Human Illness Research Articles

Mixed-Matrix Membrane-Based Piezoelectric CO2 Sensor with Self-Humidity Compensation.

Monitoring the CO2 concentration is crucial for assessing respiratory illnesses in humans and safeguarding the environment. The ongoing difficulty lies in achieving highly sensitive detection while also eliminating the interference caused by humidity. There is an unmet need for portable sensors with both high sensitivity and good moisture resistance to monitor CO2 in real time. In this study, a novel sensor capable of capturing the piezoelectric signals induced by CO2 gas is developed. A quartz crystal microbalance (QCM) coated with a mixed- matrix membrane of metal-organic framework (MOF)/polyether block amide (Pebax) is designed as a transducer to detect CO2 at room temperature. The change in the concentration of CO2 can be detected by the frequency shift of the QCM sensor. The sensor shows an ultrahigh sensitivity of 371.8 Hz to 1000 ppm of CO2 because of the abundant polar group and nitrogen Lewis basic groups. Furthermore, the implementation of a self-humidity compensation algorithm significantly enhances the accuracy and reliability of CO2 concentration monitoring by effectively addressing the issue of humidity interference. Our research underscores the immense potential of MOF/Pebax QCM sensors with self-humidity compensation ability in the field of CO2 gas monitoring.

Palmitoylethanolamide supplementation for human health: A state-of-the-art systematic review of Randomized Controlled Trials in patient populations.

Interest in preventative dietary interventions for human health has increasingly focused on the endocannabinoid (eCB)-like compound palmitoylethanolamide (PEA), a bioactive lipid mediator with anti-inflammatory, analgesic, and neuroprotective properties. This Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020-compliant systematic review aimed at collecting and comprehensively discussing all available data from Randomized Controlled Trials (RCTs) evaluating the efficacy and tolerability of PEA supplementation across human illnesses in patient populations. Overall, 48 eligible outputs from 47 RCTs were extracted, covering neuropsychiatric (n=15), neurological (n=17), somatic (n=13), and visceral (n=11) disturbances, as well as PEA effects on blood/plasma or other tissue biomarkers (n=10). The strongest evidence emerged from RCTs exploring PEA impact on pain management and measures of general wellbeing, especially in its ultramicronized/micronized or cold-water dispersible formulations, showing good tolerability compared to controls. Also, alongside symptom improvement, PEA demonstrated to modulate biomarkers early altered in the initial phases of an illness or contributing to its progression, suggesting a disease-modifying potential. This systematic review provided a comprehensive overview of the therapeutic potential of PEA across RCTs, highlighting its versatility either as monotherapy or add-on treatment for various clinical conditions.

Highly virulent colistin-susceptible Salmonella Havana ST1524 carrying the mcr-9.1 gene in food.

Salmonella enterica subsp. enterica serovar Havana is a potential pathogenic serotype that can cause human foodborne illness. Therefore, we have conducted a microbiological and genomic surveillance study of Salmonella Havana from food in Brazil. Strikingly, we identified a colistin-susceptible Salmonella Havana strain (NC_STy4) carrying the mcr-9 gene, in salted chicken breast. Genomic analysis revealed that Salmonella Havana strain belonged to the international sequence type (ST) ST1524, circulating at the human-animal-environmental interface. Although the resistome analysis confirmed the presence of mcr-9 and aac(6')-Iaa genes, as well as a parC (Thr57→Ser) mutation, this strain exhibited a pansuceptible phenotype. Noteworthy, Salmonella Havana NC_STy4 exhibited a highly virulent behavior, killing 100% of Galleria mellonella larvae at 13h post-infection. In this regard, invasins (invA, ibeB), non-fimbrial adherence (misL), fimbrial adherence (fimH), magnesium uptake (mgtB and mgtC), regulation (phoP, phoQ, and pipB), secretion system (ssaHJKLNOQRU), and translocated effector (sopB/sigD and sopE2) virulence genes were predicted. IncHI2 and IncHI2A plasmids were also identified. While these findings underscore the urgent need for surveillance and monitoring foodborne pathogens carrying a wide virulome, colistin-susceptible Salmonella isolates may be silent reservoirs of the mcr genes.

