Theses and dissertations (Health Sciences)

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An assessment of the extent of mercury pollution of the Mngceweni stream, the Umgeni River and the Inanda Dam in Kwa Zulu-Natal
(2001) Barratt, Graham James; Combrink, Jane
The debate surrounding mercury pollution of the river system below Thor Chemicals in Kwa Zulu Natal, South Africa has been of concern to the people of the region for several years. No scientific assessment of Mercury pollution has been carried out to date, other then a study conducted by Johnston et al. (1991) in 1990 in an area restricted to within 5 kilometres of the plant. Due to elevated levels being detected directly below the plant, Johnston et al. (1991) have expressed concern that this could result in the mobilisation of Mercury into the ecosystem and possibly threaten the Ecology of the Inanda Dam which is located approximately 20 kilometres south of Thor Chemicals which is a major reservoir for Durban. Added to this, the community residing in the area has expressed a great deal of concern and the matter was taken up in parliament in 1998. These factors provide impetus for a follow up study to determine the extent of mercury transformation into the higher trophic levels in the area surrounding Thor Chemicals. In order to quantify the extent to which mercury has become mobilised in the ecosystem and to identify possible pathways of exposure to the community, samples of sediment, algae, cattle hair and fish were taken at ten sample sites. These sample sites were selected at intervals along the Mngceweni and Umgeni River. The first sampling site was situated below Thor and the final sample site was located at the head of the Inanda Dam. Sediment, algae, cattle hair and fish were specifically chosen as they are considered to be reliable indicators of mercury pollution and mobilization. Fish,form an important part of the diet of the community residing in the study area. Mercury concentrations for the above parameters, were compared to mercury concentrations found in the control area, upstream from Thor, as well as to international and local standards. Composite sediment samples taken at the first sample site, within 500 metres of Thor Chemicals, revealed a mercury level of 54j.lg/gram. Mercury concentrations detected in the remainder of the composite sediment samples were significantly lower and revealed similar levels of magnitude throughout the rest of the study area. The higher concentration of mercury in the sediment at the site directly below Thor Chemicals may be attributed to a high
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.
A double-blind placebo controlled homoeopathic proving of Malus domestica 30CH, with a subsequent comparison of proving symptomatology to homoeopathic remedies of repertorial similarity
(2015) Moonsamy, Brenton Ricardo; Maharaj, Madhueshwaree; Somaru, Nevorndutt
Introduction The purpose of this investigation was to determine the effects of Malus domestica 30CH on a group of healthy provers and to compare these signs and symptoms to remedies of repertorial similarity. Malus domestica (common domestic apple) is an indigenous South African fruit which grows on the Drakensberg Mountains in Northern KwaZulu-Natal and is a regular part of the diet for those living there. This study hypothesized that Malus domestica 30CH would prove observable signs and symptoms in healthy individuals. Further it was hypothesized that the comparison of Malus domestica to remedies of reportorial similarity would highlight similarities and differences between existing homoeopathic remedies and Malus domestica 30CH thereby clarifying the therapeutic action of this new remedy and its relative location in the materia medica. The study was conducted by two researchers who each managed 15 provers and shared all primary data. The second researcher hypothesized that there would be a similarity between the proving symptoms of the remedy and the Doctrine of Signatures of the original substance (Ramnarayan 2014). Methodology A double blind placebo controlled proving of Malus domestica 30CH was conducted on 30 healthy volunteers who met specific inclusion criteria, with 6 receiving placebo and 24 receiving verum. A case history and thorough physical examination was performed on every prover before commencement of the proving. Recording of the data collected was in the form of a journal. Once the proving was completed information from each prover was collated and assessed by the two researchers. The symptoms elicited were then translated into materia medica and repertory language and a complete homoeopathic picture of the remedy appeared. Information from case histories and physical examinations were also considered. A repertorisation of 10 rubrics chosen to represent the essence of Malus domestica was conducted using Radar Opus software. Exclusion repertorization then followed in order to identify those remedies producing the highest numerical value and total number of rubrics within the animal, mineral and plant kingdoms in particular. Results Vast arrays of symptoms were experienced by the provers. Polarities in the symptoms were often displayed. On the emotional plane, there were symptoms of depression, sadness and cheerfulness. Some provers experienced tranquility and others felt anger, frustration and irritation. On the mental plane there were symptoms of clarity, focused concentration and confusion. The presence of delusions