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Stadler J, Zwickl S, Gumbert S, Ritzmann M, Lillie-Jaschniski K, Harder T, Graaf-Rau A, Skampardonis V, Eddicks M. Influenza surveillance in pigs: balancing act between broad diagnostic coverage and specific virus characterization. Porcine Health Manag 2024; 10:19. [PMID: 38764074 PMCID: PMC11104006 DOI: 10.1186/s40813-024-00367-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 03/28/2024] [Indexed: 05/21/2024] Open
Abstract
BACKGROUND Monitoring of infectious diseases on swine farms requires a high diagnostic sensitivity and specificity of the test system. Moreover, particularly in cases of swine influenza A virus (swIAV) it is desirable to include characterization of the virus as precisely as possible. This is indispensable for strategies concerning prophylaxis of swIAV and furthermore, to meet the requirements of a purposeful monitoring of newly emerging swIAV strains in terms of vaccine design and public health. Within the present cross-sectional study, we compared the diagnostic value of group samples (wipes of surfaces with direct contact to mouth/nose, dust wipes, udder skin wipes, oral fluids) to individual samples (nasal swabs, tracheobronchial swabs) for both swIAV identification and characterization. Sampling included different stages of pig production on 25 sow farms with attached nursery considered as enzootically infected with swIAV. Firstly, samples were analyzed for IAV genome and subsequently samples with Ct-values < 32 were subtyped by multiplex RT-qPCR. RESULTS Nasal swabs of suckling piglets and nursery pigs resulted in a higher odds to detect swIAV (p < 0.001) and to identify swIAV subtypes by RT-qPCR (p < 0.05) compared to nasal swabs of sows. In suckling piglets, significant higher rates of swIAV detection could be observed for nasal swabs (p = 0.007) and sow udder skin wipes (p = 0.036) compared to contact wipes. In the nursery, group sampling specimens were significantly more often swIAV positive compared to individual samples (p < 0.01), with exception of the comparison between contact wipes and nasal swabs (p = 0.181). However, in general nasal swabs were more likely to have Ct-value < 32 and thus, to be suitable for subtyping by RT-qPCR compared to dust wipes, contact wipes, udder skin wipes and tracheobronchial swabs (p < 0.05). Interestingly, different subtypes were found in different age groups as well as in different specimens in the same holding. CONCLUSION Although population-based specimens are highly effective for swIAV monitoring, nasal swabs are still the preferable sampling material for the surveillance of on-farm circulating strains due to significantly higher virus loads. Remarkably, sampling strategies should incorporate suckling piglets and different age groups within the nursery to cover as many as possible of the on-farm circulating strains.
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Affiliation(s)
- Julia Stadler
- Clinic for Swine, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität München, Oberschleißheim, Germany.
| | - Sophia Zwickl
- Clinic for Swine, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität München, Oberschleißheim, Germany
| | - Sophie Gumbert
- Clinic for Swine, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität München, Oberschleißheim, Germany
| | - Mathias Ritzmann
- Clinic for Swine, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität München, Oberschleißheim, Germany
| | | | - Timm Harder
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Annika Graaf-Rau
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Vassilis Skampardonis
- Department of Epidemiology, Biostatistics and Economics of Animal Production, School of Veterinary Medicine, University of Thessaly, 43132, Karditsa, Greece
| | - Matthias Eddicks
- Clinic for Swine, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität München, Oberschleißheim, Germany
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Armenta-Leyva B, Munguía-Ramírez B, Cheng TY, Ye F, Henao-Díaz A, Giménez-Lirola LG, Zimmerman J. Normalizing real-time PCR results in routine testing. J Vet Diagn Invest 2024; 36:78-85. [PMID: 37919959 PMCID: PMC10734596 DOI: 10.1177/10406387231206080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023] Open
Abstract
Normalization, the process of controlling for normal variation in sampling and testing, can be achieved in real-time PCR assays by converting sample quantification cycles (Cqs) to "efficiency standardized Cqs" (ECqs). We calculated ECqs as E-ΔCq, where E is amplification efficiency and ΔCq is the difference between sample and reference standard Cqs. To apply this approach to a commercial porcine reproductive and respiratory syndrome virus (PRRSV) RT-qPCR assay, we created reference standards by rehydrating and then diluting (1 × 10-4) a PRRSV modified-live vaccine (PRRS MLV; Ingelvac) with serum or oral fluid (OF) to match the sample matrix to be tested. Sample ECqs were calculated using the mean E and reference standard Cq calculated from the 4 reference standards on each plate. Serum (n = 132) and OF (n = 130) samples were collected from each of 12 pigs vaccinated with a PRRSV MLV from -7 to 42 d post-vaccination, tested, and sample Cqs converted to ECqs. Mean plate Es were 1.75-2.6 for serum and 1.7-2.3 for OF. Mean plate reference standard Cqs were 29.1-31.3 for serum and 29.2-31.5 for OFs. Receiver operating characteristic analysis calculated the area under the curve for serum and OF sample ECqs as 0.999 (95% CI: 0.997, 1.000) and 0.947 (0.890, 1.000), respectively. For serum, diagnostic sensitivity and specificity of the commercial PRRSV RT-qPCR assay were estimated as 97.9% and 100% at an ECq cutoff ≥ 0.20, and for OF, 82.6% and 100%, respectively, at an ECq cutoff ≥ 0.45.