The Role of Stem Cell Therapies in the Treatment of Neurodegenerative Diseases.

Cellular replacement therapy and genetic transfer in injured brains provide new pathways for treating human neurological illnesses. Current progress in the field focuses on the production of neurons and glial cells from many types of stem cells, such as embryonic, induced pluripotent, mesenchymal, and neural stem cells. This has led to a significant increase in research on brain transplantation treatments. Extended neurodegeneration results in the progressive decline of certain neuronal subtypes or whole neuronal cells. An analysis of the progress made in induced pluripotent and mesenchymal stem cells reveals their significant promise in disease modeling, regeneration, and medication screening. The requirement for stem cells in neurodegenerative disease studies has been crucial in recent years. Stem cells provide the potential for replacing impaired neurons, comprehending disease needs modeling, and creating efficient treatments, but they have many challenges in culturing and acceptability to the host immune cells. The need to use their potential in discovering novel therapies for diseases such as Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis leads to promising therapy. This review examines the function of stem cells in the pathogenesis and treatment of Huntington's disease, Parkinson's disease, Alzheimer's disease, and multiple sclerosis. This review further examines hurdles such as immunological reactions and delivery systems intending to overcome these problems. This article offers a detailed viewpoint on the use of stem cell-based nanotherapies as revolutionary treatments for various neurological illnesses.

Development of a loop-mediated isothermal amplification (LAMP) assay for the rapid detection of Beiji nairovirus.

Beiji nairovirus (BJNV) is a recently discovered tick-borne RNA virus associated with human febrile illness. This study aimed to develop a loop-mediated isothermal amplification (LAMP) assay for the precise detection of BJNV, with a specific focus on assessing its effectiveness with clinical samples. The optimal molecular target was identified as the BJNV small (S) segment gene, and the ideal reaction conditions were established at 65 °C for 50 min. A neutral red stain concentration of 300 μM was determined to be optimal for visualizing the LAMP reaction. The LAMP method demonstrated an impressive lower limit of detection at 10 copies/μL, highlighting a sensitivity level 10,000 times higher than traditional PCR methods. Moreover, it showed no cross-reactivity with three other viruses. The LAMP assay demonstrated results consistent with those of semi-nested PCR when applied to clinical samples, thereby validating its suitability for field testing. In conclusion, the LAMP assay developed in this study represents a significant advancement in the rapid detection of BJNV. Its high sensitivity, specificity, and ease of use make it a valuable tool for the establishment of effective prevention and control strategies against this emerging pathogen.

Exploring Recent Advancements in the Pharmacological Activities of Plant-derived Alkaloids and Glycosides: A Review

A wide spectrum of bioactive compounds is synthesised by plants, and these agents act as protection systems against different living and non-living stressors. They are also useful in the manufacturing of pharmaceutical medications which alleviate a range of human illnesses. Numerous plant metabolites, including glycosides as well as alkaloids, have been studied for potential uses as antioxidants and medicinal agents. Numerous research assessed the modes of action of compounds, therapeutic and pharmacological uses and noteworthy health advantages (such as antifungal, anti-swelling, antimicrobial and anti-tumour applications). As such, a bid has been made to offer an overview of the most recent research that has been done into the secondary metabolites found in medicinal plants. Major Findings: Recent advances in the pharmacological activity of plant-derived alkaloids and glycosides emphasize their expanded therapeutic potential through better drug delivery mechanisms and synergistic uses.