was marked. The most prominent delusion which infiltrated the mental and physical plane was of disconnection and separation. The main symptoms were sensations as if the extremities were separated from other areas. There was cramping and itching of the extremities as well. Pulsating headaches with perspiration of the scalp and eye pain were experienced. Various gastrointestinal symptoms were experienced ranging from distention, eructations, cramping, and diarrhea to hemorrhage after stool. Constriction of the chest and a loose, dry cough was also experienced. Cervical and lumbar back pain was reported. Sleep was described as unrefreshing with sleeplessness. The themes that emerged from the dreams were of danger (including danger to family), banquets, parties and helping others. The provers had a craving for tea. The similar remedies that emerged from the repertorial analysis were; Natrum muriaticum, Rhus toxicodendron, Lyssin, Cinchona officinalis and Pulsatilla pratensis. Conclusion The proving of Malus domestica 30CH did produce well defined symptoms that were clearly observed in healthy provers as proposed by the hypothesis. As hypothesized the comparison of Malus domestica to remedies of repertorial similarity did highlight similarities and differences between existing homoeopathic remedies and Malus domestica 30CH thereby clarifying the therapeutic range of this new remedy and its relative location in the materia medica.
The effect of Phosphoricum acidum 200CH on the adverse physiological effects induced by exercise in cyclists
(2011) Pantalone, Giovanni; Botha, Izel
The treatment with homoeopathic remedies, namely Phosphoricum acidum 200CH has proved to be effective in many clinical situations; however confirmation of its use within the sporting industry is limited. This study aimed to test Phosphoricum acidum 200CH efficacy in treating highly trained cyclists. This study was a superiority trial, in which the homoeopathic intervention was hypothesized to be superior to the placebo control group, in a statistically significant way (p < 0.05). Aim This study aimed to test the use of Phosphoricum acidum 200CH in treating the adverse physiological and psychological symptoms induced by exercise on cyclists. The aim for treating these adverse symptoms, induced by exercise, is to enhance performance and recovery of cyclists. Performance and recovery were tracked by assessing blood lactate concentration, oxygen consumption rate, heart rate, peak power output and emotional status. Methodology The study was a randomized controlled clinical trial, parallel group design. Participants were selected using convenience sampling of male road and mountain bike cyclists in the Western Cape. This study followed an explanatory Randomized Controlled Trial test, where the efficacy of the homoeopathic remedy (Phosphoricum acidum 200CH) was under investigation. The participants were selected with great care and testing was completed under highly controlled conditions. Thirty competitive male cyclists volunteered for this study. All participants were required to complete two cycling power to exhaustion interval tests, consisting of a ten minute warm-up at 100 Watts, followed by a five minute constant load at 150 Watts. The purpose of the constant load was to test cycling economy (CE). Thereafter the workload was increased to 200 W for 30 seconds and then the workload was increased by 20 Watts every 30 seconds. The test continued until the participant could no longer maintain the set repetitions per minute for that workload. The peak power output attained iv was recorded. The first test served as a baseline, after which a single dose of Phosphoricum acidum 200CH or identical placebo was administered, a 30 minute recovery period allowed for the remedy to take effect. The test interval was then repeated, the second test results were then compared to the first baseline test to determine the effect of treatment. The study took many different aspects of the remedies action on the cyclists into account, including mental and physiological effects. Breath-by-breath gases were continuously recorded. Expired gases, volumes and air flow were sampled through a flow meter and gas sampling line and heart rate was measured through telemetry (Polar®, Polar Electro, Oy, Finland) and analyzed by a cardio-pulmonary metabolic system (Quark CPET ® Cosmed, Rome, Italy, 2009). Data recorded was filtered for values outside the normal ranges and averaged for every five seconds. Oxygen consumption (vO2 mL.min-1) and heart rate (bpm) at different stages of each test interval were recorded. More specifically oxygen consumption and heart rates were averaged over the 5 minute section following the warm-up to determine cycling economy, directly after exhaustion for one minute and two minutes following exhaustion for another one minute period. Maximum attained heart rate was recorded for each interval test. Maximum oxygen consumption (vO2Max Absolute) was calculated as the mean of the highest three values attained, this mean was then divided by the participants body mass to determine maximum aerobic capacity (vO2Max Relative). Blood lactate levels were tested before, 15 minutes into and directly after each interval, to assess resting lactate status, cycling economy and to determine maximum lactate accumulation. Psychological testing included mood analysis, using a Stellenbosch mood scale (STEMS) questionnaire and further symptoms were analyzed using