Effect of fire on characteristics of dissolved organic matter in forested catchments in the Mediterranean biome: A review.

Fires in forested catchments pose a water contamination risk from fire-derived dissolved organic matter (DOM). Fire events are expected to increase under a projection of warmer and drier climatic conditions; therefore, understanding the consequences of fire-derived DOM is critical for water supply and management of drinking water and catchments. This paper addresses how fire regime - the intensity, severity and frequency of fires - influences DOM quantity and composition in surface waters in forested catchments, and how long it takes for water quality to recover to pre-fire levels. A review of post-fire studies in Mediterranean regions reporting on DOM related parameters has been conducted. The literature shows that post-fire DOM composition and reactivity is different from DOM generated under processes of biological degradation, and hence our reliance on DOM 'bulk properties' and surrogate DOM bulk parameters may not provide sufficient information to deal with the potential complexity of the organic compounds produced by a catchment fire. Appropriate measures are important to adequately operate conventional water treatment facilities, for example. Critical parameters for the effects of burning include the alteration of DOM composition, aromaticity, and the relative amounts of labile/recalcitrant organic components. The literature shows mixed information for the influence of both burn severity and fire intensity, on these parameters, which indicates DOM response to fire is highly variable. For fire frequency, the evidence is more unequivocal, indicating that frequent fires change the composition of DOM to components that are less bioavailable, and elevate the degree of aromaticity, which may be detrimental to water quality. In addition, and in general terms, the more recent the fire, the more aromatic and humified DOM components are found, and vice versa. The recovery of surface water quality to pre-fire conditions was variable, with no safe temporal thresholds suggested in the literature. In some cases, fire-induced changes in DOM composition were observable up to 16 years post-fire. The lack of clearly observed trends in post-fire DOM with fire regimes could be attributed to numerous factors such as limited long-term and event-based observations, experimental design challenges, and site-specific biological, physical and hydrological factors. The application of terminologies used to describe fire regimes such as burn severity and fire intensity also creates challenges in comparing the outcomes and results from numerous studies.

Paediatric periorbital cellulitis: A 10-year retrospective case series review.

AIM: To identify the predictors of poor outcome and need for surgical management in paediatric patients with periorbital cellulitis. To assess the adherence to local guidelines in the management of periorbital cellulitis. METHODS: Retrospective descriptive analysis of clinical, laboratory and radiological characteristics of 175 paediatric periorbital cellulitis presentations at a UK teaching hospital over a 10-year period. Regression investigated correlations for continuous and categorical variables. RESULTS: A total of 175 paediatric presentations were diagnosed as periorbital infections over the 10-year period. Of these, 139 had pre-septal cellulitis, 27 had a subperiosteal abscess, 6 had an orbital cellulitis, 1 had an orbital abscess, 1 a cavernous sinus thrombosis and 1 an extradural abscess. Median age at presentation was 5 years (range: 1 month-17 years). In total, 169 (97%) cases received systemic antimicrobial treatment. Cross-sectional imaging occurred in 30% of cases and 18% required surgical intervention. Increasing C-reactive protein was associated with greater risk of post-septal disease and requiring surgery. The best predictors of post-septal disease in the multivariate analysis (R2 = 0.49, P = ≤0.001) were ophthalmoplegia (P = 0.009), proptosis (P = 0.016) and pain on eye movement (P = 0.046). Proptosis was the single most significant predictor of surgical management (R2 = 0.53, P = <0.001). CONCLUSION: Multidisciplinary involvement and early medical management can improve outcomes for most patients. Those who deteriorate despite medical management should be considered for prompt imaging and surgical management to avoid serious life-threatening or sight-threatening complications.

Automatic nystagmus detection and quantification in long-term continuous eye-movement data.

Symptoms of dizziness or imbalance are frequently reported by people over 65. Dizziness is usually episodic and can have many causes, making diagnosis problematic. When it is due to inner-ear malfunctions, it is usually accompanied by abnormal eye-movements called nystagmus. The CAVA (Continuous Ambulatory Vestibular Assessment) device has been developed to provide continuous monitoring of eye-movements to gain insight into the physiological parameters present during a dizziness attack. In this paper, we describe novel algorithms for detecting short periods of artificially induced nystagmus from the long-term eye movement data collected by the CAVA device. In a blinded trial involving 17 healthy subjects, each participant induced nystagmus artificially on up to eight occasions by watching a short video on a VR headset. Our algorithms detected these short periods with an accuracy of 98.77%. Additionally, data relating to vestibular induced nystagmus was collected, analysed and then compared to a conventional technique for assessing nystagmus during caloric testing. The results show that a range of nystagmus can be identified and quantified using computational methods applied to long-term eye-movement data captured by the CAVA device.