Characterization and genome analysis of lytic Vibrio phage VPK8 with potential in lysing Vibrio parahaemolyticus isolates from clinical and seafood sources

BackgroundVibrio parahaemolyticus is a marine bacterium causing seafood-associated gastrointestinal illness in humans and acute hepatopancreatic necrosis disease (AHPND) in shrimp. Bacteriophages have emerged as promising biocontrol agents against V. parahaemolyticus. This study characterizes Vibrio phage VPK8, focusing on host specificity, efficiency of plating (EOP) variability across V. parahaemolyticus isolates from diverse sources and other Vibrio species, morphology, genomic features, and bacteriolytic potential.MethodsVibrio phage VPK8 was isolated from blood cockles in Thailand using a mixed-host approach and purified via the double-layer agar method. Host specificity was evaluated using spot assays and EOP measurements against 120 Vibrio strains, including AHPND-associated, clinical, and seafood isolates. Phage morphology was characterized by transmission electron microscopy (TEM), while genomic features were analyzed using next-generation sequencing. Lytic characteristics, including latent period and burst size, were determined through one-step growth curves, and bacterial growth reduction was evaluated over a 24-h.ResultsVibrio phage VPK8 is a lytic phage with a 42,866 bp linear double-stranded genome, G + C content of 49.4%, and 48 coding sequences. Phylogenetic analysis grouped it within the Autographiviridae family, showing 95.96% similarity to Vibrio phage vB_VpaP_MGD1. Viral proteomic analysis placed VPK8 within the Pseudomonadota host group. Spot assays indicated broad lytic activity, but EOP analysis revealed high infectivity in clinical and seafood V. parahaemolyticus isolates, as well as some V. cholerae and V. mimicus strains. TEM revealed an icosahedral head (~ 60 nm) and a short tail. At a multiplicity of infection of 0.01, VPK8 exhibited a latent period of 25 min, a burst size of 115, and effectively inhibited the reference host V. parahaemolyticus PSU5124 within 6 h, maintaining its lytic activity and stability for over 24 h.ConclusionsThis study provides a detailed characterization of Vibrio phage VPK8 which exhibits targeted infectivity with high EOP in clinical and seafood V. parahaemolyticus isolates, as well as selected Vibrio species. Its stable lytic performance, rapid replication, and genomic safety suggest its potential for phage-based applications. Further studies should explore its in vivo efficacy and the genetic features contributing to phage resistance mechanisms, enhancing its potential applicability in managing Vibrio-related diseases.

Persistent cross-species transmission systems dominate Shiga toxin-producing Escherichia coli O157:H7 epidemiology in a high incidence region: A genomic epidemiology study

Several areas of the world suffer a notably high incidence of Shiga toxin-producing Escherichia coli. To assess the impact of persistent cross-species transmission systems on the epidemiology of E. coli O157:H7 in Alberta, Canada, we sequenced and assembled E. coli O157:H7 isolates originating from collocated cattle and human populations, 2007–2015. We constructed a timed phylogeny using BEAST2 using a structured coalescent model. We then extended the tree with human isolates through 2019 to assess the long-term disease impact of locally persistent lineages. During 2007–2015, we estimated that 88.5% of human lineages arose from cattle lineages. We identified 11 persistent lineages local to Alberta, which were associated with 38.0% (95% CI 29.3%, 47.3%) of human isolates. During the later period, six locally persistent lineages continued to be associated with human illness, including 74.7% (95% CI 68.3%, 80.3%) of reported cases in 2018 and 2019. Our study identified multiple locally evolving lineages transmitted between cattle and humans persistently associated with E. coli O157:H7 illnesses for up to 13 y. Locally persistent lineages may be a principal cause of the high incidence of E. coli O157:H7 in locations such as Alberta and provide opportunities for focused control efforts.

Persistent cross-species transmission systems dominate Shiga toxin-producing Escherichia coli O157:H7 epidemiology in a high incidence region: A genomic epidemiology study.

Several areas of the world suffer a notably high incidence of Shiga toxin-producing Escherichia coli. To assess the impact of persistent cross-species transmission systems on the epidemiology of E. coli O157:H7 in Alberta, Canada, we sequenced and assembled E. coli O157:H7 isolates originating from collocated cattle and human populations, 2007-2015. We constructed a timed phylogeny using BEAST2 using a structured coalescent model. We then extended the tree with human isolates through 2019 to assess the long-term disease impact of locally persistent lineages. During 2007-2015, we estimated that 88.5% of human lineages arose from cattle lineages. We identified 11 persistent lineages local to Alberta, which were associated with 38.0% (95% CI 29.3%, 47.3%) of human isolates. During the later period, six locally persistent lineages continued to be associated with human illness, including 74.7% (95% CI 68.3%, 80.3%) of reported cases in 2018 and 2019. Our study identified multiple locally evolving lineages transmitted between cattle and humans persistently associated with E. coli O157:H7 illnesses for up to 13 y. Locally persistent lineages may be a principal cause of the high incidence of E. coli O157:H7 in locations such as Alberta and provide opportunities for focused control efforts.

