Precision Diabetes Education and Support Considering Patients' Behavioral and Psychological Phenotype: A Q-Methodology Study.

BACKGROUND: The prevalence of type 2 diabetes is growing, and diabetes burden is increasing. Precision health in diabetes education and support employs different intervention strategies, depending on an individual's viewpoint on diabetes and self-management behaviors, to improve patients' treatment adherence, clinical outcomes, and quality of life. OBJECTIVE: To classify the behavioral and psychological phenotypes of self-management behaviors in adults taking oral glucose-lowering medications to develop a theory-driven, person-centered group intervention applicable to busy clinical settings. METHODS: Q-methodology was used. From January to August 2020, 73 participants (48 male, 25 female) were invited to do Q-sorting with 33 statements. The principal component technique, followed by varimax rotation, was used for factor analysis. The Summary of Diabetes Self-Care Activity questionnaire and HbA1c in the past 6 months were included to obtain comprehensive understanding. RESULTS: Fifty-one sorts (35 male, 16 female) loaded on 1 of 4 factors: factor A (n = 18): Needing emotional support with enhancing problem-solving skills group; factor B (n = 15): Self-help group; factor C (n = 6): Needing personalized coaching group; and factor D (n = 12): Needing basic diabetes education group. CONCLUSIONS: Each factor demonstrated a different need for diabetes education and support. Younger participants (factor D) had the poorest diabetes self-management behaviors and required basic diabetes education. Further research is warranted to develop a screening tool to classify the typologies and adopt the findings in a busy clinical setting.

Host-microbiome associations in saliva predict COVID-19 severity.

Established evidence indicates that oral microbiota plays a crucial role in modulating host immune responses to viral infection. Following severe acute respiratory syndrome coronavirus 2, there are coordinated microbiome and inflammatory responses within the mucosal and systemic compartments that are unknown. The specific roles the oral microbiota and inflammatory cytokines play in the pathogenesis of coronavirus disease 2019 (COVID-19) are yet to be explored. Here, we evaluated the relationships between the salivary microbiome and host parameters in different groups of COVID-19 severity based on their oxygen requirement. Saliva and blood samples (n = 80) were collected from COVID-19 and from noninfected individuals. We characterized the oral microbiomes using 16S ribosomal RNA gene sequencing and evaluated saliva and serum cytokines and chemokines using multiplex analysis. Alpha diversity of the salivary microbial community was negatively associated with COVID-19 severity, while diversity increased with health. Integrated cytokine evaluations of saliva and serum showed that the oral host response was distinct from the systemic response. The hierarchical classification of COVID-19 status and respiratory severity using multiple modalities separately (i.e. microbiome, salivary cytokines, and systemic cytokines) and simultaneously (i.e. multimodal perturbation analyses) revealed that the microbiome perturbation analysis was the most informative for predicting COVID-19 status and severity, followed by the multimodal. Our findings suggest that oral microbiome and salivary cytokines may be predictive of COVID-19 status and severity, whereas atypical local mucosal immune suppression and systemic hyperinflammation provide new cues to understand the pathogenesis in immunologically compromised populations.

Oral mucosa immunity: ultimate strategy to stop spreading of pandemic viruses.

Global pandemics are most likely initiated via zoonotic transmission to humans in which respiratory viruses infect airways with relevance to mucosal systems. Out of the known pandemics, five were initiated by respiratory viruses including current ongoing coronavirus disease 2019 (COVID-19). Striking progress in vaccine development and therapeutics has helped ameliorate the mortality and morbidity by infectious agents. Yet, organism replication and virus spread through mucosal tissues cannot be directly controlled by parenteral vaccines. A novel mitigation strategy is needed to elicit robust mucosal protection and broadly neutralizing activities to hamper virus entry mechanisms and inhibit transmission. This review focuses on the oral mucosa, which is a critical site of viral transmission and promising target to elicit sterile immunity. In addition to reviewing historic pandemics initiated by the zoonotic respiratory RNA viruses and the oral mucosal tissues, we discuss unique features of the oral immune responses. We address barriers and new prospects related to developing novel therapeutics to elicit protective immunity at the mucosal level to ultimately control transmission.

