Veterinary Science Collected Works - Research Publications
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ItemThe Effectiveness of Global Constructed Shallow Waterbody Design Guidelines to Limit Harmful Algal Blooms(AMER GEOPHYSICAL UNION, 2021-08)Abstract Constructed shallow waterbodies are often designed and built to limit harmful algal blooms in urban regions. Efforts to reduce algal bloom occurrence in these waterbodies have largely focused on waterbody design, catchment criteria and onsite engineering options. However, many constructed shallow waterbodies that comply with design guidelines still experience harmful algal blooms. Identifying the knowledge gaps in current guidelines and examining their recommended design criteria can improve their effectiveness to reduce algal outbreaks. Here, we reviewed 66 global guidelines and identified common design criteria. The use of a ‘one size fits all' empirical approach and dated literature are common issues associated with the design criteria recommended. Further, only approximately one third of the guidelines that were analyzed directly mentioned harmful algal bloom‐related design criteria. To test the validity of these design values in a real‐world setting, the suitability of design factors in limiting harmful algal blooms was assessed by analyzing 222 shallow waterbodies monitored over a 9 year period in southeastern Australia. The site analysis indicated that macrophyte area to surface area ratio, shoreline development index, and fetch are the three most influential single design factors associated with harmful algal bloom reduction. The analyses highlighted the ineffectiveness of the existing design criteria globally, with blooms occurring even though some waterbodies were designed in accordance with recommended parameters. The analysis suggested that understanding interactions between multiple design factors may be a useful approach, for example, when considering the macrophyte area to surface area ratio in combination with the shoreline development index.
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ItemSARS-CoV-2 known and unknowns, implications for the water sector and wastewater-based epidemiology to support national responses worldwide: early review of global experiences with the COVID-19 pandemic(IWA PUBLISHING, 2021-05)Abstract Wastewater surveillance of pathogens may be a useful tool to help determine whether clinical surveillance of disease is effective or inadequate due to under-reporting and under-detection. In addition, tracking of pathogen concentrations over time could potentially provide a measure of the effectiveness of public health control measures and the impact of the gradual relaxation of these controls. Analysis of wastewater using quantitative molecular methods offers a real-time measure of infections in the community, and thus is expected to provide a more sensitive and rapid indication of changes in infection rates before such effects become detectable by clinical health surveillance. Models may help to back-calculate wastewater prevalence to population prevalence or to correct pathogen counts for wastewater catchment-specific and temporal effects. They may also help to design the wastewater sampling strategy. This article provides a brief summary of the history of pathogen wastewater surveillance to help set the context for the SARS-CoV-2 wastewater-based epidemiology (WBE) programmes currently being undertaken globally.
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ItemDietary Uptake and Depuration Kinetics of Perfluorooctane Sulfonate, Perfluorooctanoic Acid, and Hexafluoropropylene Oxide Dimer Acid (GenX) in a Benthic Fish(Wiley, 2020-03)Per‐ and poly‐fluoroalkyl substances (PFAS) are ubiquitously distributed throughout aquatic environments and can bioaccumulate in organisms. We examined dietary uptake and depuration of a mixture of 3 PFAS: perfluorooctanoic acid (PFOA; C8HF15O2), perfluorooctane sulfonate (PFOS; C8HF17SO3), and hexafluoropropylene oxide dimer acid (HPFO‐DA; C6HF11O3; trade name GenX). Benthic fish (blue spot gobies, Pseudogobius sp.) were fed contaminated food (nominal dose 500 ng g–1) daily for a 21‐d uptake period, followed by a 42‐d depuration period. The compounds PFOA, linear‐PFOS (linear PFOS), and total PFOS (sum of linear and branched PFOS) were detected in freeze‐dried fish, whereas GenX was not, indicating either a lack of uptake or rapid elimination (<24 h). Depuration rates (d–1) were 0.150 (PFOA), 0.045 (linear‐PFOS), and 0.042 (linear+branched‐PFOS) with corresponding biological half‐lives of 5.9, 15, and 16 d, respectively. The PFOS isomers were eliminated differently, resulting in enrichment of linear‐PFOS (70–90%) throughout the depuration period. The present study is the first reported study of GenX dietary bioaccumulation potential in fish, and the first dietary study to investigate uptake and depuration of multiple PFASs simultaneously, allowing us to determine that whereas PFOA and PFOS accumulated as expected, GenX, administered in the same way, did not appear to bioaccumulate.
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ItemDetection of Helminth Ova in Wastewater Using Recombinase Polymerase Amplification Coupled to Lateral Flow Strips(MDPI, 2020-03)Ascaris lumbricoides is a major soil-transmitted helminth that is highly infective to humans. The ova of A. lumbricoides are able to survive wastewater treatment, thus making it an indicator organism for effective water treatment and sanitation. Hence, Ascaris ova must be removed from wastewater matrices for the safe use of recycled water. Current microscopic techniques for identification and enumeration of Ascaris ova are laborious and cumbersome. Polymerase chain reaction (PCR)-based techniques are sensitive and specific, however, major constraints lie in having to transport samples to a centralised laboratory, the requirement for sophisticated instrumentation and skilled personnel. To address this issue, a rapid, highly specific, sensitive, and affordable method for the detection of helminth ova was developed utilising recombinase polymerase amplification (RPA) coupled with lateral flow (LF) strips. In this study, Ascaris suum ova were used to demonstrate the potential use of the RPA-LF assay. The method was faster (< 30 min) with optimal temperature at 37 °C and greater sensitivity than PCR-based approaches with detection as low as 2 femtograms of DNA. Furthermore, ova from two different helminth genera were able to be detected as a multiplex assay using a single lateral flow strip, which could significantly reduce the time and the cost of helminth identification. The RPA-LF system represents an accurate, rapid, and cost-effective technology that could replace the existing detection methods, which are technically challenged and not ideal for on-site detection in wastewater treatment plants.
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ItemDistribution and conservation of known secondary metabolite biosynthesis gene clusters in the genomes of geographically diverse Microcystis aeruginosa strains(CSIRO PUBLISHING, 2020)The cyanobacterium Microcystis aeruginosa has been linked to toxic blooms worldwide. In addition to producing hepatotoxic microcystins, many strains are capable of synthesising a variety of biologically active compounds, including protease and phosphatase inhibitors, which may affect aquatic ecosystems and pose a risk to their use. This study explored the distribution, composition and conservation of known secondary metabolite (SM) biosynthesis gene clusters in the genomes of 27 M. aeruginosa strains isolated from six different Köppen–Geiger climates. Our analysis identified gene clusters with significant homology to nine SM biosynthesis gene clusters spanning four different compound classes: non-ribosomal peptides, hybrid polyketide–non-ribosomal peptides, cyanobactins and microviridins. The aeruginosin, microviridin, cyanopeptolin and microcystin biosynthesis gene clusters were the most frequently observed, but hybrid polyketide–non-ribosomal peptide biosynthesis clusters were the most common class overall. Although some biogeographic relationships were observed, taxonomic markers and geography were not reliable indicators of SM biosynthesis cluster distribution, possibly due to previous genetic deletions or horizontal gene transfer events. The only cyanotoxin biosynthesis gene cluster identified in our screening study was the microcystin synthetase (mcy) gene cluster, suggesting that the production of non-microcystin cyanotoxins by this taxon, such as anatoxin-a or paralytic shellfish poison analogues, is either absent or rare.