Prevalence and pathogenic potential of Shewanella species in oysters and seawater collected from the Chesapeake Bay and Maryland Coastal Bays

Shewanella is a genus of Gram-negative marine bacteria with some species associated with human and shellfish illnesses. This study evaluated the abundance of Shewanella species in oysters and seawater from the Chesapeake and Maryland Coastal Bays at four sites between 2019 and 2021. Physicochemical parameters such as temperature, salinity, dissolved oxygen, turbidity, pH, chlorophyll-a, rainfall within the last 48 h, total dissolved solids, and atmospheric pressure were also recorded to evaluate if there was a correlation between environmental parameters and the level of Shewanella. The highest total Shewanella counts were 1.8 × 107 CFU/g in oysters and 4.0 × 102 CFU/mL in seawater. 16S rRNA sequencing was performed on 1,344 representative isolates of which 890 (713 oyster, 177 seawater) were confirmed as Shewanella within 16 species. The top four species isolated from oysters and seawater were S. khirikhana a known shrimp pathogen (49%), S. marisflavi (19%), S. loihica (11%), and S. algae (8%). Testing for alpha and beta hemolysis were performed on all confirmed Shewanella isolates. Beta hemolysis was observed in 405 (46%) of the isolates of which 313 were in oysters and 92 in seawater. In oysters, beta-hemolysis was most prevalent in S. khirikhana (233 of 344 isolates, 68%), while in seawater 64 of 92 isolates (70%) were beta-hemolytic strains. Beta-hemolysis suggests that these could be potentially pathogenic strains. Correlations were performed between physicochemical attributes of the seawater and Shewanella counts. Only seawater temperature and dissolved oxygen correlated with Shewanella counts (r = 0.45 and − 0.41), respectively. No correlations were observed between the physicochemical parameters and Shewanella abundances in oysters. Results suggest that virulent strains of Shewanella may be present in oysters and seawater from the Chesapeake and Maryland Coastal Bays, perhaps as a consequence of rising seawater temperatures.

Occurrence and cross contamination of Escherichia albertii in retail chicken outlets in Bangladesh.

Escherichia albertii is an emerging zoonotic pathogen linked to human gastrointestinal illnesses, with poultry meats being considered as a key source of human infections. However, there is little information regarding the distribution and characteristics of this bacterium in Bangladesh. This study investigated the occurrence, antimicrobial resistance, and virulence of E. albertii in chicken meats from retail outlets in Bangladesh. We collected samples from 61 dressed chickens across 17 retail shops from 4 upazilas, along with swabs from cloaca, processing utensils, and worker hands. Detection of E. albertii by species-specific PCR revealed substantial occurrence of E. albertii in retail chicken meat (63.9%), cloaca (71.4%), human hand (45.5%), bleeding cone (13.3%) and blade (10%). Almost all the E. albertii isolates (94.4%) exhibited resistance to at least one of the tested antimicrobials, among which 50% were multidrug resistant, including resistance to clinically relevant antimicrobials such as tetracycline, ampicillin, gentamicin, kanamycin, nalidixic acid and ciprofloxacin. Whole genome sequencing analysis identified the presence of corresponding antimicrobial resistance genes and critical virulence genes (eae, Eacdt). Notably, although wgSNP-based phylogenetic analysis showed the genomic diversity of the isolates, some of the isolates from the same shop displayed clonal relationships among meats, cloacal swabs, and human hand swabs, indicating contamination during processing. These findings highlight the public health risk posed by E. albertii in retail poultry, underlining the poultry's role as a potential vector for zoonotic transmission and the need for improved biosecurity and antimicrobial management practices in poultry production.

