Detection of porcine reproductive and respiratory syndrome virus (PRRSV)-specific IgM-IgA in oral fluid samples reveals PRRSV infection in the presence of maternal antibody

The ontogeny of PRRSV antibody in oral fluids has been described using isotype-specific ELISAs. Mirroring the serum response, IgM appears in oral fluid by 7 days post inoculation (DPI), IgA after 7 DPI, and IgG by 9 to 10 DPI. Commercial PRRSV ELISAs target the detection of IgG because the higher concentration of IgG relative to other isotypes provides the best diagnostic discrimination. Oral fluids are increasingly used for PRRSV surveillance in commercial herds, but in younger pigs, a positive ELISA result may be due either to maternal antibody or to antibody produced by the pigs in response to infection. To address this issue, a combined IgM-IgA PRRSV oral fluid ELISA was developed and evaluated for its capacity to detect pig-derived PRRSV antibody in the presence of maternal antibody. Two longitudinal studies were conducted. In Study 1 (modified-live PRRS vaccinated pigs), testing of individual pig oral fluid samples by isotype-specific ELISAs demonstrated that the combined IgM-IgA PRRSV ELISA provided better discrimination than individual IgM or IgA ELISAs. In Study 2 (field data), testing of pen-based oral fluid samples confirmed the findings in Study 1 and established that the IgM-IgA ELISA was able to detect antibody produced by pigs in response to wild-type PRRSV infection, despite the presence of maternal IgG. Overall, the combined PRRSV IgM-IgA oral fluid ELISA described in this study is a potential tool for PRRSV surveillance, particularly in populations of growing pigs originating from PRRSV-positive or vaccinated breeding herds

Pen-Based Swine Oral Fluid Samples Contain Both Environmental and Pig-Derived Targets

Laboratory methods for detecting specific pathogens in oral fluids are widely reported, but there is little research on the oral fluid sampling process itself. In this study, a fluorescent tracer (diluted red food coloring) was used to test the transfer of a target directly from pigs or indirectly from the environment to pen-based oral fluid samples. Pens of ~30, ~60, and ~125 14-week-old pigs (32 pens/size) on commercial swine farms received one of two treatments: (1) pig exposure, i.e., ~3.5 mL of tracer solution sprayed into the mouth of 10% of the pigs in the pen; (2) environmental exposure, i.e., 20 mL of tracer solution was poured on the floor in the center of the pen. Oral fluids collected one day prior to treatment (baseline fluorescence control) and immediately after treatment were tested for fluorescence. Data were evaluated by receiver operating characteristic (ROC) analysis, with Youden’s J statistic used to set a threshold. Pretreatment oral fluid samples with fluorescence responses above the ROC threshold were removed from further analysis (7 of 96 samples). Based on the ROC analyses, oral fluid samples from 78 of 89 pens (87.6%), contained red food coloring, including 43 of 47 (91.5%) pens receiving pig exposure and 35 of 42 (83.3%) pens receiving environmental exposure. Thus, oral fluid samples contain both pig-derived and environmental targets. This methodology provides a safe and quantifiable method to evaluate oral fluid sampling vis-à-vis pen behavior, pen size, sampling protocol, and target distribution in the pen

Effect of pooled tracheal sample testing on the probability of Mycoplasma hyopneumoniae detection.

Acknowledgements: We acknowledge Iowa State University Veterinary Diagnostic Laboratory molecular team, Karen Krueger, Allison Kolker, and Jessica Miller for sample processing and testing.Tracheal pooling for Mycoplasma hyopneumoniae (M. hyopneumoniae) DNA detection allows for decreased diagnostic cost, one of the main constraints in surveillance programs. The objectives of this study were to estimate the sensitivity of pooled-sample testing for the detection of M. hyopneumoniae in tracheal samples and to develop probability of M. hyopneumoniae detection estimates for tracheal samples pooled by 3, 5, and 10. A total of 48 M. hyopneumoniae PCR-positive field samples were pooled 3-, 5-, and 10-times using field M. hyopneumoniae DNA-negative samples and tested in triplicate. The sensitivity was estimated at 0.96 (95% credible interval [Cred. Int.]: 0.93, 0.98) for pools of 3, 0.95 (95% Cred. Int: 0.92, 0.98) for pools of 5, and 0.93 (95% Cred. Int.: 0.89, 0.96) for pools of 10. All pool sizes resulted in PCR-positive if the individual tracheal sample Ct value was < 33. Additionally, there was no significant decrease in the probability of detecting at least one M. hyopneumoniae-infected pig given any pool size (3, 5, or 10) of tracheal swabs. Furthermore, this manuscript applies the probability of detection estimates to various real-life diagnostic testing scenarios. Combining increased total animals sampled with pooling can be a cost-effective tool to maximize the performance of M. hyopneumoniae surveillance programs