Cryptosporidium species and subtypes in animals inhabiting drinking water catchments in three states across Australia.

As part of long-term monitoring of Cryptosporidium in water catchments serving Western Australia, New South Wales (Sydney) and Queensland, Australia, we characterised Cryptosporidium in a total of 5774 faecal samples from 17 known host species and 7 unknown bird samples, in 11 water catchment areas over a period of 30 months (July 2013 to December 2015). All samples were initially screened for Cryptosporidium spp. at the 18S rRNA locus using a quantitative PCR (qPCR). Positives samples were then typed by sequence analysis of an 825 bp fragment of the 18S gene and subtyped at the glycoprotein 60 (gp60) locus (832 bp). The overall prevalence of Cryptosporidium across the various hosts sampled was 18.3% (1054/5774; 95% CI, 17.3-19.3). Of these, 873 samples produced clean Sanger sequencing chromatograms, and the remaining 181 samples, which initially produced chromatograms suggesting the presence of multiple different sequences, were re-analysed by Next- Generation Sequencing (NGS) to resolve the presence of Cryptosporidium and the species composition of potential mixed infections. The overall prevalence of confirmed mixed infection was 1.7% (98/5774), and in the remaining 83 samples, NGS only detected one species of Cryptosporidium. Of the 17 Cryptosporidium species and four genotypes detected (Sanger sequencing combined with NGS), 13 are capable of infecting humans; C. parvum, C. hominis, C. ubiquitum, C. cuniculus, C. meleagridis, C. canis, C. felis, C. muris, C. suis, C. scrofarum, C. bovis, C. erinacei and C. fayeri. Oocyst numbers per gram of faeces (g-1) were also determined using qPCR, with medians varying from 6021-61,064 across the three states. The significant findings were the detection of C. hominis in cattle and kangaroo faeces and the high prevalence of C. parvum in cattle. In addition, two novel C. fayeri subtypes (IVaA11G3T1 and IVgA10G1T1R1) and one novel C. meleagridis subtype (IIIeA18G2R1) were identified. This is also the first report of C. erinacei in Australia. Future work to monitor the prevalence of Cryptosporidium species and subtypes in animals in these catchments is warranted.

Profiling the diversity of Cryptosporidium species and genotypes in wastewater treatment plants in Australia using next generation sequencing.

Wastewater recycling is an increasingly popular option in worldwide to reduce pressure on water supplies due to population growth and climate change. Cryptosporidium spp. are among the most common parasites found in wastewater and understanding the prevalence of human-infectious species is essential for accurate quantitative microbial risk assessment (QMRA) and cost-effective management of wastewater. The present study conducted next generation sequencing (NGS) to determine the prevalence and diversity of Cryptosporidium species in 730 raw influent samples from 25 Australian wastewater treatment plants (WWTPs) across three states: New South Wales (NSW), Queensland (QLD) and Western Australia (WA), between 2014 and 2015. All samples were screened for the presence of Cryptosporidium at the 18S rRNA (18S) locus using quantitative PCR (qPCR), oocyst numbers were determined directly from the qPCR data using DNA standards calibrated by droplet digital PCR, and positives were characterized using NGS of 18S amplicons. Positives were also screened using C. parvum and C. hominis specific qPCRs. The overall Cryptosporidium prevalence was 11.4% (83/730): 14.3% (3/21) in NSW; 10.8% (51/470) in QLD; and 12.1% (29/239) in WA. A total of 17 Cryptosporidium species and six genotypes were detected by NGS. In NSW, C. hominis and Cryptosporidium rat genotype III were the most prevalent species (9.5% each). In QLD, C. galli, C. muris and C. parvum were the three most prevalent species (7.7%, 5.7%, and 4.5%, respectively), while in WA, C. meleagridis was the most prevalent species (6.3%). The oocyst load/Litre ranged from 70 to 18,055 oocysts/L (overall mean of 3426 oocysts/L: 4746 oocysts/L in NSW; 3578 oocysts/L in QLD; and 3292 oocysts/L in WA). NGS-based profiling demonstrated that Cryptosporidium is prevalent in the raw influent across Australia and revealed a large diversity of Cryptosporidium species and genotypes, which indicates the potential contribution of livestock, wildlife and birds to wastewater contamination.