a Numerical rating scale (NRS) with symptomatic questions. Results From the results, it was clearly apparent that the control group proved to be of a higher calibre when comparing performance variables of the two groups namely:  Higher peak power output  Higher vO2Max  Lower economy lactate v  Lower resting lactate Despite the treatment group being the weaker of the two groups, they showed improvement in performance after administration of the remedy. This improvement was manifest through physiological alteration in the second test. More exclusively is the acceptance of the hypothesis concerning heart rate and oxygen consumption, whereby results showed that the administration of Phosphoricum acidum 200CH decreased heart rate and submaximal oxygen consumption rates during performance and recovery. There was no observable psychological effect during this study. The results suggest that Phosphoricum acidum 200CH primary demonstrated physiological effects on the cyclists. The researcher believes that this is due to insufficient time given for psychological alterations. Conclusion The Phosphoricum acidum 200CH has proven to be effective in enhancing cycling economy, reducing maximum heart rate and enhancing recovery to a large degree for the first minute following exhaustion. These positive effects are of great importance as the treatment group was the weaker of the two groups. Resulting in the possibility of even larger results being observable in repeated studies where both groups have similar performance abilities.
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.
Evaluation of selected South African medicinal plants in the treatment of pre-eclampsia
(2023-05) Reddy, Rebecca; Govender, Nalini; Naicker, Thajasvarie
Background: The growing prevalence of pre-eclampsia (PE) has been recognized as a serious global health threat being a key contributor to maternal and feotal morbidity and mortality. Locally, the effects of PE are multiplied due to strained public healthcare resources. The need for novel therapeutic strategies has gained significant importance, as conventional options may be inaccessible and costly to a large percentage of the population and are often associated with side effects. The scientific validation of alternative approaches, such as phytotherapy, has become a major focal point in the treatment and management of PE, as it is perceived to be cheap, accessible, and possess minimal side effects. Medicinal plants are a rich source of phytocompounds that display various biological activities. Hence, these plants have gained interest within the field of novel drug discovery and may offer potential therapeutic benefits in managing PE and its associated complications. Aim: This study aimed to determine the potential of applications of South African medicinal plants in the management of PE by investigating their anti-oxidative and angiotensin-converting enzyme (ACE) inhibitory activities. The plants used in this study were Artemisia afra, Clausena anisata, Dombeya rotundifolia, Rhus chirendensis, Sclerocarrya birrea and Warbugia salutaris, as well as phytocompounds 3β-taraxerol, β-amyrin, oleanolic acid, hesperidin, nicotinamide, and quercetin for the treatment of PE. We then explored the anti-hypertensive properties of hesperidin in a novel rodent model of PE as a potential treatment option. Methodology: The methanolic extracts of the selected plants and phytocompounds were initially evaluated in vitro for their antioxidant potential and ACE inhibition activities using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, the nitric oxide (NO) scavenging assay and the ACE inhibition assay, respectively. To investigate in vivo effect of the hesperidin, Sprague-Dawley rats were surgically implanted with mini-osmotic pumps to deliver arginine vasopressin (200 ng/h) subcutaneously to create a PE phenotype. Animals were treated with hesperidin (200mg/kg.b.w) via oral gavage for 14 days and the physiological effects were characterized by evaluating the clinical, biochemical, hematological, and foetal parameters across all experimental groups. Key findings: Of the medicinal plants and phytocompounds evaluated, Dombeya rotundifolia, hesperidin, and nicotinamide demonstrated significant ACE inhibitory and antioxidant activity, showing the best potential for management of PE related symptoms. Hesperidin administration alleviated the AVP-induced hypertension associated with PE development and improved maternal and foetal outcomes. Placental and individual pup weights were significantly increased in the pregnant hesperidin-treated groups. Urinary protein and urine creatine levels were also significantly improved following treatment with the phytocompound. In addition, hesperidin improved several biochemical and hematological markers including white blood cell counts and lymphocyte levels. Conclusion: Our findings suggest the potential of medicinal plants to ameliorate oxidative stress-associated disorders. Furthermore, hesperidin improves physiological outcomes in a novel AVP-induced rodent model and support its potential use in the treatment of PE. We provide significant physiological evidence for the use of hesperidin as an alternate anti-hypertensive agent, in resource-limited areas where conventional drugs are often costly and inaccessible. Moreover, we provide a workflow for evaluating other potential phytochemicals that may be valuable in the treatment of hypertensive disorders of pregnancy.
