Influenza vaccine uptake in Tunisia from two high-risk groups' perception and attitudes: a qualitative study.

Background: Pregnant women (PW) and older adult with chronic diseases (ECD) are priority groups for the influenza vaccination. This study was designed to have a better insight into the influenza perceptions and barriers of the vaccine uptake from these groups' perspectives. Methods: This qualitative study consisted of 20 focus group discussions (FGDs) enrolled from five governorates across the country (north, center, and south) between March 18 and July 10, 2019, in urban and rural areas. FGDs were conducted in Arabic (Tunisian dialect) and following the topic guide. Data were transcribed in the local language then translated into English and analyzed using Nvivo12 Software. This permitted the analysis thematic approach, using codes determined by the focus groups. Results: A total of 170 individuals participated in the FGDs (84 ECD and 86 PW). Both groups recognized the weakness of the immune system as key determinant for severity. While PW raised the lack of information about the vaccine, the ECD emphasized accessibility problems. Five main barriers to influenza vaccination were identified: cultural barriers and use of traditional medicine, misleading or lack of information about influenza and the vaccine, advice against its uptake, problems of availability and accessibility of the vaccine as well as mistrust towards the vaccine including adverse effects, vaccine composition and effectiveness. Conclusion: The study provided refined information from the perspectives of users to orient the policies regarding the promotion of influenza vaccine by decision makers among these two high risk groups.

Molecular-Level Composition and Acute Toxicity of Photosolubilized Petrogenic Carbon.

To examine the molecular-level composition and acute toxicity per unit carbon of the petroleum-derived dissolved organic matter (DOMHC) produced via photo-oxidation, heavy and light oils were irradiated over seawater with simulated sunlight. Increases in dissolved organic carbon concentrations as a function of time were associated with changes in the DOMHC composition and acute toxicity per unit carbon. Parallel factor analysis showed that the fluorescent dissolved organic matter (FDOM) composition produced from the heavy oil became more blue-shifted over time, while the light oil produced a mixture of blue- and red-shifted components similar to FDOM signatures. Ultrahigh-resolution mass spectrometry reveals that the composition of the DOMHC produced from both heavy and light oils was initially relatively reduced, with low O/C. With time, the composition of the DOMHC produced from the heavy oil shifted to unsaturated, high-oxygen compounds, while that produced from the light oil comprised a range of high O/C aliphatic, unsaturated, and aromatic compounds. Microtox assays suggest that the DOMHC initially produced is the most toxic (62% inhibition); however, after 24 h, a rapid decrease in toxicity decreased linearly to 0% inhibition for the heavy DOMHC and 12% inhibition for the light DOMHC at extended exposure periods.

High abundances of the nuisance raphidophyte Gonyostomum semen in brown water lakes are associated with high concentrations of iron.

Algal blooms occur frequently in lakes and oceans and the causes and consequences of those are often studied. In this study, we focus on a less well known type of algal bloom by the freshwater raphidophyte Gonyostomum semen. This species' abundance and occurrence is increasing, especially in brown water lakes, the most abundant lake type in the boreal zone. The aim of the study was to investigate which environmental factors are associated with G. semen by statistical evaluation of field data of 95 Swedish lakes over five years. Although we found G. semen to be associated with dark waters it was, contrary to our expectations, mainly high concentrations of iron, and only to a lesser extent high TOC (total organic carbon) concentrations, that were associated with blooms of G. semen. In addition, high phosphorus concentrations and low pH also appear to facilitate G. semen blooms. We suggest that browning of lakes caused by increased iron concentrations may decrease net heterotrophy by fostering heavy algal blooms, i.e. the opposite to commonly assumed effects of increased DOM (dissolved organic matter).

Simultaneous consumption and production of fluorescent dissolved organic matter by lake bacterioplankton.

Recent evidence suggests a key role of bacterioplankton in shaping the composition of the dissolved organic matter (DOM) pool in aquatic systems, not only through consumption but also through production of specific compounds, but the latter process is still not well understood. We used a bioassay approach to assess the patterns in bacterial production and consumption of five fluorescent DOM pools in seven lakes and two streams in Southeastern Québec, Canada, and the links these patterns may have with key aspects of bacterial metabolism, DOM origin and nutrients availability. Total dissolved organic C declined by 3-15% during these incubations, whereas the specific DOM pools had very different dynamics: Two humic-like fractions accumulated in all incubations, with rates of production increasing as a function of bacterial growth efficiency, which itself increased with phosphorus concentrations. In contrast, two protein-like fractions and a third humic-like fraction either increased or declined over the course of the experiments. The net production or consumption of these pools appeared to be a function of the contribution of terrestrial C to bulk DOM (derived from δ(13) C of the DOM) and of total bacterial activity. Our results suggest that lake bacterioplankton play a dual role in DOM dynamics, as consumers and also producers, and that the interplay between DOM origin and nutrient availability appears to determine the net outcome of bacterial DOM processing, thus influencing the bulk DOM composition and its fate in these aquatic systems.