Predictive Mapping of Transmission Risk of a Soil-Transmitted Helminth across East Africa: Findings from Community Prevalence Surveys

Background: Despite being identified as a major health concern and neglected tropical disease, Ascariasis, caused by Ascaris lumbricoides, a soil-transmitted helminth, ranks among the most common infections worldwide. Methods: Based on prevalence data from the community surveys across East Africa for 1975-2009, we used ecological niche modeling to summarize and predict the spatial distribution of A. lumbricoides’ transmission risk. Results: Projection of this model across East Africa identified 51.4% of the region as suitable for A. lumbricoides transmission, with least suitable areas in the Sahara and the Somali-Chalbi deserts. Partial area under the curve (AUC) tests based on independent data showed that our model predictions were better than random expectations in predicting infection risk of A. lumbricoides; the model successfully identified areas of high and low infection risk in Ethiopia and Eritrea. Conclusions: Although preliminary, this occurrence-environment mapping approach provides predictions that can guide education and mitigation efforts in the broader East African region

Improving correlation of wastewater SARS-CoV-2 gene copy numbers with COVID-19 public health cases using readily available biomarkers

The COVID-19 (coronavirus disease 2019) pandemic has highlighted the potential role that wastewater-based epidemiology can play in assessing aggregate community health. However, efforts to translate SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) gene copy numbers obtained from wastewater samples into meaningful community health indicators are nascent. In this study, SARS-CoV-2 nucleocapsid (N) genes (N1 and N2) were quantified weekly using reverse transcriptase droplet digital PCR from two municipal wastewater treatment plants for 6 months. Four biomarkers [ammonium, biological oxygen demand (BOD), creatinine and human mitochondrial gene NADH dehydrogenase subunit 5] were quantified and used to normalize SARS-CoV-2 gene copy numbers. These were correlated to daily new case data and 1-, 2- and 3-week cumulative case data. Over the course of the study, the strongest correlations were observed with a 1-day case data lag. However, early measurements were strongly correlated with a 5-day case data lag. This indicates that in the early stages of the pandemic, the wastewater samples may have indicated active COVID-19 cases before clinical indications. Mitochondrial and creatinine normalization methods showed the strongest correlations throughout the study, indicating that human-specific biomarkers were better at normalizing wastewater data than ammonium or BOD. Granger causality tests supported this observation and showed that gene copies in wastewater could be predictive of new cases in a sewershed

Evaluation of empirical models coupled with EUTROMOD for water quality prediction in Kansas reservoirs

Agricultural land use contributes high nutrient and sediment loads to nearby streams, lakes, and reservoirs, which can lead to excessive algal growth and increased siltation. Future intensification of agricultural production could further aggravate water quality concerns. To objectively evaluate the effects of agricultural intensification on future water quality, modeling tools must be able to quantitatively predict the degree to which land use change will affect the trophic state of water bodies. This study evaluated the water quality model EUTROMOD as well as several national and regional in-lake empirical water quality models as predictive tools for analyzing and estimating water quality in 28 Kansas reservoirs of varying size and watershed land use. Model-predicted nutrient loading was used with several in-lake empirical models to predict values for total nitrogen (TN), total phosphorus (TP), and chlorophyll a concentrations. Predicted values were then compared to long-term water quality measurements obtained from the Kansas lake and reservoir monitoring program. All models over-predicted concentrations of TN and TP in Kansas reservoirs; however, predictions from the Bachmann TN and Canfield-Bachmann TP in-lake empirical models were most closely coupled to observed trends and had the least error. Two possible sources of model bias were identified: the sedimentation coefficient in the in-lake empirical models and the nutrient loading estimates from the watershed model. Areas of further research are suggested for determining the dominant source of model bias and improving quantitative predictions of water quality in the Midwest, USA

Differential fate of erythromycin and beta-lactam resistance genes from swine lagoon waste under different aquatic conditions