Novel Primer Sets for Next Generation Sequencing-Based Analyses of Water Quality.

Next generation sequencing (NGS) has rapidly become an invaluable tool for the detection, identification and relative quantification of environmental microorganisms. Here, we demonstrate two new 16S rDNA primer sets, which are compatible with NGS approaches and are primarily for use in water quality studies. Compared to 16S rRNA gene based universal primers, in silico and experimental analyses demonstrated that the new primers showed increased specificity for the Cyanobacteria and Proteobacteria phyla, allowing increased sensitivity for the detection, identification and relative quantification of toxic bloom-forming microalgae, microbial water quality bioindicators and common pathogens. Significantly, Cyanobacterial and Proteobacterial sequences accounted for ca. 95% of all sequences obtained within NGS runs (when compared to ca. 50% with standard universal NGS primers), providing higher sensitivity and greater phylogenetic resolution of key water quality microbial groups. The increased selectivity of the new primers allow the parallel sequencing of more samples through reduced sequence retrieval levels required to detect target groups, potentially reducing NGS costs by 50% but still guaranteeing optimal coverage and species discrimination.

Polyphasic identification of cyanobacterial isolates from Australia.

Reliable identification of cyanobacterial isolates has significant socio-economic implications as many bloom-forming species affect the aesthetics and safety of drinking water, through the production of taste and odour compounds or toxic metabolites. The limitations of morphological identification have promoted the application of molecular tools, and encouraged the adoption of combined (polyphasic) approaches that include both microscopy- and DNA-based analyses. In this context, the rapid expansion of available sequence data is expected to allow increasingly reliable identification of cyanobacteria, and ultimately resolve current discrepancies between the two approaches. In the present study morphological and molecular characterisations of cyanobacterial isolates (n = 39), collected from various freshwater sites in Australia, were compared. Sequences were obtained for the small ribosomal subunit RNA gene (16S rDNA) (n = 36), the DNA-dependent RNA polymerase gene (rpoC1) (n = 22), and the phycocyanin operon, with its intergenic spacer region (cpcBA-IGS) (n = 19). Phylogenetic analyses identified three cyanobacterial orders: the Chroococcales (n = 8), Oscillatoriales (n = 6), and Nostocales (n = 25). Interestingly, multiple novel genotypes were identified, with 22% of the strains (17/77) having <95% similarity to available sequences in GenBank. Morphological and molecular data were in agreement at the species level for only 26% of the isolates obtained (10/39), while agreement at the genus level was obtained for 31% (12/39). Confident identification of the remaining 44% of the strains (17/39) beyond the order level was not possible. The present study demonstrates that, despite the taxonomic revisions, and advances in molecular-, and bioinformatics-tools, the lack of reliable morphological features, culture-induced pleomorphism, and proportion of misidentified or poorly described sequences in GenBank, still represent significant factors, impeding the confident identification of cyanobacteria species.

Specific and quantitative detection and identification of Cryptosporidium hominis and C. parvum in clinical and environmental samples.

Cryptosporidium is an enteric protozoan parasite that is resistant to inactivation by commonly used drinking water disinfectants. Between 2004 and 2010, it was responsible for 60% of all waterborne protozoan parasitic outbreaks reported worldwide. Most sporadic infections in humans and almost all outbreaks are caused by Cryptosporidium parvum and Cryptosporidium hominis. We report the development and validation of a quantitative qPCR assay using minor groove binder (MGB)-probes targeting a unique Cryptosporidium specific protein-coding gene, that directly detects, quantitates and identifies C. hominis and C. parvum in environmental and faecal samples. An internal amplification control (IAC) was also developed and included in this assay. The qPCR assay was compared with an 18S nested PCR assay for sensitivity and specificity. The analytical sensitivity for the qPCR assay was 1 oocyst and 1-10 oocysts for the 18S assay. Evaluation of analytical specificity of the qPCR assay revealed no cross-reactions with other genera and detected all C. parvum and C. hominis isolates correctly. The diagnostic sensitivity and specificity of the qPCR was 100% compared to 96.9% and 98.4%, respectively for the 18S assay. The qPCR assay was also highly reproducible with RSD (relative standard deviation) values of 1.4-9.4%, when the assay was performed by four different technicians. When tested on water samples, the qPCR assay was more sensitive than the 18S assay, detecting positives in 37 of 138 water samples compared to 35 for the 18S locus. This qPCR assay should be a valuable tool for the detection and differentiation of C. hominis and C. parvum in both clinical and environmental samples.

