An investigation of passive antibody and its effects on porcine epidemic diarrhea virus infection

The objectives of this research were to determine the effects of maternally-derived antibodies in protecting piglets against porcine epidemic diarrhea virus (PEDV). In Chapter 3, a passive antibody transfer model was used to evaluate the impact of circulating antibody on the protection of naïve piglets against PEDV. Piglets derived from 6 sows were randomly assigned to receive one of 6 different levels of concentrated serum antibody. In Chapter 4, PEDV-immune and PEDV-negative sows were used to evaluate the impact of lactogenic antibody on the protection of piglets against PEDV. In both studies, piglets were inoculated with PEDV and monitored for 14 days, during which time they remained with their dam. Sow milk, piglet fecal samples, and data on piglet clinical signs, body weight, and body temperature were collected daily. Serum, colostrum, and milk were tested for PEDV antibody by PEDV IgG and IgA ELISAs and by fluorescent focus neutralization (FFN) assay. The analysis showed that both passive antibody and lactogenic antibody contributed to the protection of the neonatal piglets against PEDV infections. Therefore, the optimal protection to piglets will be provided by dams able to deliver sufficient lactogenic immunity, both humoral and cellular, to their offspring. The feasibility of improving oral fluid IgG and/or IgA antibody testing by clarifying samples using chemical treatment was evaluated in Chapter 5. Three chemical formulations based on chitosan and/or Tween-20î were used to treat aliquots of known status oral fluid samples from PEDV-inoculated pigs. All aliquots were tested by PEDV IgG and IgA ELISAs on day post-treatment (DPT) 0, then kept at 4ðC and re-tested on DPT 2, 4, and 6. All formulations went into solution quickly and easily upon addition of oral fluid and the addition of chitosan was shown to effectively clarify oral fluids. Statistical analysis found that neither chitosan nor Tween-20î adversely affected the ELISA results and the treated oral fluid samples were stable over time. Thus, this study found that chitosan could be used to efficiently clarify oral fluid specimens without affecting the results of antibody ELISAs

Detection of \u3ci\u3eMannheimia haemolytica\u3c/i\u3e-Specific IgG, IgM and IgA in Sera and Their Relationship to Respiratory Disease in Cattle

Mannheimia haemolytica is one of the major causes of bovine respiratory disease in cattle. The organism is the primary bacterium isolated from calves and young cattle affected with enzootic pneumonia. Novel indirect ELISAs were developed and evaluated to enable quantification of antibody responses to whole cell antigens using M. haemolytica A1 strain P1148. In this study, the ELISAs were initially developed using sera from both M. haemolytica-culture-free and clinically infected cattle, then the final prototypes were tested in the validation phase using a larger set of known-status M. haemolytica sera (n = 145) collected from feedlot cattle. The test showed good inter-assay and intra-assay repeatability. Diagnostic sensitivity and specificity were estimated at 91% and 87% for IgG at a cutoff of S/P ≥ 0.8. IgM diagnostic sensitivity and specificity were 91% and 81% at a cutoff of sample to positive (S/P) ratio ≥ 0.8. IgA diagnostic sensitivity was 89% whereas specificity was 78% at a cutoff of S/P ≥ 0.2. ELISA results of all isotypes were related to the diagnosis of respiratory disease and isolation of M. haemolytica (p-value \u3c 0.05). These data suggest that M. haemolytica ELISAs can be adapted to the detection and quantification of antibody in serum specimens and support the use of these tests for the disease surveillance and disease prevention research in feedlot cattle

Detection of pseudorabies virus antibody in swine oral fluid using a serum whole-virus indirect ELISA

We evaluated the detection of pseudorabies virus (PRV) antibodies in swine oral fluid. Oral fluid and serum samples were obtained from 40 pigs allocated to 4 treatment groups (10 pigs/group): negative control (NC); wild-type PRV inoculation (PRV 3CR Ossabaw; hereafter PRV); PRV vaccination (Ingelvac Aujeszky MLV; Boehringer Ingelheim; hereafter MLV); and PRV vaccination followed by PRV inoculation at 21 d post-vaccination (MLV-PRV). Using a serum PRV whole-virus indirect IgG ELISA (Idexx Laboratories) adapted to the oral fluid matrix, PRV antibody was detected in oral fluid samples from treatment groups PRV, MLV, and MLV-PRV in a pattern similar to serum. Vaccination alone produced a low oral fluid antibody response (groups MLV and MLV-PRV), but a strong anamnestic response was observed following challenge with wild-type virus (group PRV). Analyses of the oral fluid PRV indirect IgG ELISA results showed good binary diagnostic performance (area under ROC curve = 93%) and excellent assay repeatability (intra-class correlation coefficient = 99.3%). The demonstrable presence of PRV antibodies in swine oral fluids suggests the possible use of oral fluids in pseudorabies surveillance

Does Circulating Antibody Play a Role in the Protection of Piglets against Porcine Epidemic Diarrhea Virus?

