Internal reference genes with the potential for normalizing quantitative PCR results for oral fluid specimens.

In basic research, testing of oral fluid specimens by real-time quantitative polymerase chain reaction (qPCR) has been used to evaluate changes in gene expression levels following experimental treatments. In diagnostic medicine, qPCR has been used to detect DNA/RNA transcripts indicative of bacterial or viral infections. Normalization of qPCR using endogenous and exogenous reference genes is a well-established strategy for ensuring result comparability by controlling sample-to-sample variation introduced during sampling, storage, and qPCR testing. In this review, the majority of recent publications in human (n = 136) and veterinary (n = 179) medicine did not describe the use of internal reference genes in qPCRs for oral fluid specimens (52.9% animal studies; 57.0% human studies). However, the use of endogenous reference genes has not been fully explored or validated for oral fluid specimens. The lack of valid internal reference genes inherent to the oral fluid matrix will continue to hamper the reliability, reproducibility, and generalizability of oral fluid qPCR assays until this issue is addressed.

What Should I do and Who's to blame? A cross-national study on youth's attitudes and beliefs in times of COVID-19.

The COVID-19 crisis has had a major impact on youth. This study examined factors associated with youth's attitudes towards their government's response to the pandemic and their blaming of individuals from certain risk groups, ethnic backgrounds, and countries or regions. In a sample of 5,682 young adults (Mage = 22) from 14 countries, lower perceived burden due to COVID-19, more collectivistic and less individualistic values, and more empathy were associated with more positive attitudes towards the government and less blaming of individuals of certain groups. Youth's social identification with others in the pandemic mediated these associations in the same direction, apart from the COVID-19 burden on attitudes, which had a positive indirect effect. No evidence of country-level moderation was found.

The N-terminal Subunit of the Porcine Deltacoronavirus Spike Recombinant Protein (S1) Does Not Serologically Cross-react with Other Porcine Coronaviruses.

Porcine deltacoronavirus (PDCoV), belonging to family Coronaviridae and genus Deltacoronavirus, is a major enteric pathogen in swine. Accurate PDCoV diagnosis relying on laboratory testing and antibody detection is an important approach. This study evaluated the potential of the receptor-binding subunit of the PDCoV spike protein (S1), generated using a mammalian expression system, for specific antibody detection via indirect enzyme-linked immunosorbent assay (ELISA). Serum samples were collected at day post-inoculation (DPI) -7 to 42, from pigs (n = 83) experimentally inoculated with different porcine coronaviruses (PorCoV). The diagnostic sensitivity of the PDCoV S1-based ELISA was evaluated using serum samples (n = 72) from PDCoV-inoculated animals. The diagnostic specificity and potential cross-reactivity of the assay was evaluated on PorCoV-negative samples (n = 345) and samples collected from pigs experimentally inoculated with other PorCoVs (n = 472). The overall diagnostic performance, time of detection, and detection rate over time varied across different S/P cut-offs, estimated by Receiver Operating Characteristic (ROC) curve analysis. The higher detection rate in the PDCoV group was observed after DPI 21. An S/P cut-off of 0.25 provided 100% specificity with no serological cross-reactivity against other PorCoV. These results support the use of S1 protein-based ELISA for accurate detection of PDCoV infections, transference of maternal antibodies, or active surveillance.

A longitudinal study on PRRSV detection in swine herds with different demographics and PRRSV management strategies.

Porcine reproductive and respiratory syndrome virus (PRRSV) has been one of the major health-related concerns in the swine production industry. Through its rapid transmission and mutation, the simultaneous circulation of multiple PRRSV strains can be a challenge in PRRSV diagnostic, control and surveillance. The objective of this longitudinal study was to describe the temporal detection of PRRSV in swine farms with different production types and PRRS management strategies. Tonsil scraping (n = 344) samples were collected from three breeding and two growing herds for approximately one year. In addition, processing fluids (n = 216) were obtained from piglet processing batches within the three breeding farms while pen-based oral fluids (n = 125) were collected in the two growing pig farms. Viral RNA extraction and reverse-transcription quantitative PCR (RT-qPCR) were conducted for all samples. The sample positivity threshold was set at quantification cycle (Cq) of ≤ 37. Statistical analyses were performed using generalized linear modelling and post hoc pairwise comparisons with Bonferroni adjustments using R statistical software. The results suggested a higher probability of detection in processing fluids compared to tonsil scraping specimens [odds ratio (OR) = 3.86; p = .096] in breeding farms whereas oral fluids were outperformed by tonsil scrapings (OR = 0.26; p < .01) in growing pig farms. The results described herein may lead to an improvement in PRRSV diagnostic and surveillance by selecting proper specimens.

Evaluation of a Water-Based Medium-Expansion Foam Depopulation Method in Suckling and Finisher Pigs.

The threat of foreign animal disease introduction through contaminated animal products, feed ingredients, and wildlife vectors have highlighted the need for additional approved methods for mass depopulation of swine under emergency scenarios, especially methods that can be applied to pigs across all production phases. The market disruption within the swine industry due to the SARS-CoV-2 pandemic has demonstrated this lack of preparation. The objective of this study was to validate water-based foam as a mass depopulation method for suckling (18 to 24 days of age) and finisher stage (63 to 100 days of age) pigs. Finisher pigs (n = 31, originally 32 but one finisher pig died prior to foaming), allocated as 9 triads and 1 set of 4 pigs, in 10 total replicates, and suckling pigs (n = 32), randomly allocated to two replicates, were completely covered in water-based medium-expansion foam for a 15-min dwell time in a bulk container. Container fill time for the trials were 6.5 ± 0.68 s and 5.3 ± 0.03 s for finisher and suckling pig replicates, respectively. Average (± SD) time for cessation of movement was 105 ± 39.1 s (s) for finisher pigs and 79.5 ± 10.5 s for suckling pigs. After completion of the 15-min dwell time in the foam, all pigs were confirmed dead upon removal from the container. The results from the present study suggest that the use of water-based foam can be an effective means of mass depopulation for suckling and finisher stage pigs, supporting previous research on the application to adult swine.