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Affiliation(s)
- Betsy Armenta-Leyva
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Lloyd Veterinary Medical Center, Iowa State University, Ames, IA, USA
| | - Berenice Munguía-Ramírez
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Lloyd Veterinary Medical Center, Iowa State University, Ames, IA, USA
| | - Ting-Yu Cheng
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, the Ohio State University, Columbus, OH, USA
| | - Fangshu Ye
- Department of Statistics, College of Liberal Arts and Sciences, Iowa State University, Ames, IA, USA
| | | | - Luis G. Giménez-Lirola
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Lloyd Veterinary Medical Center, Iowa State University, Ames, IA, USA
| | - Jeffrey Zimmerman
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Lloyd Veterinary Medical Center, Iowa State University, Ames, IA, USA
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3
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Pang J, Ju W, Welch M, Gauger P, Liu P, Zhang Q, Wang C. Nonparametric bootstrap methods for interval estimation of the area under the ROC curve with correlated diagnostic test data: application to whole-virus ELISA testing in swine. Front Vet Sci 2023; 10:1274786. [PMID: 38116513 PMCID: PMC10728486 DOI: 10.3389/fvets.2023.1274786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 11/22/2023] [Indexed: 12/21/2023] Open
Abstract
Developing and evaluating novel diagnostic assays are crucial components of contemporary diagnostic research. The receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC) are frequently used to evaluate diagnostic assays' performance. The variation in AUC estimation can be quantified nonparametrically using resampling methods, such as bootstrapping, and then used to construct interval estimation for the AUC. When multiple observations are observed from the same subject, which is very common in veterinary diagnostic tests evaluation experiments, a traditional bootstrap-based method can fail to provide valid interval estimations of AUC. In particular, the traditional method does not account for the correlation among data observations and could result in interval estimation that fails to cover the true AUC adequately at the desired confidence level. In this paper, we proposed two novel methods to calculate the confidence interval of the AUC for correlated diagnostic test data based on cluster bootstrapping and hierarchical bootstrapping, respectively. Our simulation studies showed that both proposed methods had adequate coverage probabilities which were higher than the existing traditional method when there were intra-subject correlations. We also discussed applying the proposed methods to evaluate a novel whole-virus ELISA (wv-ELISA) diagnostic assay in detecting porcine parainfluenza virus type-1 antibodies in swine serum.