Antimicrobial Susceptibility and Genomic Characterization of Vibrio cholerae Non-O1/non-O139 Isolated from Clinical and Environmental Samples in Jiaxing City, China.

Non-O1/non-O139 (NOVC) strains inhabit aquatic environments and sporadically induce human illnesses. This study involved the virulence and antimicrobial genetic characterization of 176 NOVC strains, comprising 25 from clinical samples and 151 from environmental sources, collected between 2021 and 2023. The antimicrobial susceptibility of the examined NOVC population was predominantly high, exhibiting only poor susceptibility to colistin, with 89.2% resistance. The examination of virulence genes revealed that the majority of strains were positive for glucose metabolism (als gene) (169/176, 96.0%). Through multilocus sequence typing, the 176 NOVC strains were categorised into 121 sequence types, 79 of which were novel. NOVC strains demonstrate significant genetic variability and frequently engage in recombination. This work offers genetic characterization of the pathogenicity and antimicrobial resistance of a NOVC community. Our findings offer insights that may aid in the development of preventative and treatment methods for this pathogen.

Bioactive Molecules, Ethnomedicinal Uses, Toxicology, and Pharmacology of Peltophorum africanum Sond (Fabaceae): Systematic Review.

Plants have long been used to treat serious illnesses in both humans and animals. A significant underappreciated medicinal tree, Peltophorum africanum Sond is utilized by many different ethnic groups to cure a wide range of illnesses. A variety of electronic databases, including ScienceDirect, Scopus, Scielo, Scifinder, PubMed, Web of Science, Medline, and Google Scholar, were used to search the literature on P. africanum, using key words such as uses, survey, pharmacology, antigonococcal, toxicity, phytochemistry and others. Further data was obtained from several scholarly theses, dissertations, and books on general plant sciences, ethnomedicine, and other pertinent ethnobotanical topics. The plant species possess very important pharmacological activities in vitro, which includes antimicrobial, anti-HIV, antioxidant, anticancer, antidiabetic, and other activities. Phytochemically, the plant possesses various classes of compounds, dominated by flavonols, which may well explain its wider range of pharmacological activities. Although the plant is promising anti-HIV activity, the mode of action and safety profiles of the plant also need to be explored as its extracts exerted some degree of mutagenicity. It is also important to further explore its ethnoveterinary use against a plethora of nematodes that infects both wild and domestic animals. Given its potent pharmacological activity, the further in vivo studies need to be explored to ascertain the comprehensive toxicology of the plant species, thereby developing possible medications. The plant species may further be elevated to a potent pharmaceutical product against plethora of infections.

Investigating causal relationships between plasma proteins and lung adenocarcinoma: result from proteomics and Mendelian randomization study

BackgroundPlasma proteins contribute to the identification, diagnosis, and prognosis of human illnesses, which may be conducive to understanding the molecular mechanism and diagnosis of Lung adenocarcinoma (LUAD).MethodsWe collected plasma samples from 28 healthy individuals (H) and 56 LUAD patients and analyzed them using LC–MS/MS-based proteomics to determine differential expression plasma proteins (DEPPs). Then, the DEPPs were subjected to a two-sample Mendelian randomization (MR) study based on an “Inverse variance weighted (IVW)” approach to investigate the causal relationships between DEPPs and LUAD. Logistic regression analysis was conducted to develop a diagnostic model for LUAD.Results317 plasma proteins were found in proteomics, and 19 DEPPs were identified. The MR study revealed that IL20RB (odds ratio (OR) = 1.600, 95% Confidence Interval (CI) [1.098, 2.331], P = 0.014) and SAA2 (OR = 1.048, 95%CI [1.012, 1.081], P = 0.017) were highly related to LUAD. A diagnostic model was established with IL20RB and SAA2. The AUC of this diagnostic model was 0.858.ConclusionPlasma IL20RB and SAA2 levels were closely connected with LUAD.

