulking, which can have negative impacts on the wastewater treatment efficiency. Filamentous bacteria serve as the backbone structure of flocs which assist in the sludge settling process, however, their prolific growth result in slow sedimentation due to inadequate settling of flocs. The main focus of this research was to develop a model to assist in a clearer understanding of the bulking sludge phenomenon in relation to filamentous bacterial growth and to identify predictors of bulking in different biological nutrient removal (BNR) WWTPs. The growth of filamentous bacteria and sludge bulking in different WWTPs and its association with sludge bulking incidents were evaluated using different statistical models [viz. artificial neural networks (ANN), principal component analysis (PCA), cluster analysis and Decision Trees]. In addition, the effect of bulking on pathogen discharge and its potential impact on the community was assessed using a microbial risk assessment model. A total of seven WWTPs were investigated to identify the most common and dominant filamentous bacteria during bulking and non-bulking periods. A total of ten filamentous bacterial species were identified in this study with their dominance varying across the selected WWTPS during the sampling period. Based on the filament index scale ranging from 1 (None filament) to 7 (Excessive filament), the developed ANN model predicted sludge volume index (SVI) in relation to the abundances of ten filamentous species as model inputs. Among the filamentous bacteria identified, Eikelboom Type 0041 attained the highest impact on SVI, followed by Gordonia spp., Nostocoida limicola, and Thiothrix spp. Developing a model for a WWTP, with proper calibration and validation against plant operational data, can allow for proper evaluation of filamentous bacteria associated to bulking, with effective mitigating strategies. Hence, in this study, a Decision Tree model was further implemented as a novel approach in the form of a case study to evaluate the effect of influent wastewater characteristics and plant operational parameters on the dominant filamentous bacteria and sludge bulking for prediction and control. Various factors such as pH, temperature, dissolved oxygen (DO), sludge retention time (SRT), food-to-microorganisms (F/M) ratio, soluble chemical oxygen demand (sCOD), total COD (tCOD), NH4 + -N, total Kjeldahl nitrogen (TKN), phosphorus as phosphate (PO4 3- -P), TP, and total suspended solids (TSS) were considered to have an impact on filamentous dominance. High bulking incidents were observed during long SRT and nutrient deficient (low F/M) conditions. However, a negative correlation was observed with soluble sCOD and ammoniumnitrogen (NH4-N). Type 0092 was the dominant species largely responsible for sludge bulking in the selected plants, which prevailed at low F/M (< 0.08 kg COD/kg MLSS d-1 ) conditions. The secondary filaments Candidatus Microthrix parvicella increased in their abundance at low temperature (< 15.5°C), causing an increase in SVI at lower ambient temperatures. In addition, an increase on Thiothrix spp. was linked with the unbalanced ratio between readily biodegradable COD and nutrient conditions. The last objective of this study provided an assessment from an environmental health perspective, by investigating the impacts of bulking on the receiving environment, using a quantitative microbial risk assessment (QMRA) approach. This was done by studying the difference in selected microbial pathogen abundance during bulking and non-bulking conditions using qPCR. Salmonella was the most dominant species of the investigated microorganisms, during the study period (2270– 96733 copies ng-1 of DNA) followed by E. coli (4133 – 76847 copies per ng of DNA); whereas, Mycobacterium was the least (542 – 3340 copies ng-1 of DNA). During high bulking with SVI >200 mL g-1 , positive correlations were found between the selected pathogens in the final effluent. The QMRA model was applied to investigate the safety of treated effluent for (a) children, women, and men during recreational activities, (b) farmers during irrigation practices, and (c) consumers of edible plants (vegetables). The QMRA values during all bulking events exceeded the tolerable risk of 10-4 (i.e. less than one case of infection per 10 000 people) per year, as recommended by the world health organization (WHO). In addition various disinfection scenarios such as chlorination, ultraviolet (UV) and ozonation were tested to control the risks associated with pathogenic bacteria, for further information of safe disposal and reuse of the treated effluent. The application of UV provided the most effective treatment to reduce the pathogenic bacteria, except for the case of children that were exposed to Salmonella infection. To the best of my knowledge, the probable health risks associated with the discharge or reuse of WWTPs effluents under different sludge bulking events have not yet been systematically evaluated using QMRA. This research can potentially lead to the development of appropriate model systems for bulking control in full-scale WWTPs, while highlighting some of the significant contributors, environmental impact and mitigation strategies. The outcomes of this research will contribute to the current global body of knowledge in relation to predictive models for filamentous bulking control in full-scale WWTPs.
The effect of various homoeopathic potencies of the antigenic component of a Newcastle disease vaccine on the immune response of broiler chickens to the Newcastle disease vaccine
(1998) Mostert, Ronell; Ross, Ashley Hilton Adrian; Thomson D. K.
Two hundred and ten (210) commercially produced Hubbard x Peterson broiler chickens were randomly divided into 5 groups of 42 chickens when they were 14 days old. Each group was divided into two replications. Twoseparate rooms of a poultry house were used to house the chickens, and each room housed one replication of each group. Group 1was not vaccinated and acted as an indicator of extraneous Newcastle disease. Group 2,3, and 4 received 12C,30C and 200C potencies ef the antigenic component of the vaccine respectively. Hcmceopcthic remedies were administered in the drinking water from ,day 14 to day 42. Group 5 was the vaccinated control group and received alcohol in the same concentrations as the groups receiving treatment from day 14 to day 42. On day 14 the birds were vaccinated subcutaneously in the retronuchal area with 0.5ml of a killed oil emulsion vaccine. Haemagglutination Inhibition tests were performed to quantify the immuneresponse to the vaccine on blood samples taken from all the birds on days 14, 28 and 42. Three way factorial analyses with groups, rooms and days as factors was carried out USingproe GLM. The daily administration of homoeopathic dilutions of the antigenic component of the Newcastleibition
The effects of eleutherococcus senticosus on egg laying hens
(1998) Bolling, Birgit; Strydom, G.S
The purpose of this investigation was to evaluate the effects of Eleutherococcus senticosus on the number of eggs, the weight of the eggs, the quality of the eggs (height of the albumin; colour of the egg yolk) laid, as well as the mortality of the hens fed Eleutherococcus senticosus for 28 days. It was hypothesized that Eleutherococcus senticosus would increase the number of eggs, the weight of the eggs, improve the quality of the eggs laid and decrease the mortality rate of the hens. The study design is a two by two experimental design. The 1440 egg laying hens, which all came from the same breeding farm, were housed by Golden Lay at Whitelodge. Seven hundred and twenty hens made up the treatment groups receiving Eleutherococcus senticosus. Seven hundred and twenty hens made up the placebo groups receiving normal water. In the first week no medication was given to the treatment group. In the second, third, fourth, fifth week 300 ml of E'leutherococcus senticosus was introduced daily into the drinking water of the treatment group. The eggs were collected, counted and weighed manually on a daily basis. Once a week 72 eggs were collected randomly for quality testing ( height of the albumin, colour of the egg yolk). The height of the albumin was measured by means of a tripod. The colour of the egg yolk was compared to the Roche colour chart. In the sixth and seventh week the treatment group received no medication.