Prevalence of Cryptosporidium species in recreational versus non-recreational water sources.

Cryptosporidiosis, caused by the protozoan parasite Cryptosporidium, represents the major public health concern of water utilities in developed nations due to its small size, resistance to disinfection and ability to be shed in large numbers in faeces. In Australia, recreational access is not allowed on direct supply sources, however, in Western Australia, limited recreational access to drinking water catchments has been allowed, although only in the outer catchment. Recreational activities within 2 km of the drinking water body is prohibited. The present study compared the amount, prevalence and species of Cryptosporidium in recreational versus non-recreational water catchments in the south west of Western Australia (WA). Recreational water catchments, which allowed swimming and camping had a higher prevalence of Cryptosporidium and the majority of samples were the human-associated C. hominis. Non-recreational catchments had a lower prevalence and all the samples genotyped were C. parvum. Risk analysis identified increasing population as strongly correlated with an increase in the prevalence of Cryptosporidium in recreational catchments. This suggests that recreational access to drinking water catchments is a serious public health risk and government policy limiting activities to the outer catchment should be supported.

The effect of transdermal glyceryl trinitrate on 24 h ambulatory blood pressure in acute/subacute stroke.

BACKGROUND: High blood pressure is a common complication in acute stroke and is associated with a poor outcome. Aims This study assesses the effects of transdermal glyceryl trinitrate on 24 h ambulatory blood pressure in patients with recent stroke. METHODS: One hundred and seven patients with acute ischaemic or haemorrhagic stroke were included. The patients had been enrolled in one of two trials of transdermal glyceryl trinitrate (5 mg daily) or placebo/control, and underwent 24 h ambulatory blood pressure monitoring (56 glyceryl trinitrate, 51 control). Ambulatory blood pressure data were analysed using area under the curve for the entire 24 h, and day and night periods. Nocturnal dipping was defined as a decline in systolic blood pressure >10%. Comparisons of blood pressure between groups were performed by analysis of covariance (ANCOVA) with adjustments for trial and baseline measure. RESULTS: In comparison with control, glyceryl trinitrate significantly lowered 24 h blood pressure (systolic blood pressure/diastolic blood pressure 9.4/4.8 mmHg, P < 0.001/0.001, n=104), daytime blood pressure (8.7/4.2, P < 0.001/ <0.001, n=103) and night-time blood pressure (6.9/1.7, P=0.008/0.458, n=86). Only 86 patients (glyceryl trinitrate 45, placebo/control 41) had sufficient night blood pressure measurements to assign dipping status; 28 were dippers (12 glyceryl trinitrate, 16 control) and 58 were nondippers (33 glyceryl trinitrate, 25 control); glyceryl trinitrate significantly lowered systolic but not diastolic blood pressure in both dippers and nondippers. Treatment with glyceryl trinitrate increased the daytime heart rate (4·8 beats/min) but not the night-time heart rate. Patients whose blood pressure did not dip at night had a worse functional outcome at three-months. CONCLUSIONS: Transdermal glyceryl trinitrate (5 mg) significantly lowered 24 h blood pressure by 9/5 mmHg (equivalent to a 6% reduction) in both dipping and nondipping patients with acute/subacute stroke. This reduction in blood pressure is clinically relevant and is unlikely to be excessive.

Investigation of Ig.G adsorption and the effect on electrochemical responses at titanium dioxide electrode.

The adsorption of Immunoglobulin G on a titanium dioxide (TiO(2)) electrode surface was investigated using (125)I radiolabeling and electrochemical impedance spectroscopy (EIS). (125)I radiolabeling was used to determine the extent of protein adsorption, while EIS was used to ascertain the effect of the adsorbed protein layer on the electrode double layer capacitance and electron transfer between the TiO(2) electrode and the electrolyte. The adsorbed amounts of Ig.G agreed well with previous results and showed approximately monolayer coverage. The amount of adsorbed protein increased when a positive potential was applied to the electrode, while the application of a negative potential resulted in a decrease. Exposure to solutions of Ig.G resulted in a decrease of the double layer capacitance (C) and an increase in the charge-transfer resistance (R(2)) at the electrode solution interface. As more Ig.G adsorbed onto the electrode surface, the extent of C and R(2) variation increased. These capacitance and charge-transfer resistance variations were attributed to the formation of a proteinaceous layer on the electrode surface during exposure.