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Affiliation(s)
- Jinji Pang
- Department of Statistics, Iowa State University, Ames, IA, United States
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States
| | - Wangqian Ju
- Department of Statistics, Iowa State University, Ames, IA, United States
| | - Michael Welch
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, United States
| | - Phillip Gauger
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, United States
| | - Peng Liu
- Department of Statistics, Iowa State University, Ames, IA, United States
| | - Qijing Zhang
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States
| | - Chong Wang
- Department of Statistics, Iowa State University, Ames, IA, United States
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, United States
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4
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Munguía-Ramírez B, Armenta-Leyva B, Henao-Díaz A, Cheng TY, Zhang J, Rawal G, Ye F, Giménez-Lirola L, Zimmerman JJ. Effect of extrinsic factors on the detection of PRRSV and a porcine-specific internal sample control in serum, oral fluid, and fecal specimens tested by RT-rtPCR. J Vet Diagn Invest 2023; 35:374-383. [PMID: 37166086 PMCID: PMC10331379 DOI: 10.1177/10406387231174556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023] Open
Abstract
We characterized the effect of 1) temperature × time, 2) freeze-thaw cycles, and 3) high porcine reproductive and respiratory syndrome virus (PRRSV) RNA concentrations on the detection of PRRSV and a porcine-specific internal sample control (ISC) in serum, oral fluid, and fecal samples using a commercial PRRSV RT-rtPCR assay (Idexx). In study 1, the effect of temperature × time on PRRSV and ISC detection was shown to be specimen dependent. In serum stored at 4, 10, or 20°C, PRRSV detection was consistent for up to 168 h, but storage at 30°C reduced detectable PRRSV RNA. ISC RNA was stable in serum held at 4 and 10°C, but not at 20 and 30°C. In contrast, PRRSV and ISC RNAs in oral fluid and fecal samples continuously decreased at all temperature × time treatments. Based on these data, serum samples should be stored at ≤ 20°C to optimize PRRSV RNA detection. Oral fluid and fecal samples should be frozen in a non-self-defrosting freezer until tested. In study 2, freeze-thaw cycles had little impact on PRRSV and ISC detection, but more so in oral fluids than serum or fecal samples. Thus, freeze-thaw cycles in oral fluids should be minimized before RT-rtPCR testing. In study 3, the ISC was not affected by high concentrations of PRRSV RNA in serum, oral fluid, or fecal samples. It should not be assumed that data from our PRRSV study are applicable to other pathogens; additional pathogen-specific studies are required.
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Affiliation(s)
- Berenice Munguía-Ramírez
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Betsy Armenta-Leyva
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | | | - Ting-Yu Cheng
- Department of Veterinary Preventive Medicine, The Ohio State University, Columbus, OH, USA
| | - Jianqiang Zhang
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Gaurav Rawal
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Fangshu Ye
- Department of Statistics, College of Liberal Arts and Sciences, Iowa State University, Ames, IA, USA
| | - Luis Giménez-Lirola
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Jeffrey J. Zimmerman
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
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5
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Munguía-Ramírez B, Armenta-Leyva B, Henao-Díaz A, Ye F, Baum DH, Giménez-Lirola LG, Zimmerman JJ. Evaluation of a Porcine Endogenous Reference Gene (Internal Sample Control) in a Porcine Reproductive and Respiratory Syndrome Virus RT-qPCR. Vet Sci 2023; 10:381. [PMID: 37368767 DOI: 10.3390/vetsci10060381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/29/2023] [Accepted: 05/30/2023] [Indexed: 06/29/2023] Open
Abstract
Endogenous reference genes are used in gene-expression studies to "normalize" the results and, increasingly, as internal sample controls (ISC) in diagnostic quantitative polymerase chain reaction (qPCR). Three studies were conducted to evaluate the performance of a porcine-specific ISC in a commercial porcine reproductive and respiratory syndrome virus (PRRSV) reverse transcription-qPCR. Study 1 evaluated the species specificity of the ISC by testing serum from seven non-porcine domestic species (n = 34). In Study 2, the constancy of ISC detection over time (≥42 days) was assessed in oral fluid (n = 130), serum (n = 215), and feces (n = 132) collected from individual pigs of known PRRSV status. In Study 3, serum (n = 150), oral fluid (n = 150), and fecal samples (n = 75 feces, 75 fecal swabs) from commercial herds were used to establish ISC reference limits. Study 1 showed that the ISC was porcine-specific, i.e., all samples from non-porcine species were ISC negative (n = 34). In Study 2, the ISC was detected in all oral fluid, serum, and fecal samples, but differed in concentration between specimens (p < 0.05; mixed-effects regression model). The results of Study 3 were used to establish ISC reference limits for the 5th, 2.5th and 1.25th percentiles. Overall, the ISC response was consistent to the point that failure in detection is sufficient justification for re-testing and/or re-sampling.