Persistent immune and clotting dysfunction detected in saliva and blood plasma after COVID-19.

A growing number of studies indicate that coronavirus disease 2019 (COVID-19) is associated with inflammatory sequelae, but molecular signatures governing the normal versus pathologic convalescence process have not been well-delineated. Here, we characterized global immune and proteome responses in matched plasma and saliva samples obtained from COVID-19 patients collected between 20 and 90 days after initial clinical symptoms resolved. Convalescent subjects showed robust total IgA and IgG responses and positive antibody correlations in saliva and plasma samples. Shotgun proteomics revealed persistent inflammatory patterns in convalescent samples including dysfunction of salivary innate immune cells, such as neutrophil markers (e.g., myeloperoxidase), and clotting factors in plasma (e.g., fibrinogen), with positive correlations to acute COVID-19 disease severity. Saliva samples were characterized by higher concentrations of IgA, and proteomics showed altered myeloid-derived pathways that correlated positively with SARS-CoV-2 IgA levels. Beyond plasma, our study positions saliva as a viable fluid to monitor normal and aberrant immune responses including vascular, inflammatory, and coagulation-related sequelae.

Host-Microbiome Associations in Saliva Predict COVID-19 Severity.

Established evidence indicates that oral microbiota plays a crucial role in modulating host immune responses to viral infection. Following Severe Acute Respiratory Syndrome Coronavirus 2 - SARS-CoV-2 - there are coordinated microbiome and inflammatory responses within the mucosal and systemic compartments that are unknown. The specific roles that the oral microbiota and inflammatory cytokines play in the pathogenesis of COVID-19 are yet to be explored. We evaluated the relationships between the salivary microbiome and host parameters in different groups of COVID-19 severity based on their Oxygen requirement. Saliva and blood samples (n = 80) were collected from COVID-19 and from non-infected individuals. We characterized the oral microbiomes using 16S ribosomal RNA gene sequencing and evaluated saliva and serum cytokines using Luminex multiplex analysis. Alpha diversity of the salivary microbial community was negatively associated with COVID-19 severity. Integrated cytokine evaluations of saliva and serum showed that the oral host response was distinct from the systemic response. The hierarchical classification of COVID-19 status and respiratory severity using multiple modalities separately (i.e., microbiome, salivary cytokines, and systemic cytokines) and simultaneously (i.e., multi-modal perturbation analyses) revealed that the microbiome perturbation analysis was the most informative for predicting COVID-19 status and severity, followed by the multi-modal. Our findings suggest that oral microbiome and salivary cytokines may be predictive of COVID-19 status and severity, whereas atypical local mucosal immune suppression and systemic hyperinflammation provide new cues to understand the pathogenesis in immunologically naïve populations.

Influenza virus immune imprinting dictates the clinical outcomes in ferrets challenged with highly pathogenic avian influenza virus H5N1.

Zoonotic transmission of H5N1 highly pathogenic avian influenza virus (HPAIV) into the human population is an increasing global threat. The recent 2022 HPAIV outbreak significantly highlighted this possibility, increasing concern in the general population. The clinical outcomes of H5N1 influenza virus exposure can be determined by an individual's primary influenza virus infection (imprinting) or vaccination status. Immunological imprinting with Group 1 - (H1N1, H2N2, and H2N3) increases survival rates following H5N1 viral infection compared to Group 2 - (H3N2) imprinted individuals. Vaccination against H5N1 influenza viruses can offer protection to at-risk populations; however, stockpiled inactivated H5N1 influenza vaccines are not readily available to the public. We hypothesize that the immunological response to vaccination and subsequent clinical outcome following H5N1 influenza virus infection is correlated with the immunological imprinting status of an individual. To test this hypothesis, our lab established a ferret pre-immune model of disease. Naïve ferrets were intranasally inoculated with seasonal influenza viruses and allowed to recover for 84 days prior to H5N1 virus infection. Ferrets imprinted following H1N1 and H2N3 virus infections were completely protected against lethal H5N1 influenza virus challenge (100% survival), with few to no clinical symptoms. In comparison, H3N2 influenza virus-imprinted ferrets had severe clinical symptoms, delayed disease progression, and a sublethal phenotype (40% mortality). Consecutive infections with H1N1 influenza viruses followed by an H3N2 influenza virus infection did not abrogate the immune protection induced by the original H1N1 influenza virus infection. In addition, ferrets consecutively infected with H1N1 and H2N3 viruses had no clinical symptoms or weight loss. H3N2 pre-immune ferrets were vaccinated with a broadly reactive H5 HA-based or H1 NA-based vaccine (Hu-CO 2). These ferrets were protected against H5N1 influenza virus challenge, whereas ferrets vaccinated with the H1N1 wild-type CA/09 rHA vaccine had similar phenotypes as non-vaccinated H3N2-imprinted ferrets with 40% survival. Overall, Group 2 imprinted ferrets, which were vaccinated with heterologous Group 1 HA vaccines, had redirected immune responses to Group 1 influenza viral antigens and rescued a sublethal phenotype to complete protection.