Evaluation of antibiotic-resistant bacteria and genes associated with tuberculosis treatment regimens from wastewater treatment plants in South Africa
(2022-05-13) Mtetwa, Hlengiwe Nombuso; Reddy, Poovendhree; Kumari, Sheena K.; Bux, Faizal
Essential components of a strong public health system include an efficient surveillance system which helps in early detection and prevention of infectious diseases. This is particularly important for tuberculosis (TB) and multidrug-resistant tuberculosis (MDR-TB), due to increasing globally infections and the associated economic burdens. TB and MDR-TB infections are high in several countries, with South Africa contributing almost 3% of total infections globally. This advocates for improved surveillance systems to help health authorities respond effectively in developing effective policies for managing and controlling diseases. The reliance on clinical case reports, hospital admissions and clinical surveys, as surveillance methods, has proven to be a challenge in developing countries like South Africa, where there are other competing interests for scarce resources. The development and implementation of alternative surveillance tools for identifying disease severity, the emergence of novel strain and resistance patterns is, therefore, a top priority. One such strategy is the use of sewage or wastewater-based analysis, commonly referred to as wastewater-based epidemiology (WBE), which has received attention lately due to its role in developing early warning and surveillance of SARS-CoV-2 (COVID-19) infections. This study evaluates, method development for utilizing WBE approach for monitoring TB and MDR-TB infections via the detection and quantification of tuberculosis-causing mycobacteria and genes (ARGs) associated with resistance to TB treatment in untreated wastewater. Furthermore, the study contributes towards the understanding potential TB transmission through wastewater. To achieve these, conventional and advanced polymerase chain reaction (droplet digital PCR) assays were optimized for the detection and quantification of total mycobacteria, members of the Mycobacterium tuberculosis complex (MTBC) and ARGs associated with resistance to first and second-line TB drugs. The mycobacteria targeted in this study were total mycobacteria, M. tuberculosis complex, M. tuberculosis, M. africanum, M. bovis and M. caprae. The ARGs (and the antibiotic they encode resistance to, in parenthesis) targeted in this study were; katG (isoniazid), rpoB (rifampicin), embB (ethambutol), pncA (pyrazinamide), rrs (streptomycin), gyrA (ofloxacin), gryB (moxifloxacin), atpE (bedaquiline), ethR (ethionamide), eis (kanamycin/amikacin). Untreated and treated (post-chlorination) wastewater samples from three wastewater treatments plants (WWTPs) in the city of Durban, South Africa were used for this study. All wastewater samples (untreated and treated) analyzed in this study contained total mycobacteria and MTBC at varying percentages per WWTP studied. The human and animal MTBC pathogens such as M. tuberculosis, M. bovis and M. caprae showed a similar prevalence, except for M. africanum, which was less common compared to the others. The highest median concentration detected in untreated wastewater was 4.9(±0.2) Log10 copies/ml for total mycobacteria, 4.0(±0.85) Log10 copies/ml for MTBC, 3.9(±0.54) Log10 copies/ml for M. tuberculosis, 2.7(±0.42) Log10 copies/ml for M. africanum, 4.0(±0.29) Log10 copies/ml for M. bovis and 4.5(±0.52) Log10 copies/ml for M. caprae. A statistically significant difference (p-value ≤ 0.05) in concentrations of each organism was observed between the plants. A significant reduction in copy numbers from untreated to treated samples were observed. However, the log reduction in each WWTP did not show any statistically significant differences when compared between the three WWTPs, irrespective of the organism or group of organisms (p-value ≥0.05). Furthermore, all targeted ARGS were detected in all samples analyzed at varying concentrations. The most abundant ARG in the untreated wastewater was rrs, associated with resistance to the aminoglycosides, specifically streptomycin. In contrast, pncA gene associated with resistance to the TB drug pyrazinamide was the least detected. Furthermore, the resistant gene associated with bedaquiline (aptE) was also detected in all samples, albeit at low concentrations. This antibiotic is a new addition to the TB treatment regimen in South Africa and it is concerning that resistance has already been detected. The occurrence and concentration of these ARGs were lower in the treated wastewater in most instances, ranging from 1 log copy/ml to over 4 log copies/ml except for selected genes at few instances. The study makes novel major contributions, firstly, the detection of M. tuberculosis complex members in the untreated wastewater at high concentrations signifies a potentially high prevalence of TB in the study area. Secondly, the detection of M. africanum in South African wastewater also signifies that some of the TB infections in the communities could be caused by this pathogen. M. africanum is the main causative agent of TB in West Africa but is not frequently reported clinically in South Africa. Finally, the presence of diverse ARGs associated with TB drugs also points towards an association between the drug use and resistance profile in the area. These results further support the potential application of WBE to gather data on MDR-TB within communities with limited or no clinical data. The detection of the aptE gene also shows that resistance to the new drug, bedaquiline, could already be developing in the communities. The study also observed that the wastewater treatment plant configuration did not significantly influence the removal of these mycobacteria. Furthermore, selective conditions in the WWTPs may contribute to increased concentrations of ARGs during the treatment processes as indicated by increased concentrations for certain ARGs detected in the treated wastewater. This warrants further studies to determine whether the genes detected in the effluent are extracellular or carried in viable microorganisms, to assess the viability and infectivity of the microorganisms carrying these genes in the effluent samples and therefore the potential public health risks associated with the exposure to wastewater. In conclusion, this study establishes the potential of molecular surveillance of wastewater for monitoring TB and MDR-TB infections in communities and supports the use of WBE as a public health strategy to combat infectious diseases.