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Affiliation(s)
- Berenice Munguía-Ramírez
- Veterinary Diagnostic and Production Animal Medicine Department, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Betsy Armenta-Leyva
- Veterinary Diagnostic and Production Animal Medicine Department, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Alexandra Henao-Díaz
- Pig Improvement Company (PIC) México, Santiago de Querétaro 76040, Querétaro, Mexico
| | - Fangshu Ye
- Department of Statistics, College of Liberal Arts and Sciences, Iowa State University, Ames, IA 50011, USA
| | - David H Baum
- Veterinary Diagnostic and Production Animal Medicine Department, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Luis G Giménez-Lirola
- Veterinary Diagnostic and Production Animal Medicine Department, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Jeffrey J Zimmerman
- Veterinary Diagnostic and Production Animal Medicine Department, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
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6
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Xie CZ, Tao YM, Ha Z, Zhang P, Zhang Y, Zhang H, Jin NY, Lu HJ. Characterization of a new NSP2-deletion NADC34-Like Porcine Reproductive and Respiratory Syndrome Virus in China. Res Vet Sci 2022; 152:212-218. [PMID: 35998397 DOI: 10.1016/j.rvsc.2022.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 06/29/2022] [Accepted: 08/03/2022] [Indexed: 11/30/2022]
Abstract
Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is the causative agent of Porcine Reproductive and Respiratory Syndrome (PRRS), which has caused huge economic losses to the pig industry worldwide. PRRSV NADC34-Like PRRSV 2020-Acheng-1 strain, which caused high morbidity and high mortality were isolated from dead piglets (high-throughput sequencing to show that only PRRSV and TGEV) on a farm in northeastern China. The full-length genome sequence of 2020-Acheng-1 shares 95.6% nucleotide homology with NADC34 PRRSV without any gene insertion, but has a unique 17 amino acid (469aa to 486aa) deletion in Nsp2 compared with all NADC34-Like strains in NCBI and there are unique 100 amino acid deletions. In addition, difference degree of changes in signal peptide, trans-membrane region (TM), main neutralizing epitope (PNE), non-neutralizing epitope and N-glycosylation site were observed in GP5 of 2020-Acheng-1 and other PRRSV-2 strains, we only found a change in the fifteenth amino acid of signal peptide of in GP5 of 2020-Acheng-1 with NADC34 strains. Recombination analysis showed that 2020-Acheng-1 strain did not have any recombination events with representative PRRSV-2 strains in China. This study provided valuable evidence for understanding the role of NADC34-Like strain that impact on pathogenicity.
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Affiliation(s)
- Chang-Zhan Xie
- Chinese Academy of Agricultural Sciences, Changchun Veterinary Research Institute, Changchun, China
| | - Yi-Mo Tao
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Zhuo Ha
- Chinese Academy of Agricultural Sciences, Changchun Veterinary Research Institute, Changchun, China
| | - Ping Zhang
- Institute of specialty, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Ying Zhang
- College of Veterinary Medicine, College of Animal Science, Jilin University, Changchun 130062, China
| | - He Zhang
- Chinese Academy of Agricultural Sciences, Changchun Veterinary Research Institute, Changchun, China
| | - Ning-Yi Jin
- Chinese Academy of Agricultural Sciences, Changchun Veterinary Research Institute, Changchun, China; College of Animal Science and Technology, Guangxi University, Nanning, China; College of Veterinary Medicine, College of Animal Science, Jilin University, Changchun 130062, China; Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, China.
| | - Hui-Jun Lu
- Chinese Academy of Agricultural Sciences, Changchun Veterinary Research Institute, Changchun, China; College of Animal Science and Technology, Guangxi University, Nanning, China; College of Veterinary Medicine, College of Animal Science, Jilin University, Changchun 130062, China; Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, China.
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7
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Schoneberg C, Böttcher J, Janowetz B, Rostalski A, Kreienbrock L, Campe A. An intercomparison study of ELISAs for the detection of porcine reproductive and respiratory syndrome virus – evaluating six conditionally dependent tests. PLoS One 2022; 17:e0262944. [PMID: 35077518 PMCID: PMC8789123 DOI: 10.1371/journal.pone.0262944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 01/08/2022] [Indexed: 11/18/2022] Open
Abstract
Latent class analysis is a widely used statistical method for evaluating diagnostic tests without any gold standard. It requires the results of at least two tests applied to the same individuals. Based on the resulting response patterns, the method estimates the test accuracy and the unknown disease status for all individuals in the sample. An important assumption is the conditional independence of the tests. If tests with the same biological principle are used, the assumption is not fulfilled, which may lead to biased results. In a recent publication, we developed a method that considers the dependencies in the latent class model and estimates all parameters using frequentist methods. Here, we evaluate the practicability of the method by applying it to the results of six ELISA tests for antibodies against the porcine reproductive and respiratory syndrome (PRRS) virus in pigs that generally follow the same biological principle. First, we present different methods of identifying suitable starting values for the algorithm and apply these to the dataset and a vaccinated subgroup. We present the calculated values of the test accuracies, the estimated proportion of antibody-positive animals and the dependency structure for both datasets. Different starting values led to matching results for the entire dataset. For the vaccinated subgroup, the results were more dependent on the selected starting values. All six ELISA tests are well suited to detect antibodies against PRRS virus, whereas none of the tests had the best values for sensitivity and specificity simultaneously. The results thus show that the method used is able to determine the parameter values of conditionally dependent tests with suitable starting values. The choice of test should be based on the general fit-for-purpose concept and the population under study.