Formulation and in vitro analysis of essential oil blended (Cymbopogon citratus, Syzgium aromaticum and Melaleuca alternifolia) biocompatible hand sanitizer against common bacterial pathogens
(2024) Saunders, Cindy; Puri, Adarsh Kumar; Borg, Dorinda
ABSTRACT Essential oils (EOs) are predominantly known for their use in aromatherapy, cosmetic, food and pharmaceutical industries. Combination of EOs may result in holistic synergistic effects due to a blended biocompatible mixture. In this study, three EOs were selected out of the seven EOs tested for their efficacy against Gram-positive and Gram-negative bacteria based on the results of disc diffusion. The Minimum Bactericidal Concentration (MBC) of EOs from Cymbopogon citratus (lemongrass), Melaleuca alternifolia (tea tree) and Syzgium aromaticum (clove) were determined against Micrococcus luteus, Bacillus subtilis, Bacillus cereus, Klebsiella pneumoniae and Escherichia coli ATCC 11775. The EOs were analysed using gas chromatography mass spectrometry (GC-MS) to identify the volatile organic compounds. Geranial, neral, neryl acetate and β-caryophyllene were present in highest concentrations among 48 chemicals identified in lemon grass essential oil (LGEO). GC-MS identified 17 chemical compounds in clove EO (CEO) with eugenol, eugenol acetate and β-caryophyllene present in highest concentrations. A total of 52 compounds were identified with terpineol-4, γ-terpinene, α-terpipene and 1,8-cineole (eucalyptol) being the most prevalent compounds in tea tree EO (TTEO). Response surface methodology (RSM) using central composite design (CCD) was used to develop a mathematical model that determined the optimal concentrations of LGEO, TTEO and CEO as 0.10%, 0.11% and 0.10%, respectively. This investigation highlighted the importance of microbiological techniques and statistical optimization tools to study the synergistic effect of selected EOs towards developing a combined EO - based antibacterial treatment technology. Overall, this study showed the potential of developing a biocompatible hand sanitizer which resulted in marked log reduction of bacteria. Further study on the efficacy of the developed EO-mixture against viruses, fungi and nematodes will provide useful scientific knowledge.