Mycoplasma hyopneumoniae Surveillance in Pig Populations: Establishing Sampling Guidelines for Detection in Growing Pigs

Antemortem detection of Mycoplasma hyopneumoniae infection in swine production systems has relied on antibody testing, but the availability of tests based on DNA detection and novel diagnostic specimens, e.g., tracheal swabs and oral fluids, has the potential to improve M. hyopneumoniae surveillance. A field study was performed over a 14-week period during which 10 pigs in one pen at the center of a room with 1,250 6-week-old pigs housed in 46 pens were intratracheally inoculated with M. hyopneumoniae. Thereafter, one tracheal sample, four serum samples, and one oral fluid sample were collected from every pen at 2-week intervals. Tracheal and oral fluid samples were tested for M. hyopneumoniae DNA and serum samples for M. hyopneumoniae antibody. Test results were modeled using a hierarchical Bayesian model, based on a latent spatial piecewise exponential survival model, to estimate the probability of detection by within-pen prevalence, number of positive pens in the barn, sample allocation, sample size, and sample type over time. Analysis showed that tracheal samples provided the earliest detection, especially at large sample sizes. While serum samples are more commonly collected and are less expensive to test, high probability of detection estimates were only obtained 30 days postexposure at large sample sizes. In all scenarios, probability of detection estimates for oral fluids within 30 days were significantly lower than those for tracheal and serum samples. Ultimately, the choice of specimen type, sample number, and assay will depend on testing objectives and economics, but the estimates provided here will assist in the design of M. hyopneumoniae surveillance and monitoring programs for different situations.This article is published as Clavijo, Maria Jose, Dapeng Hu, Seth Krantz, Jean Paul Cano, Thairê Pereira Maróstica, Alexandra Henao-Diaz, Ana Paula S. Poeta Silva et al. "Mycoplasma hyopneumoniae surveillance in pig populations: establishing sampling guidelines for detection in growing pigs." Journal of Clinical Microbiology 59, no. 5 (2021): e03051-20. DOI: 10.1128/JCM.03051-20. Copyright 2021 Clavijo et al. Attribution 4.0 International (CC BY 4.0). Posted with permission

Dietary inflammatory index and mortality: a cohort longitudinal study in a Mediterranean area

22siBackground: Higher Dietary Inflammatory Index (DII®) scores are associated with increased morbidity and mortality. However, little is known about the effects of DII on mortality in Mediterranean countries. Therefore, in the present study, we aimed to investigate the potential association between DII scores and overall, cancer and cardiovascular disease (CVD) mortality in people living in a Mediterranean area. Methods: DII scores were calculated using a validated food-frequency questionnaire. DII scores were then categorised into tertiles. Mortality was ascertained via death certificates. The association between DII scores with overall and cause-specific mortality was assessed via a multivariable Cox's regression analysis and reported as hazard ratios (HRs) with their 95% confidence intervals (CIs). Results: The study included 1565 participants (mean age 65.5 years; females 44.7%). After a median follow-up of 12 years (2005–2017), 366 (23.4%) participants died. After adjusting for 17 potential confounders, people with higher DII scores had an increased risk of death compared to those in the lowest (most anti-inflammatory) tertile (HR = 1.38; 95% CI = 1.04–1.82 for the second tertile; HR = 1.38; 95% CI = 1.03–1.86 for the third tertile). Each 1 SD increase in DII score increased the risk of death by 13%. No association was found between DII scores and cancer or CVD death when considered separately. Conclusions: Higher DII scores were associated with a significantly higher mortality risk, whereas the association with cause-specific mortality was less clear. These findings highlight the potential importance of diet in modulating inflammation and preventing death.nonenoneVeronese N.; Cisternino A.M.; Shivappa N.; Hebert J.R.; Notarnicola M.; Reddavide R.; Inguaggiato R.; Guerra V.; Logroscino A.; Rotolo O.; Chiloiro M.; Leandro G.; De Leonardis G.; Tutino V.; Misciagna G.; Fontana L.; Caruso M.G.; Giampiero D.M.; Marisa N.; Osvaldo B.; Benedetta D.; Vittorio P.Veronese, N.; Cisternino, A. M.; Shivappa, N.; Hebert, J. R.; Notarnicola, M.; Reddavide, R.; Inguaggiato, R.; Guerra, V.; Logroscino, A.; Rotolo, O.; Chiloiro, M.; Leandro, G.; De Leonardis, G.; Tutino, V.; Misciagna, G.; Fontana, L.; Caruso, M. G.; Giampiero, D. M.; Marisa, N.; Osvaldo, B.; Ducceschi, Benedetta; Vittorio, P