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Affiliation(s)
- Clara Schoneberg
- Department of Biometry, Epidemiology and Information Processing, WHO Collaborating Centre for Research and Training for Health in the Human-Animal-Environment Interface, University for Veterinary Medicine Hannover, Hannover, Germany
- * E-mail:
| | | | | | | | - Lothar Kreienbrock
- Department of Biometry, Epidemiology and Information Processing, WHO Collaborating Centre for Research and Training for Health in the Human-Animal-Environment Interface, University for Veterinary Medicine Hannover, Hannover, Germany
| | - Amely Campe
- Department of Biometry, Epidemiology and Information Processing, WHO Collaborating Centre for Research and Training for Health in the Human-Animal-Environment Interface, University for Veterinary Medicine Hannover, Hannover, Germany
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8
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Ortega J, Infantes-Lorenzo JA, Bezos J, Roy Á, de Juan L, Romero B, Moreno I, Gómez-Buendía A, Agulló-Ros I, Domínguez L, Domínguez M. Evaluation of P22 ELISA for the Detection of Mycobacterium bovis-Specific Antibody in the Oral Fluid of Goats. Front Vet Sci 2021; 8:674636. [PMID: 34458351 PMCID: PMC8385241 DOI: 10.3389/fvets.2021.674636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 07/20/2021] [Indexed: 11/13/2022] Open
Abstract
The ante-mortem diagnosis of tuberculosis (TB) in ruminants is based mainly on the intradermal tuberculin test and the IFN-γ assay. Antibody (Ab)-based tests have emerged as potential tools for the detection of TB infected animals using serum, plasma, or even milk samples. Oral fluids have also been evaluated as alternative samples with which to detect specific Abs against Mycobacterium bovis in pigs or wild boars, but not in ruminants. The objective of this study was, therefore, to evaluate the performance of an in house-ELISA for TB diagnosis (P22 ELISA) in goats as an experimental model for the diagnosis of TB using oral fluid samples. Oral fluid samples from 64 goats from a TB-infected herd (n = 197) and all the animals from a TB-free herd (n = 113) were analyzed using the P22 ELISA. The estimated sensitivity (Se) and specificity (Sp) were 34.4% (95% CI: 22.4–45.6) and 100% (95% CI: 97.4–100), respectively. The optimal cut-off point was set at 100% according to the ROC analysis. Those animals with a higher level of Abs in their oral fluid attained a higher lesion score (p = 0.018). In fact, when taking into account only the setting of the animals with severe lesions (n = 16), the ELISA showed a Se of 75% (95% CI: 53.7–96.2). Results of the present study suggest that the P22 ELISA is highly specific but has a limited value detecting infected animals in oral fluid samples. Nevertheless, its performance is significantly higher in the presence of severe lesions.
