Continuous faecal pollution in source water is a global problem that is particularly debilitating to rural communities that are directly dependent on untreated source water for all their domestic and other purposes. The elevation of indicator bacteria levels (such as the faecal coliforms) in the water may pose a public health risk. This study reports the results of microbial monitoring of the Mhlathuze River over a 21-month period. Elevated levels of indicator micro-organisms (both faecal and total coliforms) and heterotrophic plate count bacteria were observed from March 1998 to November 1999. Surface water temperature and rainfall during this period appeared to be some of the factors affecting the increased bacterial counts. Bacteria isolated from the river included E. coli, Pseudomonas spp., Enterobacter spp. (detected frequently), Serratia spp., Klebsiella spp., and Aeromonas hydrophila (detected less frequently). This study generated some essential baseline information of the microbial population for a section of the river utilised for domestic, agricultural and industrial purposes.
The microbial quality (total and faecal coliform counts) and some physico-chemical parameters of the Mhlathuze River water source were monitored during March 2001 to November 2002 and compared to the previous study conducted during 1998-1999. The results showed that most of the physical and chemical values obtained were within the recommended limits specified in the South African Water Quality Guidelines. High concentrations of metal were detected in water samples from Felixton and the Richards Bay estuary. Water samples from the Mhlathuze Pumping Station and Felixton, which contained higher concentrations of total nitrogen and phosphate, possessed higher faecal coliform contamination than other sites. The total coliform counts of the Mhlathuze River in this study period were noted to be significantly higher than those in the 1998 to 1999 period. As observed in the previous study, Felixton continues to be the site with major faecal contamination. The resuscitation results indicated that the level of faecal contamination in the Mhlathuze catchment was higher than that measured using conventional methods. Therefore the real impact of this "viable but non-culturable" state of microorganisms in this water system requires urgent attention. Larger fluctuations in the trend of total and faecal coliform counts were observed in 2001. This phenomenon coincided with the major construction of the Mhlathuze pumping station. High water surface temperatures and rainfall figures might have also contributed to this observation. Evidence from our results strongly suggests that the use of faecal coliform bacteria as indicators should be expanded and more research is indicated to identify the impact of the "viable but non-culturable" (VBNC) state of pathogens in this environment.
Routine characterisation of activated sludge and identification of the filamentous population by microscopic and/or other non-culture dependent techniques can assist in diagnosing the aetiology of poor performance of wastewater treatment works (WWTWs). In South Africa, most facilities rely solely on physicochemical indicators, treating reactors as 'blackboxes', with the result that process adjustments are often delayed, to the detriment of the environment. This study was performed in order to gain insight into the filamentous population found in activated sludge in Cape Town WWTWs, to compare these with other global and local literature findings, and to build capacity in this science. Physicochemical and plant performance parameters, in terms of nutrient removal and settling, were obtained from routine operational data and assessed in conjunction with the microscopic analyses of activated sludge samples taken over a 6-month period. Hypotheses on the links between filament types and/or plant configurations and/or operational parameters were formulated using existing literature. In order of prevalence, the five most common dominant filament species in 96 activated sludge samples were: Eikelboom Type 0092, Eikelboom Type 1851, nocardioforms, Microthrix parvicella and Eikelboom Type 021N. In order to compile a statistically significant database, it is recommended that an extensive nationwide study is conducted to link filament types with plant configurations, operational parameters and geographical locations.
Poultry is a major source of protein in sub-Saharan Africa and many other lower-income regions. Newcastle disease virus (NCDV) comprises a significant threat toward poultry production. While NCDV vaccines are routinely used in developed countries, those used in sub-Saharan Africa are mostly imported and are not specific to locally circulating strains. Indeed, the lack of rapid, field-based NCDV detection and the absence of cost-effective production methods for pure, strain-specific vaccines hampers efficient poultry production throughout these regions. This remains a major problem for both subsistence and commercial farming.The aim for this study was firstly, to develop a field-based isothermal PCR assay for NCDV detection that employed a portable instrument and real-time data transfer application. Secondly,to use the nucleic acid sequence data obtained from field isolates to develop a protocol compatible with rapid emergency vaccine production for NCDV.To achieve this, the isothermal PCR detection assay was applied to field isolates from suspected NCDV outbreaks on commercial poultry farms in KwaZulu-Natal, South Africa, while for the vaccine development, the NCDV matrix gene of one of the isolates was sequenced and used to design primers for the recombinant cloning of this antigen into an adenoviral vector.This‘vaccine vector’ and a control adenoviral vector were each amplified in 293T cells and then used to infect both 293T cells as a production cell line and chicken embryo fibroblasts (CEF) as a preliminary model of the target host. Western blotting confirmed the successful expression of the V5epitopetagby the control vector in both cell lines, which established the compatibility of the adenovirus vector as an appropriate carrier of the target antigen. Mass spectrometry confirmed expression of the NCDV matrix protein by the vaccine vector in both cell lines. In conclusion, the improved turnaround time from detection to the production of the vaccine antigen was under6weeks.The approach described here provides a rapid and cost-effective protocol for both the pathogen detection on-site and the production of pure vaccine antigens specific to an emerging field strain of NCDV within lower-income regions.
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