An injury profile of musculoskeletal injuries in mountain bikers in the eThekwini Municipality
(2022-09-29) Van Eck, Rochelle; Varatharajullu, Desiree
Background: Mountain biking is a sport that appeals to men and women who enjoy an adrenalin rush. It is practised on any terrain classified as ‘off-road’ such as gravel roads, sugar cane fields, farmland, mountainous areas, and forests. It involves riding over rough and tricky terrain with a mountain bike and has become a global phenomenon among many athletes of all fitness levels. The popularity of this sport has grown as it is well known for its health benefits, family participation, recreational enjoyment, its ability to enhance overall fitness, and the fact that it offers those who are driven opportunities to be highly competitive. However, as is the case with any competitive and recreational sport, mountain bikers are prone to suffering a unique set of injuries. Mountain bikers want to recover and get back on their bikes as soon as possible, but there is a paucity of literature on the injury profile of mountain bikers in South Africa, hence recovery strategies may not always have the desired results. Aim: The aim of this study was to establish the injury profile of the musculoskeletal injuries that mountain bikers sustain, with special focus on those enthusiasts in the eThekwini municipality of KwaZulu-Natal, while the risk factors associated with this sport were also explored. Methodology: Participants were recruited at cycling clubs, after training sessions when they gathered in coffee shops, and individually at mountain bike parks. Before completing the questionnaire, each participant was required to read a letter of information and sign an informed consent form. Informed consent and post-pilot study questionnaires were completed, gathered, and deposited into separate sealed boxes. Each questionnaire was given a code for statistical analysis before data were captured on a spreadsheet. Results: A total of 175 questionnaires were received and the data were statistically analysed. The results revealed that not applying any preventative measures when training for this sport was the main causative factor of injuries among mountain bikers in the eThekwini Municipality. The majority of the injuries occurred in white males between the ages of 45 to 50 years and in participants who practised this sport for more than 12 hours a week. The most common areas of the body that sustained injuries were shoulders, legs, knees, and wrists, while the most common types of injuries were bruises, cuts, and sprains. The predominant mechanisms that caused these injuries were falls and contact with stationary objects. Conclusion: The findings that emerged from the data were consistent with the literature on mountain biking, but it must be mentioned that the injuries that were described related to earlier studies that had been conducted among either international mountain bikers or road cyclists. The current study’s findings are distinctive of the eThekwini Municipal area in KwaZulu-Natal, South Africa. Additional studies need to be conducted in other provinces of South Africa in order to create a more accurate injury profile associated with the mountain biking sport in this country.
An investigation to establish an injury profile in South African cyclists and its association to bicycle set-up
(2006) Mills, Barry-John
The first objective was to investigate the injury profiles of South African cyclists, especially those relating to mountain bicycle use on the road, as there appears to be no knowledge available on mountain bicycle use on the road and related injuries. Secondly, to see if there is an association between injuries and bicycle set-up in a South African context.
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
Preparedness of bridging programme graduate nurses to assume the role of a newly qualified professional nurse
(2023-05-31) Karapan, Selvum; Sokhela, Dudu Gloria; Pillay, Padmini; Coopasami, Marilynne
Preparedness of bridging programme graduate nurses to assume the role of a newly qualified professional nurse has been an area of debate between nurse educators and employers in a rapidly changing healthcare environment. Factors such as heavy workloads, staffing shortages and increased patient turnover, can prove to be stressful for the graduate nurse, resulting in a lack of confidence in their ability to effectively carry out their new role in the clinical setting. Purpose of the study The purpose of this study was to explore the preparedness of bridging programme graduate nurses to assume the role of a newly qualified professional nurse. Methodology A quantitative, descriptive survey research design was used for the study. The sample for the study was 95 bridging programme graduate nurses who had graduated from the Private Nursing Education Institution in the year 2020 and were working in the private hospital environment for not more than a year. Data was obtained through a questionnaire on KwikSurvey. Findings The study established that bridging programme graduate nurses that had more than five years of working experience as an enrolled nursing auxiliary and enrolled nurse, had significantly increased patient care and management competencies. While 52.50% (n=50), that had less than one year of experience as an enrolled nursing auxiliary and enrolled nurse significantly reduced their general nursing care activities and management competency. The study also noted that 61% of the respondents did not receive clinical support from the unit manager. This study concluded that graduate nurses that had less than one year of work experience as an enrolled nursing auxiliary and an enrolled nurse significantly lowered their competencies in general and patient care activities. In this study, it was found that the bridging program graduate nurses needed more mentorship and activities that would enhance their general and patient competency because the more mentors they had, the more competent they were. The study further highlighted several challenges during their transition as a newly qualified professional nurse such as shift leading after a month after graduating and having no mentors to guide them in decision making; hence in this study it was noted that newly qualified graduate nurses must be provided with the necessary clinical and managerial assistance to better support them for their new role hence preventing new nurses from experiencing transition shock during their initial stages of transition from a graduate nurse to that of a professional nurse.