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Affiliation(s)
- Javier Ortega
- VISAVET Health Surveillance Centre, Complutense University of Madrid, Madrid, Spain.,Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| | - José A Infantes-Lorenzo
- Unidad de Inmunología Microbiana, Centro Nacional de Microbiología, Instituto de Investigación Carlos III, Madrid, Spain
| | - Javier Bezos
- VISAVET Health Surveillance Centre, Complutense University of Madrid, Madrid, Spain.,Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| | - Álvaro Roy
- VISAVET Health Surveillance Centre, Complutense University of Madrid, Madrid, Spain
| | - Lucia de Juan
- VISAVET Health Surveillance Centre, Complutense University of Madrid, Madrid, Spain.,Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| | - Beatriz Romero
- VISAVET Health Surveillance Centre, Complutense University of Madrid, Madrid, Spain
| | - Inmaculada Moreno
- Unidad de Inmunología Microbiana, Centro Nacional de Microbiología, Instituto de Investigación Carlos III, Madrid, Spain
| | | | - Irene Agulló-Ros
- Grupo de Investigación en Sanidad Animal y Zoonosis, Departamento de Anatomía y Anatomía Patológica Comparadas, Facultad de Veterinaria, Universidad de Córdoba, Córdoba, Spain
| | - Lucas Domínguez
- VISAVET Health Surveillance Centre, Complutense University of Madrid, Madrid, Spain.,Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| | - Mercedes Domínguez
- Unidad de Inmunología Microbiana, Centro Nacional de Microbiología, Instituto de Investigación Carlos III, Madrid, Spain
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9
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Gava D, Caron L, Schaefer R, Silva VS, Weiblen R, Flores EF, de Lima M, Takeda GZ, Ciacci-Zanella JR. A retrospective study of porcine reproductive and respiratory syndrome virus infection in Brazilian pigs from 2008 to 2020. Transbound Emerg Dis 2021; 69:903-907. [PMID: 33590723 DOI: 10.1111/tbed.14036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 11/29/2022]
Abstract
Porcine reproductive and respiratory syndrome (PRRS) is a viral disease characterized by reproductive impairment or failure in breeding animals, and a respiratory disease in pigs of any age. Brazil is the fourth largest pork producer and exporter globally, and PRRS virus (PRRSV) infection has never been reported in the country. This study aimed to investigate the status of porcine biological samples from commercial swine herds, quarantined imported boars, wild boars and feral pigs to update PRRS information in Brazil. A total of 14,382 samples were collected from 2008 to 2020, including sera (n = 12,841), plasma (n = 1,000) and oral fluids (n = 541), comprehending 137 herds and free-living pigs in eight Brazilian states. One out of 1,000 (0.1%) plasma and 15 out of 12,841 (0.11%) serum samples tested positive for PRRSV antibodies through ELISA. Upon ELISA retesting, only the plasma sample, from one 8-day-old piglet remained positive. All sixteen previously PRRSV antibody-positive samples were tested through RT-PCR and found to be negative. The presence of false-positive or singleton reactors are quite expected. Thus, the use of different/alternative diagnostic tests is indicated for an efficient PRRSV detection. Taken together, our findings demonstrated no conclusive evidence of PRRSV infection in the tested pigs, highlighting the importance to reinforce the surveillance program to prevent the introduction and eventual dissemination of PRRSV in Brazil.
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Affiliation(s)
| | | | | | | | - Rudi Weiblen
- Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Eduardo Furtado Flores
- Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Marcelo de Lima
- Faculdade de Veterinária, Universidade Federal de Pelotas, Pelotas, Brazil
| | - Guilherme Zaha Takeda
- Chefe da Divisão de Sanidade dos Suídeos/CAT/CGSA/DSA/DAS, Ministério da Agricultura, Pecuária e Abastecimento, Brasîlia, Brazil
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10
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Henao-Diaz A, Zhang M, Giménez-Lirola L, Ramirez E, Gauger P, Baum DH, Clavijo MJ, Rotolo M, Main RG, Zimmerman J. Adapting a porcine reproductive and respiratory syndrome virus (PRRSV) oral fluid antibody ELISA to routine surveillance. Prev Vet Med 2021; 188:105250. [PMID: 33429134 DOI: 10.1016/j.prevetmed.2020.105250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 12/20/2020] [Accepted: 12/21/2020] [Indexed: 10/22/2022]
Abstract
Distinct from tests used in diagnostics, tests used in surveillance must provide for detection while avoiding false alarms, i.e., acceptable diagnostic sensitivity but high diagnostic specificity. In the case of the reproductive and respiratory syndrome virus (PRRSV), RNA detection meets these requirements during the period of viremia, but antibody detection better meets these requirements in the post-viremic stage of the infection. Using the manufacturer's recommended cut-off (S/P ≥ 0.4), the diagnostic specificity of a PRRSV oral fluid antibody ELISA (IDEXX Laboratories, Inc., Westbrook, ME, USA) evaluated in this study was previously reported as ≥ 97 %. The aim of this study was to improve its use in surveillance by identifying a cut-off that would increase diagnostic specificity yet minimally impact its diagnostic sensitivity. Three sample sets were used to achieve this goal: oral fluids (n = 596) from pigs vaccinated with a modified live PRRSV vaccine under experimental conditions, field oral fluids (n = 1574) from 94 production sites of known negative status, and field oral fluids (n = 1380) from 211 sites of unknown PRRSV status. Based on the analysis of samples of known status (experimental samples and field samples from negative sites), a cut-off of S/P ≥ 1.0 resulted in a diagnostic specificity of 99.2 (95 % CI: 98.8, 99.7) and a diagnostic sensitivity of 96.5 (95 % CI: 85.2, 99.2). Among 211 sites of unknown status, 81 sites were classified as antibody positive using the manufacturer's cut-off; 20 of which were reclassified as negative using a cut-off of S/P ≥ 1.0. Further analysis showed that these 20 sites had a small proportion of samples (18.0 %) with S/P values just exceeding the manufacturer's cut-off (x̄ = 0.5). Whereas the remainder of positive sites (n = 61) had a high proportion of samples (76.3 %) with high S/P values (x̄ = 6.6). Thus, the manufacturer's cut-off (S/P ≥ 0.4) is appropriate for diagnostic applications, but a cut-off of S/P ≥ 1.0 provided the higher specificity required for surveillance. A previously unreported finding in this study was a statistically significant association between unexpected reactors and specific production sites and animal ages or stages. While beyond the scope of this study, these data suggested that certain animal husbandry or production practices may be associated with non-specific reactions.