Leptospira biofilms: implications for survival, transmission, and disease management.

Leptospirosis is a zoonotic disease caused by Leptospira bacteria, affecting humans and a broad range of wild and domestic animals in diverse epidemiological settings (rural, urban, and wild). The disease's pathogenesis and epidemiology are complex networks not fully elucidated. Epidemiology reflects the One Health integrated approach of environment-animal-human interaction, causing severe illness in humans and animals, with consequent public health burdens. Saprophytic and pathogenic leptospires have been shown to form biofilms in vivo, in vitro, and in environmental samples. Biofilms are characterized by a polymeric matrix that confers protection against hostile environments (both inside and outside of the host), favoring bacterial survival and dissemination. Despite its significance, the role of this bacterial growth mode in leptospiral survival, transmission, and decreased antibiotic susceptibility remains poorly understood and underexplored. Even so, the literature indicates that biofilms might be correlated with lower antimicrobial susceptibility and chronicity in leptospirosis. In this minireview, we discuss the aspects of biofilm formation by Leptospira and their significance for epidemiology and therapeutic management. Understanding the current scenario provides insight into the future prospects for biofilm diagnosis, prevention, and treatment of leptospirosis.

A novel approach for detecting Salmonella enterica strains frequently attributed to human illness-development and validation of the highly pathogenic Salmonella (HPS) multiplex PCR assay.

Non-typhoidal Salmonella enterica (NTS) are leading bacterial agents of foodborne illnesses and a global concern for human health. While there are over 2,600 different serovars of NTS, epidemiological data suggests that certain serovars are better at causing disease than others, resulting in the majority of reported human illnesses in the United States. To improve food safety, there is a need to rapidly detect these more pathogenic serovars to facilitate their removal from the food supply. Addressing this need, we conducted a comparative analysis of 23 closed Salmonella genomic sequences of five serotypes. The analysis pinpointed eight genes (sseK2, sseK3, gtgA/gogA, avrA, lpfB, SspH2, spvD, and invA) that in combination, identify 7 of the 10 leading Salmonella serovars attributed to human illnesses in the US each year (i.e., Serovars of Concern or SoC). A multiplex PCR assay was developed to detect the presence of these genes, with strains amplifying five or more targets designated Highly Pathogenic Salmonella, or HPS. The utility of the resulting HPS assay for identifying SoC was examined in silico, using BLAST to determine the distribution of gene targets among closed Salmonella genome sequences in GenBank (n = 2,192 representing 148 serotypes) and by assaying 1,303 Salmonella (69 serotypes), isolated from FSIS regulatory samples. Comparison of serotypes identified by the assay as HPS, with those identified as SoC, produced an Area Under the Curve (AUC) of 92.2% with a specificity of 96% and a positive predictive value of 97.4%, indicating the HPS assay has strong ability to identify SoC. The data presented lay the groundwork for development of rapid commercial assays for the detection of SoC.

Inhibitory Effects of Natural Products on Germination, Outgrowth, and Vegetative Growth of Clostridium perfringens Spores in Laboratory Medium and Chicken Meat.

Clostridium perfringens type F is a spore-forming bacterium that causes human illnesses, including food poisoning (FP) and non-foodborne gastrointestinal diseases. In this study, we evaluated the antimicrobial activities of 15 natural products against C. perfringens spore growth. Among them, garlic, onion juice, and undiluted essential oil constituents (EOCs) of clove, rosemary, and peppermint showed the strongest activity. Therefore, we examined the inhibitory effects of these products on each stage of the life cycle of C. perfringens FP strains, including spore germination, spore outgrowth, and vegetative growth, in laboratory media and chicken meat. Both clove and peppermint oils (at 0.5%; v/v) inactivated C. perfringens spore germination in nutrient-rich trypticase-glucose-yeast extract (TGY) medium. Furthermore, EOCs at (0.1-0.5%) arrested the spore outgrowth of C. perfringens in TGY medium. Interestingly, EOCs at 0.5% completely inhibited the vegetative growth of FP isolates during a 6 h incubation in TGY medium. However, even at 4-fold higher concentrations (2%), EOCs were unable to inactivate C. perfringens spore growth in contaminated chicken meat stored under abusive conditions. Although some of the natural products inhibited C. perfringens spore germination, outgrowth, and vegetative growth in TGY medium, no such inhibitory activity was observed when these products were applied to C. perfringens spore-inoculated chicken meat.