Novel H7N9 influenza immunogen design enhances mobilization of seasonal influenza T cell memory in H3N2 pre-immune mice.

Strategies that improve influenza vaccine immunogenicity are critical for the development of vaccines for pandemic preparedness. Hemagglutinin (HA)-specific CD4+ T cell epitopes support protective B cell responses against seasonal influenza. However, in the case of avian H7N9, which poses a pandemic threat, HA elicits only weak neutralizing antibody responses in infection and vaccination without adjuvant. We hypothesized that an immune-engineered H7N9 HA incorporating a broadly reactive H3N2 HA-specific memory CD4+ T cell epitope that replaces a regulatory T cell-inducing epitope at the corresponding position in H7N9 HA could harness preexisting influenza T cell immunity to increase CD4+ T cells that are needed for protective antibody development. We designed and produced a virus-like particle (VLP) vaccine that carries the epitope augmented H7N9 HA (OPT1) and immunized HLA-DR3 transgenic mice with established H3N2 immunity. OPT1-VLPs stimulated higher stem cell, central, and effector memory CD4+ T cell levels over wild type VLP immunization. In addition, activated, IL-21-producing follicular helper T cell frequencies were enhanced. This novel immunogen design strategy illustrates that site-specific modifications aimed to augment T cell epitope content enhance CD4+ T cell responses among critical subpopulations capable of aiding protective immune responses upon antigen re-encounter and that mobilization of immune memory can be used to overcome the poor immunogenicity of avian influenza viruses.

Q-Methodology and Psychological Phenotyping to Design Patient-Centered Diabetes Education for Persons With Type 2 Diabetes on Insulin Therapy.

PURPOSE: The purpose of this study was to identify the psychological phenotypes of persons with type 2 diabetes (T2D) on insulin therapy to better inform personalized diabetes education strategies to improve self-management behaviors. METHODS: Q-methodology, a research approach combining the quantitative rigor of statistical analysis with qualitative data on perception of diabetes self-management by persons with T2D on insulin therapy, was used. The Summary of Diabetes Self-Care Activity measure and A1C in the past 6 months were used to further describe self-management behaviors of each P-sample, Q-sorter. Of 160 statements, 33 Q-sample statements were selected as Q-set. Then, 37 P-samples (24 men; 13 women) were recruited from a university-affiliated diabetes clinic in South Korea. Data obtained from each P-sample with a Q-set and a Q-sorting table, a forced-choice normal distribution table, were analyzed using varimax rotation. RESULTS: Forty-one percent of the variance was explained with 5 factors represented by 27 Q-sorters, explaining variance ranging from 5% to 17% for each factor: Factor A (n = 6): those showing self-management education need but possessing inadequate health literacy; Factor B (n = 4): those valuing lifestyle modification to control diabetes; Factor C (n = 5): those valuing antidiabetic medication to control diabetes; Factor D (n = 6): carpe diem, accepting diabetes as destiny; and Factor E (n = 6): those overestimating their competencies to control diabetes. Ten Q-sorters fell into either confounded or nonsignificant. CONCLUSIONS: Tailoring messages and educational approaches based on patients' psychological phenotypes are necessary to promote optimal self-management behaviors.