The prevalence of musculoskeletal dysfunction in the upper quadrant and its relationship with mobile phone usage in a student population at a University of Technology
(2020-06-10) Durell, Jacques; Varatharajullu, Desiree
The aim of this study was to investigate mobile phone factors relating to demographics, anthropometry, usage and technique associated with those who were or were not experiencing upper quadrant musculoskeletal pain and dysfunction in a student populace. Subjects: A total of 384 participants selected from 21 909 registered students at the DUT spread over the six faculties, in order to reflect the accuracy of the total population and give a statistically significant result. The faculties included Accounting and Informatics, Applied Sciences, Arts and Design, Engineering and the Built Environment, Health Sciences and Management Sciences. This 378 was calculated by a biostatistician using a 95% confidence interval and 5% margin of error, from the total DUT population of 21 909 (Matthews 2017) (Appendix C). The total response rate was 384 which was six more than what was required as more questionnaires were distributed in order to account for short fall. All questionnaires were completed and analysed giving a response rate of 100%. Methodology: The measurement tool was a three-tiered questionnaire. The first section was demographics and anthropometric related questions, the second section was related to pain and dysfunction and the third section around the parameters of mobile phone usage and technique. After full approval and permission was granted by the Institutional Research Ethics Committee and the Durban University of Technology research office, students were either approached directly by the researcher or during a selected lecture period. Lecturers were contacted by the researcher directly to obtain permission. In requesting permission, it was pre-arranged that the first or last twenty minutes would be available on a certain lecture date, so as not to disrupt academic time if the lecturer concerned was agreeable to this. Two separate ballot boxes would be used to collect the informed consent forms and the questionnaires respectively in order to maintain confidentiality and anonymity. The participant’s name was not used on the data sheets. A code was allocated to each questionnaire. Results: In total, 384 questionnaires were completed and analysed. Participants who were experiencing current pain or discomfort totalled 37.2% (n=143) and those participants experiencing pain in more than one region was 23.2% (n=89). The most common prevalence of pain was lower thoracic pain and/or discomfort affecting 6.3% (n=24) of participants and a combination of regions was reported by 20.3% (n=78) of participants. The more specific locations of pain and/or discomfort were lower thoracic pain/discomfort reported in 16% (n=62), posterior neck pain in 12% (n=46), posterior left shoulder pain in 8.9% (n=34), posterior right shoulder pain in 7.6% (n=29) and the occipital region pain in 7.6% (n=29). The reason for location of lower thoracic pain/discomfort being higher than that of lower thoracic pain, was due to a combination factor of regional pain being reported by 20.3% (n=78) of participants, when reporting on the prevalence of pain. Participants experiencing no associated symptoms was 0.5% (n=2). Types of pain experienced that was reported in this study consisted of dull achy pain found in 2.6% (n=10) and sharp shooting pain consisted of 2.6% (n=10) of participants. Dysfunction reported was headaches in 4.4% (n=17) and stiffness in 2.9% (n=11) of participants. Pain intensity versus typing technique revealed a statistical significance between pain intensity and preferred typing technique (p=0.001). Conscious aggravation of pain and use vs demographics showed three statistically significant results occurring between years enrolled (p=0.014), hand dominance (p=0.039) and occupation (p=0.010) with respect to current aggravation by a mobile phone. Conscious aggravation of pain and use vs technique showed a statistical significance with respect to phone orientation (p=0.044). Conclusion: This studies prevalence may have decreased, but the incidence of pain and/or discomfort is consistent with the knowledge of previous studies conducted on the prevalence of musculoskeletal pain associated with mobile device usage. Though due to the uniqueness in design, one can now associate estimated factors and see that focus needs to be placed on an ergonomic approach (Hooper 2014) consisting of a holistic perspective with both phone user and work space environment factors. Dahl (2000) breaks down the biopsychosocial approach into factors of importance such as physical, cognitive, cultural, perceptual and sensing systems, biorhythms and disabilities, work experience, communication and vocational training, as well as health history and occupational stress. It would be best applied in conjunction with the use of chiropractic spinal manipulation, as well as manual therapeutic therapies and other modalities used by chiropractors that have been shown to be effective in the conservative treatment of conditions such as myofascial pain syndromes caused by myofascial trigger points, tendinopathies and chronic neck pain and especially in conjunction with exercise therapy (Pfefer 2001; Vernon and Schneider 2009)
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