ZBP1-driven cell death in severe influenza.

Influenza A virus (IAV) infections can cause life-threatening illness in humans. The severity of disease is directly linked to virus replication in the alveoli of the lower respiratory tract. In particular, the lytic death of infected alveolar epithelial cells (AECs) is a major driver of influenza severity. Recent studies have begun to define the molecular mechanisms by which IAV triggers lytic cell death. Z-form nucleic-acid-binding protein 1 (ZBP1) senses replicating IAV and drives programmed cell death (PCD) in infected cells, including apoptosis and necroptosis in AECs and pyroptosis in myeloid cells. Necroptosis and pyroptosis, both lytic forms of death, contribute to pathogenesis during severe infections. Pharmacological blockade of necroptosis shows strong therapeutic potential in mouse models of lethal influenza. We suggest that targeting ZBP1-initiated necroinflammatory cell lysis, either alone or in combination antiviral drugs, will provide clinical benefit in severe influenza.

Understanding Influenza.

Influenza, a serious illness of humans and domesticated animals, has been studied intensively for many years. It therefore provides an example of how much we can learn from detailed studies of an infectious disease, and of how even the most intensive scientific research leaves further questions to answer. This introduction is written for researchers who have become interested in one of these unanswered questions, but who may not have previously worked on influenza. To investigate these questions, researchers must not only have a firm grasp of relevant methods and protocols; they must also be familiar with the basic details of our current understanding of influenza. This chapter briefly covers the burden of disease that has driven influenza research, summarizes how our thinking about influenza has evolved over time, and sets out key features of influenza viruses by discussing how we classify them and what we currentlyunderstand of their replication. It does not aim to be comprehensive, as any researcher will read deeply into the specific areas that have grasped their interest. Instead, it aims to provide a general summary of how we came to think about influenza in the way we do now, in the hope that the reader's ownresearch will help us to understand it better.

Plasmidome of Salmonella enterica serovar Infantis recovered from surface waters in a major agricultural region for leafy greens in California.

Non-typhoidal Salmonella enterica is a leading cause of gastrointestinal illnesses in the United States. Among the 2,600 different S. enterica serovars, Infantis has been significantly linked to human illnesses and is frequently recovered from broilers and chicken parts in the U.S. A key virulence determinant in serovar Infantis is the presence of the megaplasmid pESI, conferring multidrug resistance. To further characterize the virulence potential of this serovar, the present study identified the types of plasmids harbored by Infantis strains, recovered from surface waters adjacent to leafy greens farms in California. Sequencing analysis showed that each of the examined 12 Infantis strains had a large plasmid ranging in size from 78 kb to 125 kb. In addition, a second 4-kb plasmid was detected in two strains. Plasmid nucleotide queries did not identify the emerging megaplasmid pESI in the examined Infantis strains; however, the detected plasmids each had similarity to a plasmid sequence already cataloged in the nucleotide databases. Subsequent comparative analyses, based on gene presence or absence, divided the detected plasmids into five distinct clusters, and the phylogram revealed these Infantis plasmids were clustered based either on the plasmid conjugation system, IncI and IncF, or on the presence of plasmid phage genes. Assignment of the putative genes to functional categories revealed that the large plasmids contained genes implicated in cell cycle control and division, replication and recombination and defense mechanisms. Further analysis of the mobilome, including prophages and transposons, demonstrated the presence of genes implicated in the release of the bactericidal peptide microcin in the IncF plasmids and identified a Tn10 transposon conferring tetracycline resistance in one of the IncI1 plasmids. These findings indicated that the plasmids in the environmental S. enterica serovar Infantis strains from surface waters harbored a wide variety of genes associated with adaptation, survivability and antimicrobial resistance.