SARS-CoV-2 and Influenza A Virus Coinfections in Ferrets.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and seasonal influenza viruses are cocirculating in the human population. However, only a few cases of viral coinfection with these two viruses have been documented in humans with some people having severe disease and others mild disease. To examine this phenomenon, ferrets were coinfected with SARS-CoV-2 and human seasonal influenza A viruses (IAVs; H1N1 or H3N2) and were compared to animals that received each virus alone. Ferrets were either immunologically naive to both viruses or vaccinated with the 2019 to 2020 split-inactivated influenza virus vaccine. Coinfected naive ferrets lost significantly more body weight than ferrets infected with each virus alone and had more severe inflammation in both the nose and lungs compared to that of ferrets that were single infected with each virus. Coinfected, naive animals had predominantly higher IAV titers than SARS-CoV-2 titers, and IAVs were efficiently transmitted by direct contact to the cohoused ferrets. Comparatively, SARS-CoV-2 failed to transmit to the ferrets that cohoused with coinfected ferrets by direct contact. Moreover, vaccination significantly reduced IAV titers and shortened the viral shedding but did not completely block direct contact transmission of the influenza virus. Notably, vaccination significantly ameliorated influenza-associated disease by protecting vaccinated animals from severe morbidity after IAV single infection or IAV and SARS-CoV-2 coinfection, suggesting that seasonal influenza virus vaccination is pivotal to prevent severe disease induced by IAV and SARS-CoV-2 coinfection during the COVID-19 pandemic. IMPORTANCE Influenza A viruses cause severe morbidity and mortality during each influenza virus season. The emergence of SARS-CoV-2 infection in the human population offers the opportunity to potential coinfections of both viruses. The development of useful animal models to assess the pathogenesis, transmission, and viral evolution of these viruses as they coinfect a host is of critical importance for the development of vaccines and therapeutics. The ability to prevent the most severe effects of viral coinfections can be studied using effect coinfection ferret models described in this report.

SARS-CoV-2 mRNA Vaccines Elicit Different Responses in Immunologically Naïve and Pre-Immune Humans.

As the COVID-19 pandemic continues, the authorization of vaccines for emergency use has been crucial in slowing down the rate of infection and transmission of the SARS-CoV-2 virus that causes COVID-19. In order to investigate the longitudinal serological responses to SARS-CoV-2 natural infection and vaccination, a large-scale, multi-year serosurveillance program entitled SPARTA (SARS SeroPrevalence and Respiratory Tract Assessment) was initiated at 4 locations in the U.S. The serological assay presented here measuring IgG binding to the SARS-CoV-2 receptor binding domain (RBD) detected antibodies elicited by SARS-CoV-2 infection or vaccination with a 95.5% sensitivity and a 95.9% specificity. We used this assay to screen more than 3100 participants and selected 20 previously infected pre-immune and 32 immunologically naïve participants to analyze their antibody binding to RBD and viral neutralization (VN) responses following vaccination with two doses of either the Pfizer-BioNTech BNT162b2 or the Moderna mRNA-1273 vaccine. Vaccination not only elicited a more robust immune reaction than natural infection, but the level of neutralizing and anti-RBD antibody binding after vaccination is also significantly higher in pre-immune participants compared to immunologically naïve participants (p<0.0033). Furthermore, the administration of the second vaccination did not further increase the neutralizing or binding antibody levels in pre-immune participants (p=0.69). However, ~46% of the immunologically naïve participants required both vaccinations to seroconvert.

Influence of the H1N1 influenza pandemic on the humoral immune response to seasonal flu vaccines.

In this study, we hypothesized that the humoral response to trivalent seasonal influenza virus vaccines was influenced by rapid antigenic switching of H1 HA. We tested archived sera and peripheral blood mononuclear cells (PBMC) collected at prior to vaccination at day 0, as well as days 30 and 90 after vaccination during the 2009/2010 and 2010/2011 influenza virus seasons. During the 2009/2010 season, vaccination successfully induced antibodies with hemagglutinin inhibition (HAI) activity against both H1N1 and H3N2 vaccine components. For the 2010/2011 season, the A/California/04/2009 (CA/09) H1N1 elicited seroconversion (HAI titer = 1:40) and novel memory B cell (Bmem) responses from most individuals. However, the H3N2 influenza virus component of the vaccine, A/Perth/16/2009 (Perth/09), back-boosted and elicited antibodies with HAI activity and Bmem response to historical H3N2 influenza virus strains. Following stratification of the pre-existing antibody with HAI against the CA/09 H1N1, there was a negative correlation with HAI seroconversion to other vaccine strains. Overall, strong immune responses against CA/09 H1N1 influenza virus negatively influenced the induction of novel humoral responses.