The contribution of circulating antibody to the protection of naïve piglets against porcine epidemic diarrhea virus (PEDV) was evaluated using a passive antibody transfer model. Piglets (n = 62) derived from 6 sows were assigned to one of 6 different treatments using a randomized block design which provided for allocation of all treatments to all sows\u27 litters. Each treatment was designed to achieve a different level of circulating anti-PEDV antibody via intraperitoneally administration of concentrated serum antibody. Piglets were orally inoculated with PEDV (USA/IN/2013/19338E, 1 x 103 TCID50 per piglet) 24 hours later and then monitored for 14 days. Piglets remained with their dam throughout the experiment. Sow milk samples, piglet fecal samples, and data on piglet clinical signs, body weight, and body temperature were collected daily. Fecal samples were tested by PEDV real-time reverse transcriptase PCR. Serum, colostrum, and milk were tested for PEDV IgG, IgA, and virus-neutralizing antibody. The data were evaluated for the effects of systemic PEDV antibody levels on growth, body temperature, fecal shedding, survival, and antibody response. The analysis showed that circulating antibody partially ameliorated the effect of PEDV infection. Specifically, antibody-positive groups returned to normal body temperature faster and demonstrated a higher rate of survivability than piglets without PEDV antibody. When combined with previous literature on PEDV, it can be concluded that both systemic antibodies and maternal secretory IgA in milk contribute to the protection of the neonatal pig against PEDV infections. Overall, the results of this experiment suggested that passively administered circulating antibodies contributed to the protection of neonatal piglets against PEDV infection

An investigation of passive antibody and its effects on porcine epidemic diarrhea virus infection

The objectives of this research were to determine the effects of maternally-derived antibodies in protecting piglets against porcine epidemic diarrhea virus (PEDV). In Chapter 3, a passive antibody transfer model was used to evaluate the impact of circulating antibody on the protection of naà ¯ve piglets against PEDV. Piglets derived from 6 sows were randomly assigned to receive one of 6 different levels of concentrated serum antibody. In Chapter 4, PEDV-immune and PEDV-negative sows were used to evaluate the impact of lactogenic antibody on the protection of piglets against PEDV. In both studies, piglets were inoculated with PEDV and monitored for 14 days, during which time they remained with their dam. Sow milk, piglet fecal samples, and data on piglet clinical signs, body weight, and body temperature were collected daily. Serum, colostrum, and milk were tested for PEDV antibody by PEDV IgG and IgA ELISAs and by fluorescent focus neutralization (FFN) assay. The analysis showed that both passive antibody and lactogenic antibody contributed to the protection of the neonatal piglets against PEDV infections. Therefore, the optimal protection to piglets will be provided by dams able to deliver sufficient lactogenic immunity, both humoral and cellular, to their offspring. The feasibility of improving oral fluid IgG and/or IgA antibody testing by clarifying samples using chemical treatment was evaluated in Chapter 5. Three chemical formulations based on chitosan and/or Tween-20à ® were used to treat aliquots of known status oral fluid samples from PEDV-inoculated pigs. All aliquots were tested by PEDV IgG and IgA ELISAs on day post-treatment (DPT) 0, then kept at 4à °C and re-tested on DPT 2, 4, and 6. All formulations went into solution quickly and easily upon addition of oral fluid and the addition of chitosan was shown to effectively clarify oral fluids. Statistical analysis found that neither chitosan nor Tween-20à ® adversely affected the ELISA results and the treated oral fluid samples were stable over time. Thus, this study found that chitosan could be used to efficiently clarify oral fluid specimens without affecting the results of antibody ELISAs.</p

A review of foot-and-mouth disease virus (FMDV) testing in livestock with an emphasis on the use of alternative diagnostic specimens