The evaluation of the quality of sanitation and stored water for domestic use in the Umlazi P Section informal settlement
(2021-12-01) Shangase, Simangaliso Idiom; Pillay, Pavitra; Ndlovu, T. S.
Background The quantity of water delivered and used for households is an important requirement for life as well as basic personal hygiene. Simple hygiene measures have become paramount due to corona-virus 2019 (Covid-2019). South Africa still lacks basic infrastructure to supply adequate quantities of water to all. This problem is exacerbated in the growing informal settlements where infrastructure is limited. A growing awareness shows contamination of water can occur during collection and storage. This results in the deterioration of water quality to the extent that the water becomes undrinkable. Contributing factors include the cleanliness of storage containers as well as the environment in which they are stored. The aim of the study This study aimed to investigate the quality of stored water and the related handling of storage vessels after collection for domestic use at the informal settlement of the Umlazi P Section, in the south-west of Durban. The study objectives The objectives of the study were to determine the knowledge and awareness of water contamination and how water resources can be protected. To discover the exposure of drinking water to waterborne pathogens due to poor storage and hygiene practices using a questionnaire. To test stored water samples for pathogenic organisms using acceptable laboratory methods and compare the findings for compliance with the South African Water Quality Guidelines for domestic use (SANS 241: 2015). To test the pH levels and macroscopic appearance of stored water in order to assess the extent of natural organic and corrosive substances dissolved in domestic water. Study Design This was a descriptive cross-sectional quantitative study aimed at analysing data of exposure of Umlazi P section residents to contaminated water resources. Data collection entailed the administration of a questionnaire to 269 participants, including the laboratory analysis of water samples collected from water storage containers used in each household. Data collection tools The questionnaire was used to obtain information on behavioural characteristics of the participants concerning their knowledge, awareness of practices related to water contamination, storage and waste management. The laboratory analysis of stored water samples included testing for the presence of pathogenic organisms, testing of pH and an analysis of the macroscopic appearance of the water. Laboratory findings were compared in compliance with the South African Water Quality Guidelines for domestic use. Results Majority of the participants (98.5%) indicated they use municipal water services for their daily needs. It was found that most residents (88.1%) did not have any prior education on water storage and (76.6%) indicated a lack of understanding of water contamination. There was a lack of proper hand hygiene and handling of stored water among 48 households (18%). Almost all respondents indicated that they stored their domestic water in buckets which were kept closed when not in use, and (83.3%) indicated that they cleaned the storage containers by washing it in cold water only. It was found that half of the participants are unemployed and 32% of them use pit latrines as toilets. Most of the respondents found the taste of the water palatable. A positive total coliform count was found among 13 (5%) households in the study, rendering their drinking water a high risk for domestic use, 9/13 of these households used pit latrines. The high-risk coliform count, despite it only accounting for 5% of the population is of great concern. Testing results also showed a zero count for Escherichia coli (E.coli) making drinking water acceptable in terms of faecal coliform bacteria. Discussion and Conclusion Results indicate a clear need to develop educational programmes that will enhance knowledge of water contamination to improve water quality. These educational programmes need to focus on hygiene practices to minimise water contamination. Infrastructure development remains a key recommendation as it plays an important role in the removal of human faecal waste in the distribution of water to communal taps. The infrastructure development must entail the provision of more taps to avoid overcrowding and provision of flushable toilets as an effective waste removal method. While the Municipality has played a role in the removal of solid waste, more needs to be done to accommodate all residents in informal settlements to prevent illegal dumping which increases environmental pollution. Considering the variability of water storage periods (between a week to a month) due to the distance between settlements and collection points, the provision of low-cost quality storage containers and treatment chemicals by the Municipality is recommended. The Department of Housing, Water and Sanitation, Health, Education and other Non-Governmental organisations need strengthening of inter-sectoral collaboration to improve the quality of life in informal settlements. The National Water Act of 2003 outlines the role of local government concerning water resources of equitable allocation of water to all citizens and redistribution as well as removal of discriminatory laws that prevent equal access to water (Republic of South Africa – Government act 61 of 2003).