Immunisation of ferrets and mice with recombinant SARS-CoV-2 spike protein formulated with Advax-SM adjuvant protects against COVID-19 infection.

The development of a safe and effective vaccine is a key requirement to overcoming the COVID-19 pandemic. Recombinant proteins represent the most reliable and safe vaccine approach but generally require a suitable adjuvant for robust and durable immunity. We used the SARS-CoV-2 genomic sequence and in silico structural modelling to design a recombinant spike protein vaccine (Covax-19™). A synthetic gene encoding the spike extracellular domain (ECD) was inserted into a baculovirus backbone to express the protein in insect cell cultures. The spike ECD was formulated with Advax-SM adjuvant and first tested for immunogenicity in C57BL/6 and BALB/c mice. Covax-19 vaccine induced high spike protein binding antibody levels that neutralised the original lineage B.1.319 virus from which the vaccine spike protein was derived, as well as the variant B.1.1.7 lineage virus. Covax-19 vaccine also induced a high frequency of spike-specific CD4 + and CD8 + memory T-cells with a dominant Th1 phenotype associated with the ability to kill spike-labelled target cells in vivo. Ferrets immunised with Covax-19 vaccine intramuscularly twice 2 weeks apart made spike receptor binding domain (RBD) IgG and were protected against an intranasal challenge with SARS-CoV-2 virus given two weeks after the last immunisation. Notably, ferrets that received the two higher doses of Covax-19 vaccine had no detectable virus in their lungs or in nasal washes at day 3 post-challenge, suggesting that in addition to lung protection, Covax-19 vaccine may have the potential to reduce virus transmission. This data supports advancement of Covax-19 vaccine into human clinical trials.

Functional characterization of SARS-CoV-2 vaccine elicited antibodies in immunologically naïve and pre-immune humans.

As the COVID-19 pandemic continues, the authorization of vaccines for emergency use has been crucial in slowing down the rate of infection and transmission of the SARS-CoV-2 virus that causes COVID-19. In order to investigate the longitudinal serological responses to SARS-CoV-2 natural infection and vaccination, a large-scale, multi-year serosurveillance program entitled SPARTA (SARS SeroPrevalence and Respiratory Tract Assessment) was initiated at 4 locations in the U.S. The serological assay presented here measuring IgG binding to the SARS-CoV-2 receptor binding domain (RBD) detected antibodies elicited by SARS-CoV-2 infection or vaccination with a 95.5% sensitivity and a 95.9% specificity. We used this assay to screen more than 3100 participants and selected 20 previously infected pre-immune and 32 immunologically naïve participants to analyze their antibody binding to RBD and viral neutralization (VN) responses following vaccination with two doses of either the Pfizer-BioNTech BNT162b2 or the Moderna mRNA-1273 vaccine. Vaccination not only elicited a more robust immune reaction than natural infection, but the level of neutralizing and anti-RBD antibody binding after vaccination is also significantly higher in pre-immune participants compared to immunologically naïve participants (p<0.0033). Furthermore, the administration of the second vaccination did not further increase the neutralizing or binding antibody levels in pre-immune participants (p=0.69). However, ~46% of the immunologically naïve participants required both vaccinations to seroconvert.

Client-Centered Breastfeeding-Promotion Strategies: Q Methodology.