The attenuation and fate of erythromycin-resistance-methylase (erm) and extendedspectrum beta-lactamse (bla) genes were quantified over time in aquatic systems by adding 20-L swine waste to 11,300-L outdoor mesocosms that simulated receiving water conditions below intensive agricultural operations. The units were prepared with two different light-exposure scenarios and included artificial substrates to assess gene movement into biofilms. Of eleven genes tested, only erm(B), erm(F), blaSHV and blaTEM were found in sufficient quantity for monitoring. The genes disappeared rapidly from the water column and first-order water-column disappearance coefficients were calculated. However, detected gene levels became elevated in the biofilms within 2 days, but then disappeared overtime. Differences were observed between sunlight and dark treatments and among individual genes, suggesting that ecological and gene-specific factors play roles in the fate of these genes after release into the environment. Ultimately, this information will aid in generating better predictive models for gene fate

Accumulation of tetracycline resistance genes in aquatic biofilms due to periodic waste loadings from swine lagoons

Antibiotic resistance genes (ARGs) are emerging contaminants found in the water and sediments surrounding animal feedlots. In this study, the fate of five tetra cycline-resistance and 16S-rRNA genes released in swine waste were monitored for 21 days in the water column and biofilms in 12 mesocosms mimicking different natural receiving water bodies. Four treatments were employed in triplicate: two light exposures (light/dark) and two loading scenarios (single/periodic). As seen previously, light exposure had a significant effect on disappearance rates of tet genes in both the water column and biofilms, although absolute rates were significantly lower in the biofilms. Further, periodic versus single loading events resulted in >2 orders of magnitude higher tet gene levels in associated tanks. Regardless of treatment ARGs migrated quickly to biofilms, with 3% and >85% of detected tet determinants found in biofilms on days 1 and 4, respectively. Overall, these are the first quantitative data on specific ARG disappearance rates in biofilms, and also the first evidence of progressively accumulating ARG levels in biofilms under loading conditions typical of natural receiving waters. In summary, ARGs migrate rapidly to biofilms where they persist longer than adjacent waters, which suggests biofilms likely act as reservoirs for ARGs in nature

Access and participation in the community: a prospective qualitative study of driving post-stroke

PURPOSE: Loss of role as a driver significantly affects community participation; therefore, we aimed to explore the impact of driving issues post-stroke in community-dwelling stroke survivors. METHODS: A longitudinal qualitative study of community-dwelling stroke survivors, using semi-structured interviews. RESULTS: Twenty-two participants took part in 84 interviews over a 1-year period post-stroke. The majority of participants was independent and experienced few major depressive symptoms. ages ranged from 50 to 92 years. Emergent key themes included impact on quality of life, personal impacts, change to role performance and knowledge. Participants received inconsistent advice regarding return to driving. Confidence and availability determined public transport use. CONCLUSIONS: Driving advice should be standard practice prior to discharge. Allied health professionals can play an essential role in interventions addressing community participation, driver re-training and alternative transport use. Therapists have an important role in assisting stroke survivors to work through feelings of loss and in providing education concerning new skills to support this life transition

Bilateral osteomyelitis and liver abscess caused by hypervirulent Klebsiella pneumoniae- a rare clinical manifestation (case report)

Abstract Background Hypervirulent strains of Klebsiella pneumoniae are a recognized cause of a distinct invasive syndrome that results in pyogenic liver abscesses and metastatic complications, particularly in the Asia Pacific region. Reports of hypervirulent K.pneumoniae in Europe, the Americas and Australia indicate worldwide spread. We present a case of multi-focal osteomyelitis, a rarely described complication of hypervirulent K.pneumoniae in the medical literature. The prevalence of this condition in countries outside Asia may be expected to rise with increasing travel. Case presentation A 20-year-old Chinese man residing in Australia for 2 years presented with a 2-week history of gradually worsening leg pain preceded by 2 weeks of constitutional symptoms. Imaging with computerized axial tomography (CT) and other modalities revealed bilateral tibial lesions described as lattice-like linear lucencies involving the cortices with scalloping of the outer involved cortex. Cultures of tissue from a left tibial bone biopsy were positive cultures for K.pneumoniae. Whole-genome sequencing identified the isolate as K1 serotype ST23, a well-recognized hyper virulent strain capable of causing invasive disease. An abdominal CT revealed a 27x22mm liver abscess. The patient had no other metastatic manifestations of the disease, and responded to 6 weeks of intravenous ceftriaxone followed by 3 months of oral Ciprofloxacin. Conclusions Increased awareness of the manifestations and subsequent management of hyper virulent strains of K.pneumoniae by clinicians is important to assist early recognition and help minimize serious sequelae. Cases with overseas links, such as previous residence in the Asia Pacific area, are at higher risk for infection with the hyper virulent strain. This case highlights the need for clinicians to be able to recognize this important disease, especially in patients with the right epidemiological links, and to investigate and treat appropriately to prevent severe metastatic complications