Genetic diversity and development of a rapid molecular detection method for protozoan parasites in raw and treated wastewater
(2024) Hlongwa, Nonsikelelo Precios; Pillai, Sheena Kumari Kuttan; Amoah, Isaac Dennis; Reddy, Poovendhree; Bux, Faizal
Protozoan parasites can cause a wide range of diseases in both humans and animals. Despite this, little is known about their genetic diversity in the environment, particularly in wastewater. Current methods of detecting protozoan parasites are time-consuming and expensive, limiting our ability to monitor potential risks associated with their discharge into the environment. Consequently, this study aimed to determine the genetic diversity of protozoan parasites in wastewater treatment plants and to develop a rapid and affordable technique for their detection and quantification from environmental samples. Shotgun metagenomics and 18S rRNA gene sequencing were employed to assess the diversity of protozoan parasites in influent (untreated) and effluent (treated) wastewater samples collected from different geographical locations within South Africa. Furthermore, rapid fluorescent and colorimetric loop-mediated isothermal amplification (LAMP) methods were developed for their detection from different environmental matrices. The LAMP methods were then compared with the established methods, including quantitative PCR and digital PCR for their sensitivity and feasibility. Additionally, the study has also evaluated oocyst concentration and DNA extraction methods to maximize oocyst recovery from wastewater samples resulting in a recovery rate of 64.1%. Using 18SrRNA analysis, it was found that protozoan diversity (Shannon index, P-value=0.003) and taxonomic composition (PERMANOVA, P-value=0.02) were significantly associated with WWTP location and treatment stage (P-value=0.003). An abundant number of free-living, parasitic, and potentially pathogenic protists was observed in the untreated wastewater samples, including Alveolates (Apicomplexa and Ciliophora), Excavata (Discoba and Parasalia), and Amoebozoa (Entamoeba and Acanthamoeba). In contrast, treated wastewater samples were found to be dominated by fungi and algae. In a subset of samples (n=3), shotgun metagenomics analyses revealed the presence of protozoa of public health importance, including Cryptosporidium spp. All untreated wastewater samples studied were found to contain Entamoeba hystolitica, Blastocystis hominis, Naegleria gruberi, Toxoplasma gondii, Cyclospora cayetanensis, and Giardia intestinalis. The functional pathways associated with pathogenic protozoa were classified into thiamine diphosphate biosynthesis III, Heme biosynthesis, methyl erythritol phosphate (MEP), Methylerythritol 4-phosphate pathway, and pentose phosphate pathway. The optimized LAMP methods (colorimetric and fluorescent) successfully detected Cryptosporidium parvum (GP60 gene) and the Cryptosporidium genus (SAM gene) from environmental samples with 100% specificity. Both methods demonstrated a high sensitivity, with the same limit of detection (LOD) of 1.1 copies of C. parvum per 25 µl reaction (0.02 ng/µl). A comparison of LAMP, ddPCR, and qPCR revealed that ddPCR had the highest sensitivity, with a limit of detection (LOD) of 1 copy/reaction and 100% true positives followed by fluorescent LAMP with a LOD of 1.1 copies and 75% true positives, while qPCR was the least sensitive with a LOD of 14 copies and 100% true positives. All three methods showed good linearity (> R2 =0.9) over a wide dynamic range of C. parvum concentrations. The study further revealed that fLAMP is the most affordable ($12.46/sample), followed by qPCR ($28.19/sample), and ddPCR ($67.29/sample). Using the optimized protocol, C. parvum and Cryptosporidium spp. were detected in 50–85% (n = 60) of environmental samples (treated and untreated wastewater, sludge, and surface water) in comparison to 58–98% (n = 60) detected by ddPCR. Additionally, these findings suggest that LAMP can be an effective and affordable method for monitoring protozoan parasites in the environment. The findings of this study provided valuable insights into the genetic diversity of protozoan parasites in wastewater, which is crucial for advancing our understanding of disease epidemiology, evolution, and ecology. Furthermore, the findings of this study have important implications for monitoring pathogens in wastewater, especially in countries with limited resources for monitoring and managing waterborne diseases.
Hygiene practices as a contributing factor to diarrhoea in preschool children in Mpumalanga Township, KwaZulu-Natal
(2021-05-27) Ntshangase, Samukelisiwe Nomonde; Ghuman, Shanaz; Haffejee, Firoza
Background: Diarrhoeal disease is reported by the World Health Organisation (WHO) as the second leading cause of mortality in children under five years old, and worldwide is responsible for the deaths of almost 525 000 children annually. Diarrhoea is defined as the passage of three or more loose or liquid stools per day, or more frequent passage than is normal for the individual and can last for several days. Diarrhoea is typically a symptom of an infection in the intestinal tract, caused by a variety of bacteria, viral and parasitic organisms. The disease is spread through contaminated food or drinking water or from person-to-person as a result of poor hygiene practices. Acute diarrhoea is a major cause of hospitalisation in South Africa, especially in children under two years of age. Diarrhoea is the main cause of morbidity and mortality in KwaZulu-Natal, even though case fatality decreased between 2014/15 and 2015/16. South Africa has improved the health and well-being of children through the introduction of the rotavirus vaccine into the National Immunisation Programme in 2009, the only known preventative measure against rotavirus diarrhoea. Aim/Objectives: The study aimed to determine if hygiene practices of parents/guardians and ECD educators contributed to diarrhoea in children attending the centres. Interdependent factors related to diarrhoea in children were also investigated. The objectives of the study included determining the prevalence of diarrhoea in children five years and under at ECD centres in Mpumalanga Township, KwaZulu-Natal; identifying risks factors that may contribute to diarrhoea in children; and assessing the knowledge, attitudes and practices of ECD educators and parents/guardians to diarrhoea and hygiene. Methodology: A descriptive cross-sectional study design was conducted using self-administered questionnaires at the research tool. The study was done at ten Early Childhood Development (ECD) centres in Mpumalanga Township, KwaZulu-Natal, South Africa. The total number of centres registered with the Department of Social Development in the area was 41 at the time of the study, with the total of educators approximating 177 and 3326 children attending the ECD centres. Simple random sampling was used in order to achieve a degree of accuracy and representativeness. The parents/guardians were selected from the