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Affiliation(s)
- Alexandra Henao-Diaz
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Min Zhang
- Department of Statistics, College of Liberal Arts and Sciences, Iowa State University, Ames, IA, 50011, USA
| | - Luis Giménez-Lirola
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Esteban Ramirez
- Grupo Porcícola Mexicano Kekén. Mérida, Yucatán, 97100, Mexico
| | - Phil Gauger
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - David H Baum
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Maria J Clavijo
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA; PIC North America, 100 Bluegrass Commons Blvd. Ste. 2200, Hendersonville, TN, 37075, USA
| | - Marisa Rotolo
- PIC North America, 100 Bluegrass Commons Blvd. Ste. 2200, Hendersonville, TN, 37075, USA
| | - Rodger G Main
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Jeffrey Zimmerman
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA.
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11
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Zou Y, Li S, Ngai T, Zhang S, Ma G, Wu J. Green preparation of hydrogel particles-in-emulsions for simultaneous enhancement of humoral and cell-mediated immunity. Eng Life Sci 2020; 20:514-524. [PMID: 33204238 PMCID: PMC7645649 DOI: 10.1002/elsc.202000011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 08/07/2020] [Accepted: 09/09/2020] [Indexed: 01/07/2023] Open
Abstract
Emulsions are one of the most often used vaccine adjuvant formulations. Although they promote high humoral immunity, the induced cellular immunity is often poor, which restrict their application. To enhance the cellular immunity, some researchers have prepared mixed formulations by adding particles into the aqueous phase of emulsions. However, the particle preparation process usually involves the addition and removal of organic reagents, which is environmentally unfriendly and cumbersome. Moreover, the obtained vaccine adjuvant only induces limited cell-mediated immunity and humoral immunity compared with emulsion-adjuvanted vaccines. Herein, we developed a green and simple method for fabricating a novel nanoparticles-in-emulsions (NPE) formulation. Firstly, a temperature-sensitive hydrogel was used to prepare particles by self-solidification without additional crosslinking reagents. Secondly, the white oil was used as organic phase to avoid the particle washing procedures and organic solvent residues. Moreover, the effect of NPE as vaccine adjuvant was evaluated by using two veterinary vaccines as model antigens. NPE showed advantages than the conventional vaccine formulations in inducing both humoral and cellular immunity. This work provides a facile and broadly applicable approach for preparing nanoparticles-in-emulsions formulation, and presents an effective adjuvant for enhancing immunity against infectious diseases.