Fewer Korean women are choosing the 6 months of exclusive breastfeeding that are recommended for obtaining its maximal benefits despite an increasing effort to promote breastfeeding. Successful breastfeeding education and counseling need to be segmentally designed on the basis of client characteristics. This study explored the perceptions of breastfeeding in pregnant and 6 month postpartum Korean women using the Q methodology, a useful research approach to examine personal perceptions, feelings, and values about a concept or phenomenon of interest and identify typologies of perspectives. The Q sample consisted of 38 statements representing the universe of viewpoints on breastfeeding. The P sample (N = 49) included women who shared their perceptions of breastfeeding and filled each grid with a statement in the Q sorting table. Data were analyzed using the PC-QUANL program. Varimax (orthogonal) rotation revealed four factors that explained 53.0% of variance: maternal privilege (Factor 1), option based on emotion (Factor 2), option if efficient (Factor 3), and option if I have sufficient problem-solving skills (Factor 4). Korean women have changed their attitudes toward breastfeeding, with all participants viewing breastfeeding as optional. Breastfeeding-promotion campaigns and education need to consider societal norms and changes in women's beliefs and perceptions.

Human neutralizing antibodies against SARS-CoV-2 require intact Fc effector functions for optimal therapeutic protection.

SARS-CoV-2 has caused the global COVID-19 pandemic. Although passively delivered neutralizing antibodies against SARS-CoV-2 show promise in clinical trials, their mechanism of action in vivo is incompletely understood. Here, we define correlates of protection of neutralizing human monoclonal antibodies (mAbs) in SARS-CoV-2-infected animals. Whereas Fc effector functions are dispensable when representative neutralizing mAbs are administered as prophylaxis, they are required for optimal protection as therapy. When given after infection, intact mAbs reduce SARS-CoV-2 burden and lung disease in mice and hamsters better than loss-of-function Fc variant mAbs. Fc engagement of neutralizing antibodies mitigates inflammation and improves respiratory mechanics, and transcriptional profiling suggests these phenotypes are associated with diminished innate immune signaling and preserved tissue repair. Immune cell depletions establish that neutralizing mAbs require monocytes and CD8+ T cells for optimal clinical and virological benefit. Thus, potently neutralizing mAbs utilize Fc effector functions during therapy to mitigate lung infection and disease.

Extremely potent human monoclonal antibodies from COVID-19 convalescent patients.

Human monoclonal antibodies are safe, preventive, and therapeutic tools that can be rapidly developed to help restore the massive health and economic disruption caused by the coronavirus disease 2019 (COVID-19) pandemic. By single-cell sorting 4,277 SARS-CoV-2 spike protein-specific memory B cells from 14 COVID-19 survivors, 453 neutralizing antibodies were identified. The most potent neutralizing antibodies recognized the spike protein receptor-binding domain, followed in potency by antibodies that recognize the S1 domain, the spike protein trimer, and the S2 subunit. Only 1.4% of them neutralized the authentic virus with a potency of 1-10 ng/mL. The most potent monoclonal antibody, engineered to reduce the risk of antibody-dependent enhancement and prolong half-life, neutralized the authentic wild-type virus and emerging variants containing D614G, E484K, and N501Y substitutions. Prophylactic and therapeutic efficacy in the hamster model was observed at 0.25 and 4 mg/kg respectively in absence of Fc functions.

Hemagglutination Inhibition (HAI) antibody landscapes after vaccination with H7Nx virus like particles.

BACKGROUND: A systemic evaluation of the antigenic differences of the H7 influenza hemagglutinin (HA) proteins, especially for the viruses isolated after 2016, are limited. The purpose of this study was to investigate the antigenic differences of major H7 strains with an ultimate aim to discover H7 HA proteins that can elicit protective receptor-binding antibodies against co-circulating H7 influenza strains. METHOD: A panel of eight H7 influenza strains were selected from 3,633 H7 HA amino acid sequences identified over the past two decades (2000-2018). The sequences were expressed on the surface of virus like particles (VLPs) and used to vaccinate C57BL/6 mice. Serum samples were collected and tested for hemagglutination-inhibition (HAI) activity. The vaccinated mice were challenged with lethal dose of H7N9 virus, A/Anhui/1/2013. RESULTS: VLPs expressing the H7 HA antigens elicited broadly reactive antibodies each of the selected H7 HAs, except the A/Turkey/Italy/589/2000 (Italy/00) H7 HA. A putative glycosylation due to an A169T substitution in antigenic site B was identified as a unique antigenic profile of Italy/00. Introduction of the putative glycosylation site (H7 HA-A169T) significantly altered the antigenic profile of HA of the A/Anhui/1/2013 (H7N9) strain. CONCLUSION: This study identified key amino acid mutations that result in severe vaccine mismatches for future H7 epidemics. Future universal influenza vaccine candidates will need to focus on viral variants with these key mutations.