same schools that were randomly selected for the educators. To achieve a 95% confidence level, respondents were invited to participate having signed informed consent. Statistical analysis was performed using SPSS version 26.0. Frequency distribution of categorical variables and means, standard deviation and ranges of continuous variables were calculated. Various graphs and tables were used to illustrate variables. The Pearson’s Chi-squared test was used where applicable for bivariate associations between categorical variables. Multivariate regression modelling was done with the inclusion of relevant covariates. Odds ratios were calculated for binary outcome variables. Confidence intervals of 95% were calculated and p values < 0.05 were considered statistically significant. Results: A total of 385 parents/guardians of 427 children attending ECD centres and a total of 121 ECD educators answered the questionnaires. The results indicated that 91.6% (n=350) of parents/guardians had flushing toilets and all the ECD centres had flushing toilets. Over 87.2% (n=333) parents/guardians reported that the toilets were indoors and 86.8% (n=105) ECD educators indicated that the centres had indoor toilets. The data revealed that over 60% (n=210) of parents/guardians said their child uses the toilet and 22.8% (n=76) had children who used nappies, thereby disposing the stools in the municipal collected waste. Only 0.9% (n=3) of parents said they buried the stools and 3.6% (n=12) said they left the child’s stools in the open. Drinking water was easily accessible in this study population as households had indoor taps (n=311, 80.8%), outdoor tap on the premised (n=70, 18.2%) and ECD centres indoor taps (n=109, 90.1%). Approximately 85% (n=307) of parents/guardians washed their hands more frequently after defecating when there was an indoor tap. Furthermore, parents/guardians who had handwashing sinks closer to the toilet washed their hands more frequently compared to those with handwashing sinks furthest (p=0.000). The study found that parents/guardians with a tertiary qualification were five times more likely to seek medical care than parents/guardians with a primary education education (OR=5.201, 95%CI=1.48-18.28, p=0.010). The administration of ORT was consistent across all levels of parental/guardian education (primary school, secondary school and tertiary). Homemade oral rehydration solution was mostly administered by parents/guardians with primary (n=5, 20.0%) and secondary education (n=21, 19.3%) compared those with tertiary education. The mean number of children under five years who had diarrhoea in the 12 months preceding this study was 1.23 (SD=0.53). Cryptosporidium infection was the likely cause of the watery diarrhoea in this population since rotavirus immunisation was given to the children. Conclusion: This study found that children were more likely to get diarrhoea from other children, compared to adults. How parents/guardians washed their hands was 1.239 times likely to contribute to children under the age of five getting infected with diarrhoea. The p-value of 0.010 was obtained in the association of type of toilet in the household and a child having diarrhoea. Knowledge around diarrhoea must be strengthened, more so in prevention, and when seeking medical care. Caregivers should be encouraged to have oral rehydration treatment readily available, to be used as needed.
Microbiological assessment of water quality and prevalence of waterborne diseases in rural areas of Masaka, Rwanda
(2014-05-28) Uwimpuhwe, Monique; Barratt, Graham James; Reddy, Poovendhree; Bux, Faizal
Waterborne diseases represent substantial global burden of disease and children under the age of five are more susceptible to these diseases compared to adults. The aim of this study was to determine the microbiological quality of Nyabarongo River water used for domestic purposes, women’s knowledge, attitudes and practices (KAP) on water usage and waterborne diseases and its link to the diarrhoea outbreaks experienced in two rural communities: Rusheshe and Ayabaraya of Masaka in Rwanda. A total of 35water samples were collected from Nyabarongo River and from study households which used slow sand filtration (SSF) or Sûr’Eau as treatment methods and analyzed for total coliform and faecal coliform indicators. For household samples turbidity was also analyzed. Retrospective records from Masaka Health Centre were reviewed to determine the prevalence of waterborne diseases from the study areas during 2010. Further, a structured questionnaire was administered to 324 women residents of the study areas to elicit information on their KAP on water handling and waterborne diseases. SPSS Predictive Analytic Software (PASW) Statistics version 18.0 (IBM, Somers, NY) and STATA Release (Version 11.0, College Station, Texas USA) were used for data analysis. Results showed that the mean values of total and faecal coliforms of river and household water samples were above the WHO and Rwandan recommended guidelines. The mean values of total coliform and faecal coliform were significantly lower (p ≤ 0.05) in both filtered and Sûr’Eau treated water than in river water. No statistical differences of means were observed for both total coliform and faecal coliform counts between samples taken from filtered and Sûr’Eau treated water containers (p=0.80 (TC) and p = 0.56 (FC). However, turbidity values were significantly lower in filtered water using SSF than in Sûr’Eau treated water samples (p =0.002). Out of 2814 records form Masaka Health Centre during 2010, 160 cases were identified as having diarrhoeal diseases. Furthermore, respondents who used Nyabarongo River as source of water were more likely to have symptoms of diarrhoea (OR =5.35; CI: 2.12 - 14.46; p <0.05). The frequency of diarrhoea were significantly higher among people who did not wash hands before food preparation (p = 002) and after using a toilet (p = 0.007) than among those who did. There was a statistically significant association of level of education levels and drinking water treatment practices at the household level (p < 0.05). Respondents with primary school education only and those with high school education were more likely to wash their hands after using a toilet (OR= 5.24, CI 1.42-19.38, p =0.01 and OR = 7.15, CI = 1.79 -28.62, p=0.01, respectively) than those who did not attend school. No significant associations were identified between educational levels and washing hands before food preparation. The findings of this study points to the facts that water sourced from Nyabarongo River is unsafe for human consumption even after prescribed treatment, such as the use of SSF and Sûr’Eau, and could increase the prevalence of waterborne diseases and therefore calls for urgent provision of potable water. Women in the study areas had limited knowledge regarding water storage practices for prevention of household water contamination and this; underscore the need for more water handling practices and hygiene education in rural communities.