Enhancing bioflocculation in high-rate activated sludge improves effluent quality yet increases sensitivity to surface overflow rate

High-rate activated sludge (HRAS) relies on good bioflocculation and subsequent solid-liquid separation to maximize the capture of organics. However, full-scale applications often suffer from poor and unpredictable effluent suspended solids (ESS). While the biological aspects of bioflocculation are thoroughly investigated, the effects of fines (settling velocity < 0.6 m3/m2/h), shear and surface overflow rate (SOR) are unclear. This work tackled the impact of fines, shear, and SOR on the ESS in absence of settleable influent solids. This was assessed on a full-scale HRAS step-feed (SF) and pilot-scale HRAS contact-stabilization (CS) configuration using batch settling tests, controlled clarifier experiments, and continuous operation of reactors. Fines contributed up to 25% of the ESS in the full-scale SF configuration. ESS decreased up to 30 mg TSS/L when bioflocculation was enhanced with the CS configuration. The feast-famine regime applied in CS promoted the production of highquality extracellular polymeric substances (EPS). However, this resulted in a narrow and unfavorable settling velocity distribution, with 50% +/- 5% of the sludge mass settling between 0.6 and 1.5 m3/m2/h, thus increasing sensitivity towards SOR changes. A low shear environment (20 s-1) before the clarifier for at least one min was enough to ensure the best possible settling velocity distribution, regardless of prior shear conditions. Overall, this paper provides a more complete view on the drivers of ESS in HRAS systems, creating the foundation for the design of effective HRAS clarifiers. Tangible recommendations are given on how to manage fines and establish the optimal settling velocity of the sludge

Enhancing bioflocculation in high-rate activated sludge improves effluent quality yet increases sensitivity to surface overflow rate

High-rate activated sludge (HRAS) relies on good bioflocculation and subsequent solid-liquid separation to maximize the capture of organics. However, full-scale applications often suffer from poor and unpredictable effluent suspended solids (ESS). While the biological aspects of bioflocculation are thoroughly investigated, the effects of fines (settling velocity < 0.6 m3/m2/h), shear and surface overflow rate (SOR) are unclear. This work tackled the impact of fines, shear, and SOR on the ESS in absence of settleable influent solids. This was assessed on a full-scale HRAS step-feed (SF) and pilot-scale HRAS contact-stabilization (CS) configuration using batch settling tests, controlled clarifier experiments, and continuous operation of reactors. Fines contributed up to 25% of the ESS in the full-scale SF configuration. ESS decreased up to 30 mg TSS/L when bioflocculation was enhanced with the CS configuration. The feast-famine regime applied in CS promoted the production of highquality extracellular polymeric substances (EPS). However, this resulted in a narrow and unfavorable settling velocity distribution, with 50% +/- 5% of the sludge mass settling between 0.6 and 1.5 m3/m2/h, thus increasing sensitivity towards SOR changes. A low shear environment (20 s-1) before the clarifier for at least one min was enough to ensure the best possible settling velocity distribution, regardless of prior shear conditions. Overall, this paper provides a more complete view on the drivers of ESS in HRAS systems, creating the foundation for the design of effective HRAS clarifiers. Tangible recommendations are given on how to manage fines and establish the optimal settling velocity of the sludge