Prevalence, biosecurity factor, and antimicrobial susceptibility analysis of Salmonella species isolated from commercial duck farms in Korea.

Duck meat consumption in South Korea has increased in recent years, but no standard about duck farm-specific biosecurity and hygiene guidelines have yet been established. We here investigated Salmonella contamination levels in duck farms to evaluate biosecurity and hygiene practices. We collected 1,116 environmental samples from 31 duck farms in Jeonnam Province, South Korea. The Salmonella-positive farm rate dramatically increased, from 22.6 to 71.0%, on introduction of ducklings. As the ducklings aged 4-6 wk, the positive rate slightly decreased to 64.5%. The Salmonella detection rate on each sampled surface, such as the feed pan (34.4%), wall (33.9%), litter (32.3%), and nipples (24.2%), was highest at 3 wk of age. The most frequently detected Salmonella serovars were Salmonella London (22.2%), Salmonella Albany (21.6%), Salmonella Bareilly (17.0%), and Salmonella Indiana (16.5%). Implementation of cleaning and disinfection procedures, rodent control, and metal house walls significantly lowered the prevalence of Salmonella (P < 0.001, P < 0.01, and P < 0.05, respectively). A high proportion of Salmonella isolates exhibited antimicrobial resistance: 100 and 62.9% exhibited resistance to erythromycin and nalidixic acid, respectively. Furthermore, a majority of S. Albany and all Salmonella Enteritidis isolates were multidrug resistant. These results indicate the level of Salmonella contamination in duck farm environments in Korea is high. Good biosecurity and hygiene practices are the most effective measures for controlling Salmonella contamination.

Evaluation of Sampling Methods for the Study of Avian Respiratory Microbiota.

Although poultry microbiome discoveries are increasing due to the potential impact on poultry performance, studies examining the poultry respiratory microbiome are challenging because of the low microbial biomass and uniqueness of the avian respiratory tract, making it difficult to sample enough material for microbial analysis. Invasive sampling techniques requiring euthanasia are currently used to increase microbial mass for the analysis, thus making it impossible to sample individual birds longitudinally. In this study, we compared invasive (nasal wash, upper tracheal wash, lower tracheal wash, and lower respiratory lavage) and noninvasive (tracheal and choanal swabs) respiratory sampling techniques in two independent experiments by using 4-wk-old chickens. We first established the experimental baseline of respiratory microbiota by using invasive techniques to enable reasonable comparisons between sampling methods and between experiments. Although noninvasive sampling (live-bird swabs) resulted in lower 16S ribosomal RNA gene copy numbers compared with invasive sampling, live swabs were able to detect the dominant microbes captured by invasive techniques. Nevertheless, swabs from euthanatized birds were more reflective of the microbiota captured through invasive methods than live swab. Furthermore, from two separate experiments, we also demonstrated that respiratory microbiota sampling is highly reproducible, especially in the trachea and lower respiratory tract. Our study provides new insights and perspectives on decision making when sampling and studying poultry respiratory microbiota.

Dried SARS-CoV-2 virus maintains infectivity to Vero E6 cells for up to 48 h.

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is a great concern on both public and veterinary health. Multiple studies showed that the SARS-CoV-2 can persist for few days in wet condition, but it has not been clear whether the virus can maintain the infectivity in dry condition. Thus, we measured the infectious titer of dried SARS-CoV-2 (104 pfu/25 µL droplet) at 0, 0.5, 1, 2, 3, 24, and 48 h. Strikingly, the dried SARS-CoV-2 virus did not lose the infectivity to Vero E6 cells for up to 48 h. Our findings warrants that the drying cannot replace the surface disinfection to prevent transmission via common vehicle or nosocomial infection. Future studies can apply our experimental setting to test the efficacy of diverse disinfecting procedures.