Occurrence and variations of cryptosporidium and giardia in wastewater treatment and receiving river basins
(2020-06-10) Adeyemo, Folasade Esther; Stenström, Thor Axel; Reddy, Poovendhree; Bux, Faizal
Wastewater disposal may be a source of environmental contamination of Cryptosporidium and Giardia. Releasing untreated wastewater into the environment may result in waterborne or foodborne outbreaks. The presence of Cryptosporidium and Giardia in wastewater is of major concern in human health when wastewater is used for irrigation. The infections influence morbidity with several cases of illnesses including diarrhoea and other gastrointestinal diseases. Mortality is of high incidence, especially among the immunocompromised. Worldwide, Cryptosporidium and Giardia are well-documented in outbreaks from drinking water, recreational water and food. The aim of the study was to demonstrate the level of occurrence of Cryptosporidium and Giardia in selected wastewater treatment plants (WWTP) as well as receiving water bodies and to account for the use of wastewater in irrigation in Ethekwini, South Africa. The occurrence and reduction of Cryptosporidium and Giardia in the WWTPs were investigated, the species determined and their viability assessed. The correlations between E. coli, Enterococci and the concentration of the protozoan parasites were included. Additional specific objectives relate to the effect of effluent chlorination, the seasonal variation and the impact on crops based on the occurrence and quantities of Cryptosporidium and Giardia in the irrigated water. Influent water concentrations reflect the endemicity level in the connected population. This together with water from the intermediate treatment steps and effluent samples in four wastewater treatment plants were investigated monthly (sampled September 2015-April 2016). Conventional filtration and centrifugation methods were used for the detection and enumeration of Cryptosporidium and Giardia. Immuno-magnetic separation (IMS) on concentrated water samples was performed using Dynal anti-Cryptosporidium and anti-Giardia beads and immune-magnetic antibodies and examined with epifluorescence microscopy. In addition, molecular methods were used to differentiate the species of Cryptosporidium and assemblages of Giardia based on polymerase chain reaction (PCR) and quantitative polymerase chain reaction (qPCR). The influent counts for Cryptosporidium oocyst varied between 1.83 to 3.02 log10 oocysts/L, with a corresponding concentration of Giardia cysts ranged from 2.39 to 3.15 log10 cysts/L. The overall mean reduction over the wastewater treatment plants was in the range of 1.35 log10/L to 1.61 log10/L and 1.35 log10/L and 1.62 log10/L for Cryptosporidium and Giardia respectively. Cryptosporidium and Giardia were present in the effluents from all wastewater treatment plants. In general, weak negative to poor positive correlation was found between E. coli, faecal enterococci and the presence of Cryptosporidium and Giardia in all WWTPs. Both Cryptosporidium and Giardia were further detected at the downstream sampling points. The PCR and qPCR speciation did not compare with the traditional specific antibody and microscopic counts. The 18s rRNA gene-based nested PCR resulted in 13 (27%) out of 48 wastewater sample positive for Cryptosporidium. C. parvum was the dominated species followed by C. hominis. In ß-giardin based qPCR, all wastewater samples were positive for Giardia Assemblage A and Giardia Assemblage B. The impact of wastewater on the rivers signifies the possible health risks associated with the use of the effluents for agricultural purposes and the receiving water bodies’ use for domestic and recreational activities. Crops irrigated with the river water from the study area gave concentrations of Cryptosporidium and Giardia in spinach samples of 67 to 480 and 3 to 27 per 100 g vegetable respectively. The contamination of the fresh vegetables analysed mainly arose from the use of the effluent from the WWTP B and the receiving river water used for irrigation. In a pilot study researching the effect of chlorine and UV irradiation, distilled water and wastewater samples spiked with environmentally derived Cryptosporidium oocysts and Giardia cysts which were exposed to different doses of chlorine and UV with different exposure times. Viability quantification and detection was done with microscopy and flow cytometry using two vital dyes, namely Syto9+PI and DAPI+PI. Giardia was affected to a much higher degree than Cryptosporidium, both in relation to chlorination and UV, where in the latter case close to zero percent remained viable even after a low dose. Cryptosporidium was found to be resistant to chlorination but responded well to high UV doses. This is in line with similar earlier investigations done in drinking water. In the comparative assessment between the vital dyes, DAPI+PI dyes gave a lower mean percentage viability value than Syto9+PI; and flow cytometry gave a higher mean percentage value than microscopy. The presence of Cryptosporidium and Giardia in all treated effluents from all investigated wastewater treatment plants exceeded World Health Organisation’s (WHO) risk-based values and South African National Standard’s (SANS:241) limit for raw water and irrigation respectively. Enforced regulations and alternative wastewater treatment methods may ensure a higher level of safety for the environment. Additional information on the occurrence of Cryptosporidium and Giardia in wastewater samples, which is currently lacking or limited in South Africa, will further increase our understanding in formulating risk assessment strategies to map out the level of infection to exposed population
Poor sanitation and hygiene practices : a case of eZimangweni community in Inanda, eThekwini Municipality in KwaZulu-Natal
(2023-05) Thuthu, Zungezi Wiseman; Ghuman, Shanaz; Jinabhai, Champaklal Chhaganlal
Purpose of the study - Access to water, proper sanitation facilities and good hygiene practices are critical in disease prevention and health in the community. The right to basic services, comprising of adequate shelter and water, are entrenched in the Republic of South Africa’s Constitution (1996) with the rights to access to both basic water supply and basic sanitation required to guarantee sufficient water and an environment not harmful to health or well-being recognized in the Water Service Act of 1997. Research Problem - In South Africa access to water, sanitation and hygiene (WASH) services, remains inadequate and inequitable in many peri-urban and rural communities. Discrimination related to rising unemployment and the remnant of Apartheid separated service delivery system resulted in unequal access to WASH services. About “50% of the world’s population” live in urban and sub-urban areas, and a number of these areas have a deficiency on access to clean water and sanitation necessary for proper health and well-being. Research Methods and Design - The study employed a quantitative study design. Descriptive cross-sectional study was conducted among households in Ezimangweni in Inanda between March and May 2021. A sample of 170 households was selected by means of the systematic random sampling strategy, where the margin of error was set at 5%. The research was aimed at assessing poor sanitation and hygiene practices in the community of Ezimangweni in Inanda, examine community knowledge related to health and hygiene practices, identify root causes for poor sanitation and assess challenges faced by community members regarding sanitation facility provided. Findings -The research revealed that sanitation and hygiene was very poor in the study area. This is supported by local Community Health Centre reporting 100% of cases of diarrhoea reported on a monthly basis, 66.7% cases of children reporting with blood in the stool and 33.3% of children with Dysentery and 33.3% cases amongst children vomiting. This study has established a strong relationship between poor sanitation, hygiene practices and type of diseases prevalent in the study area. Conclusion - The research has emphasised the vital role of providing sustainable WASH services to communities in order to prevent transmission of diseases and mitigate spread of water-borne illnesses.