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Affiliation(s)
- Yongjuan Zou
- State Key Laboratory of Biochemical Engineering, Institute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
- School of Chemical EngineeringUniversity of Chinese Academy of SciencesBeijingP. R. China
| | - Shuai Li
- State Key Laboratory of Biochemical Engineering, Institute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
- School of Chemical EngineeringUniversity of Chinese Academy of SciencesBeijingP. R. China
| | - To Ngai
- Department of ChemistryThe Chinese University of Hong KongShatinNTHong Kong
| | - Songping Zhang
- State Key Laboratory of Biochemical Engineering, Institute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
- School of Chemical EngineeringUniversity of Chinese Academy of SciencesBeijingP. R. China
| | - Guanghui Ma
- State Key Laboratory of Biochemical Engineering, Institute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
- School of Chemical EngineeringUniversity of Chinese Academy of SciencesBeijingP. R. China
- PLA Key Laboratory of Biopharmaceutical Production and Formulation EngineeringInstitute of Process Engineering, Chinese Academy of SciencesBeijingP. R. China
- Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjingP. R. China
| | - Jie Wu
- State Key Laboratory of Biochemical Engineering, Institute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
- School of Chemical EngineeringUniversity of Chinese Academy of SciencesBeijingP. R. China
- PLA Key Laboratory of Biopharmaceutical Production and Formulation EngineeringInstitute of Process Engineering, Chinese Academy of SciencesBeijingP. R. China
- Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjingP. R. China
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12
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Henao-Diaz A, Giménez-Lirola L, Baum DH, Zimmerman J. Guidelines for oral fluid-based surveillance of viral pathogens in swine. Porcine Health Manag 2020; 6:28. [PMID: 33082999 PMCID: PMC7569198 DOI: 10.1186/s40813-020-00168-w] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/26/2020] [Indexed: 12/18/2022] Open
Abstract
Recent decades have seen both rapid growth and extensive consolidation in swine production. As a collateral effect, these changes have exacerbated the circulation of viruses and challenged our ability to prevent, control, and/or eliminate impactful swine diseases. Recent pandemic events in human and animal health, e.g., SARS-CoV-2 and African swine fever virus, highlight the fact that clinical observations are too slow and inaccurate to form the basis for effective health management decisions: systematic processes that provide timely, reliable data are required. Oral fluid-based surveillance reflects the adaptation of conventional testing methods to an alternative diagnostic specimen. The routine use of oral fluids in commercial farms for PRRSV and PCV2 surveillance was first proposed in 2008 as an efficient and practical improvement on individual pig sampling. Subsequent research expanded on this initial report to include the detection of ≥23 swine viral pathogens and the implementation of oral fluid-based surveillance in large swine populations (> 12,000 pigs). Herein we compile the current information regarding oral fluid collection methods, testing, and surveillance applications in swine production.
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Affiliation(s)
- Alexandra Henao-Diaz
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Veterinary Medical Research Institute, Iowa State University, Ames, Iowa 50011 USA
| | - Luis Giménez-Lirola
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Veterinary Medical Research Institute, Iowa State University, Ames, Iowa 50011 USA
| | - David H Baum
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Veterinary Medical Research Institute, Iowa State University, Ames, Iowa 50011 USA
| | - Jeffrey Zimmerman
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Veterinary Medical Research Institute, Iowa State University, Ames, Iowa 50011 USA
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Detection of Antibodies against Mycobacterium bovis in Oral Fluid from Eurasian Wild Boar. Pathogens 2020; 9:pathogens9040242. [PMID: 32218183 PMCID: PMC7238047 DOI: 10.3390/pathogens9040242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 03/22/2020] [Accepted: 03/23/2020] [Indexed: 11/30/2022] Open
Abstract
The presence of Mycobacterium bovis and other members of the Mycobacterium tuberculosis complex (MTC) is a main concern in wildlife populations such as the Eurasian wild boar (Sus scrofa). Tests detecting antibodies against the MTC are valuable for tuberculosis (TB) monitoring and control and particularly useful in suids. The development of accurate, efficient, and non-invasive new tools to detect exposure to MTC would be highly beneficial for improving disease surveillance. This study aimed to determine if antibodies against MTC could be detected in oral fluid (OF) samples by a new ELISA test (IgG detection) from naturally TB-infected wild boar. For this, individual, paired serum and OF samples were collected from 148 live wild boar in two TB-status areas from Spain and quantitatively used to validate the new ELISA test. Antibodies against MTC were widely detected in OF samples, for which a significant positive correlation (r = 0.83) was found with the validated serology test. OF ELISA sensitivity and specificity were 67.3% and 100%, respectively. The results of this work suggest that OF samples have the potential to be used for MTC diagnosis as a further step in TB surveillance and control in suid populations. Based on our results, further research is warranted and could be performed using non-invasive new tools directly in field conditions to detect exposure to MTC.
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Initial trail results of a magnetic biosensor for the rapid detection of Porcine Reproductive and Respiratory Virus (PRRSV) infection. SENSING AND BIO-SENSING RESEARCH 2020. [DOI: 10.1016/j.sbsr.2019.100315] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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