The risk factors of soil-transmitted helminth infections : a need for appropriate measurement methods
(2018) Amoah, Isaac Dennis; Stenström, Thor-Axel; Reddy, Poovendhree; Seidu, Razak
Soil-transmitted helminths are a major health concern, especially in tropical and sub-tropical regions. Poor sanitation and poverty are major pre-disposing factors contributing to increase in infections. Infection with STH is mainly through exposure to water, soil and food contaminated with the eggs of these parasites. Accurate detection and quantification of STH eggs in environmental samples is therefore critical for the determination of infection risks from exposure. Accurate detection of these eggs is also important in the adoption of risk reduction strategies. This thesis presents the development of a revised method for the accurate detection and quantification of STH eggs in different environmental matrices, such as wastewater, sludge etc. It further presents the application of this method in the comparative determination of STH egg reduction efficiencies of centralized wastewater treatment plants and decentralized wastewater treatment (DEWATS) plants in Durban, South Africa and Maseru, Lesotho. The concentration of viable STH eggs in dried sludge from Durban, South Africa and Dakar, Senegal was also determined and compared with both WHO guidelines and South African national standards for sludge reuse. The risks of infection with STHs for different populations exposed (directly and indirectly) to wastewater, wastewater contaminated surface water and sludge were determined using both quantitative microbial risks assessment and epidemiological approaches. Despite the plethora of methods available for the detection and quantification of STH eggs in the environment there is no internationally accepted method, however the most commonly used methods are based on the principles of sedimentation, differential flotation and microscopy. These are mainly adaptations of the WHO and USEPA methods. These methods were found to be similar with a few differences which affected the recovery rates reported. However, the major challenges with the conventional methods are the time needed for sample analysis and the use of reagents that could possibly affect the recovery of viable STH eggs. A new revised method was developed based on review of literature and laboratory experiments. In this method the heterogeneity of environmental samples was accounted for by the development of different pre-processing steps, involving the use of detergents to aid in the separation of eggs from particles in samples such as sludge, UD waste and untreated wastewater. Additionally, the use of sieves of different pore sizes ensured that the number of debris on the microscope slides was reduced considerably. The use of these sieves also reduced the time need for sample analysis, due to the elimination of the spontaneous sedimentation step, which is commonly used. This spontaneous sedimentation step takes between 12-24 hours therefore prolonging the time needed for sample analysis. Reagents such as acetoacetic acid and ethyl acetate were found to result in considerable loss of egg viability after just 5 minutes of exposure. This new method therefore does not involve their usage. The elimination of the use of acetoacetic acid and ethyl acetate step also reduces the number of steps involved in sample analysis. This reduces room for error as well as helping in fast analysis of samples. In addition to a much faster sample analysis the method has recovery percentages of 80.25% to 97.63% in sludge and wastewater samples respectively, with sensitivity of 2-3 eggs per liter in wastewater samples and 5-7 eggs per 20 gram of sludge. Exposure to STH eggs in the environment is mainly through wastewater, either treated or untreated, this exposure could therefore be eliminated through wastewater treatment. Centralized wastewater treatment systems are the most favored treatment options globally. These centralized treatment systems incur high cost of construction, maintenance and operations which may hamper the robustness in developing countries and rural areas. One of the most widely used alternative means of wastewater treatment is the anaerobic baffled reactors (ABRs) and planted gravel filters (PGFs) (collectively referred to as DEWATS in this thesis), which have been considered as low cost, effective wastewater treatment options. However, there is lack of comparative assessment of the STH egg removal efficiency of these two different wastewater treatment approaches. Eggs of Ascaris spp, hookworm, Trichuris spp, Taenia spp and Toxocara spp were the commonly recorded STH eggs in the untreated wastewater at the inlets of the centralized wastewater treatment plants as well as the DEWATS plants (except for Toxocara spp). There was variation in STH egg concentrations between and within the study areas, indicating difference in STH infections among the populations both in Durban and Maseru. STH egg removal varied between and within the different wastewater treatment plants as well. The DEWATS plants achieved 95-100% STH egg removals as compared to the 67 to 100% in the centralized wastewater treatment plants. This could be attributed to the difference in treatment processes. Among the different STHs, reduction in Ascaris spp eggs was significantly higher, irrespective of the type of treatment, which is attributed to the high relative density of the egg resulting in a higher settling velocity than the other STH eggs. Reduction or elimination of STH eggs through wastewater treatment is achieved by removing the eggs from the wastewater into the sludge. STH egg concentration in sludge is therefore mostly higher than in the wastewater. Sludge from Durban and Dakar after 60 days of drying under ambient environmental conditions contained very high concentration of viable STH eggs. Ascaris spp, hookworm, Trichuris spp, Taenia spp and Toxocara spp were the commonly recorded STH eggs, except for Dakar were Taenia spp and Toxocara spp were not detected in the sludge. STH egg concentrations were higher in Dakar than in Durban, with viable STH egg concentrations exceeding both the USEPA regulatory value (≤0.25 eggs/g TS) and the WHO guideline value (≤1 eggs/g TS). This variation in egg concentration could be attributed to the difference in prevalence and intensity of STH infections in the two study areas. Over a ten-month study period concentration of viable eggs in the sludge from Durban varied considerably, probably influenced by the environmental conditions. A decay rate of 0.0056 per day was calculated for egg die-off during drying. The rate of decay is low therefore drying alone cannot produce sludge meeting both local and international standards and guidelines for sludge reuse. Determination of STH infection risks due to exposure to wastewater and sludge either directly or indirectly is critical in the prevention of infection. Exposure to the effluents during wastewater irrigation is one major route of infection. STH egg concentrations in the final effluents from the centralized and DEWATS wastewater treatment plants were consistently higher than the WHO recommended guideline for unrestricted agricultural use (≤ 1 helminth egg/L), whereby the direct reuse of the effluents for agriculture was found to pose a higher risk than the WHO tolerable risk of infection (1 ×10-2 pppy) for farmers and consumers. Annually the use of effluents from the DEWATS plants poses the least risk of infection (1.9 ×10-2 (±2.4×10-4)), which is marginally higher than the WHO tolerable risk value. Well maintained DEWATS plants are more efficient in removing or reducing the concentration of STH eggs in wastewater and therefore pose the least risks of infection compared to centralized wastewater treatment plants. Consumers of vegetables from these farms are also at considerable risks of STH infections. Probabilistic assessment of the STH infection risks showed that farmers applying sludge from Durban and Dakar without adequate protective measures had risks of infections higher than the WHO tolerable risks figure (1×10-2 pppy). Based on the estimated risks of infection after decay, exposure to farm soil after 40-50 days of sludge application may reduce the risks of infection to levels lower the WHO tolerable risks value. However, this may not be practical due to the need for farmers to attend to their crops frequently. Incorporation of the decay of the eggs into the risks assessment also indicated that, using lettuce as a representative vegetable, harvesting of vegetables in Dakar could be done after 40 days of sludge application to reduce the risks of infection to the WHO tolerable value but in Durban harvesting after 30 days ensures that consumers are protected. Therefore, to protect both the farmers and consumers exposed to STH eggs through wastewater/sludge reuse in agriculture the implementation of the WHO multi-barrier approach to risk reduction is required. Risks of STH infections could be directly estimated using epidemiological approaches. By using this approach, the concept of STH infection risks for farmers using wastewater was assessed through direct measurements of the concentration of STHs both in wastewater used for irrigation and the farm soil, as well as the actual load of STHs ova in the stool of farmers and their family members. In Kumasi, Ghana, wastewater used for irrigation of vegetables and the farm soil contained high concentration of STH eggs. There was positive correlation between STH concentrations in the wastewater/soil and STH eggs load in stool of the exposed farmers. Stool analysis after 3 months, following deworming, showed a fast re-infection rate. Farmers exposed to the wastewater were three times more likely as compared to the control group of non-farmers to be infected with Ascaris spp (OR = 3.9, 95% CI, 1.15-13.86) and hookworm (OR = 3.07, 95% CI, 0.87-10.82). These risks of infection were higher in the rainy season than the dry season. This corresponds to a higher egg concentration in wastewater used for irrigation during this period. This indicates a relationship between STH infection and egg concertation in the environment. This study therefore contributes to the evidence-based conclusion that wastewater irrigation contributes to a higher incidence of STHs infection for farmers. In conclusion, this thesis therefore presents a new revised method that can be used to determine the STH egg concentration in different environmental samples. The development of this method also provides an opportunity to comparatively assess the STH egg reduction/removal efficiency of the more commonly used centralized wastewater treatment plants and DEWATS plants. The accurate quantification of viable STH eggs provide inputs for the probabilistic assessment of STH infection risks for different populations exposed to effluents from these two wastewater treatment approaches. This assessment of risks provides a public health perspective to the wastewater treatment. Additionally, it was concluded with the used of this method that drying of sludge for 60 days in Durban or Dakar does not produce sludge of good quality for agricultural application. This was confirmed by the estimates of STH infection risks determined using quantitative microbial risks assessment. This thesis therefore shows the importance of accurate quantification of STH eggs in the determination of infection risks either though QMRA or epidemiological approache
A study on the use of homoepathic preparations for the control of downy mildew on cabbage
(1995) Brammer, Ronel; Rijkenberg, F. H. J.
The purpose of this research was to evaluate the efficacy of a homeopathic remedy prepared from Peronospora parasitica in the treatment of downy mildew on cabbage seedlings by measuring the percentage leaf area infected. Four different homeopathic potencies were used. Three fungicidal and a water treatment serving as controls. Special attention was paid to curative and preventative functions.
Venoarterial modified ultrafiltration versus conventional arteriovenous modified ultrafiltration during cardiopulmonary bypass surgery
(2009) Mohanlall, Rakesh; Nemlander, Arto; Adam, Jamila Khatoon
INTRODUCTION: The role of modified ultrafiltration (MUF) in removing inflammatory mediators, reducing the need for homologous donor blood and decreasing pulmonary vascular resistance after cardiopulmonary bypass (CPB) has already been established. Different types of MUF systems evaluated illustrated that none of the MUF techniques adhered to the normal venous to arterial blood flow dynamics. OBJECTIVES: This experimental study compared a conventional arteriovenous modified ultrafiltration (AVMUF) system to a custom designed venoarterial modified ultrafiltration (VAMUF) system. This technique of VAMUF was designed to mimic the pro-grade flow pattern of the body and cardiopulmonary bypass circuit as compared to the conventional retrograde AVMUF systems. METHODS: Sixty patients that underwent MUF were divided into two groups, the AVMUF (n = 30) and the VAMUF (n=30) groups. Modified ultrafiltration was performed for a mean time of 12 minutes in both groups. In AVMUF blood was removed from the aorta, haemoconcentrated and infused into the right atrium (RA). In VAMUF blood flow was from the RA through a haemoconcentrator and re-infused into the aorta. RESULTS: There was no significant difference in any of the demographic variables, CPB or crossclamping time. Results showed significant difference in the ventilation times, with the VAMUF requiring a shorter ventilation time than the AVMUF group. Intensive care unit (ICU) stay, Hospital stay and discharge days were all significantly lower in the VAMUF group as well. The VAMUF also showed a lower percentage fluid balance than the AVMUF. The systolic and mean blood pressure was significantly higher after VAMUF with a decrease in heart rate, and central venous pressure (CVP). The VAMUF group showed a significantly greater decrease of Creatinine, serum lactacte and uric acid over time with no significant differences in oximetry. CONCLUSION: Results prove that VAMUF is more effective compared to the conventional AVMUF regarding the haemodynamics and clinical parameters of the patient and is more physiological with regards to blood flow dynamics. The VAMUF is, therefore, a more physiological technique than AVMUF.