Foot-and-mouth disease virus (FMDV) remains an important pathogen of livestock more than 120 years after it was identified, with annual costs from production losses and vaccination estimated at €5.3–€17 billion (US$6.5–US$21 billion) in FMDV-endemic areas. Control and eradication are difficult because FMDV is highly contagious, genetically and antigenically diverse, infectious for a wide variety of species, able to establish subclinical carriers in ruminants, and widely geographically distributed. For early detection, sustained control, or eradication, sensitive and specific FMDV surveillance procedures compatible with high through-put testing platforms are required. At present, surveillance relies on the detection of FMDV-specific antibody or virus, most commonly in individual animal serum, vesicular fluid, or epithelial specimens. However, FMDV or antibody are also detectable in other body secretions and specimens, e.g., buccal and nasal secretions, respiratory exhalations (aerosols), mammary secretions, urine, feces, and environmental samples. These alternative specimens offer non-invasive diagnostic alternatives to individual animal sampling and the potential for more efficient, responsive, and cost-effective surveillance. Herein we review FMDV testing methods for contemporary and alternative diagnostic specimens and their application to FMDV surveillance in livestock (cattle, swine, sheep, and goats).This is a manuscript of an article published as Poonsuk, Korakrit, Luis Giménez-Lirola, and Jeffrey J. Zimmerman. "A review of foot-and-mouth disease virus (FMDV) testing in livestock with an emphasis on the use of alternative diagnostic specimens." Animal Health Research Reviews 19, no. 2 (2018): 100-112. doi: https://doi.org/10.1017/S1466252318000063. Posted with Permission. Copyright © Cambridge University Press 2018. CC BY-NC-N

Detection of porcine epidemic diarrhea virus (PEDV) IgG and IgA in muscle tissue exudate (“meat juice”) specimens

Abstract The diagnostic performance of porcine epidemic diarrhea virus (PEDV) IgG and IgA ELISAs was evaluated using paired serum and meat juice samples collected from PEDV-negative (n = 50) and PEDV-inoculated pigs (n = 87). Serum samples were tested by PEDV (IgG, IgA) ELISAs using a procedure performed routinely at the Iowa State University-Veterinary Diagnostic Laboratory (ISU-VDL). Serum samples were tested using PEDV serum IgG and IgA ELISA procedures as routinely performed at the Iowa State University-Veterinary Diagnostic Laboratory (ISU-VDL). Serum samples were diluted 1:50 and conjugate concentrations were 1/20,000 for IgG and 1/3000 for IgA. Meat juice samples were tested using the serum PEDV IgG and IgA ELISAs, with modifications, i.e., meat juice samples were diluted 1:25 and conjugate concentrations were 1/40,000 for IgG and 1/10,000 for IgA. Receiver operator characteristic (ROC) curve analyses were used to estimate diagnostic sensitivities and specificities over a range of sample-to-positive (S/P) cutoffs. Consistent with previous reports, this study showed that the PEDV IgG and IgA meat juice ELISAs provided excellent diagnostic performance and suggest that meat juice recovered from samples collected at slaughter could be used in routine PEDV surveillance

Detection of porcine epidemic diarrhea virus (PEDV) IgG and IgA in muscle tissue exudate (“meat juice”) specimens

The diagnostic performance of porcine epidemic diarrhea virus (PEDV) IgG and IgA ELISAs was evaluated using paired serum and meat juice samples collected from PEDV-negative (n = 50) and PEDV-inoculated pigs (n = 87). Serum samples were tested by PEDV (IgG, IgA) ELISAs using a procedure performed routinely at the Iowa State University-Veterinary Diagnostic Laboratory (ISU-VDL). Serum samples were tested using PEDV serum IgG and IgA ELISA procedures as routinely performed at the Iowa State University-Veterinary Diagnostic Laboratory (ISU-VDL). Serum samples were diluted 1:50 and conjugate concentrations were 1/20,000 for IgG and 1/3000 for IgA. Meat juice samples were tested using the serum PEDV IgG and IgA ELISAs, with modifications, i.e., meat juice samples were diluted 1:25 and conjugate concentrations were 1/40,000 for IgG and 1/10,000 for IgA. Receiver operator characteristic (ROC) curve analyses were used to estimate diagnostic sensitivities and specificities over a range of sample-to-positive (S/P) cutoffs. Consistent with previous reports, this study showed that the PEDV IgG and IgA meat juice ELISAs provided excellent diagnostic performance and suggest that meat juice recovered from samples collected at slaughter could be used in routine PEDV surveillance.This article is published as Poonsuk, Korakrit, Ting-Yu Cheng, Ju Ji, Jeffrey Zimmerman, and Luis Giménez-Lirola. "Detection of porcine epidemic diarrhea virus (PEDV) IgG and IgA in muscle tissue exudate (“meat juice”) specimens." Porcine Health Management 4, no. 1 (2018): 1-5. DOI: 10.1186/s40813-018-0107-4. Copyright 2018 The Author(s). Attribution 4.0 International (CC BY 4.0). Posted with permission

Detection of Actinobacillus pleuropneumoniae ApxIV toxin antibody in serum and oral fluid specimens from pigs inoculated under experimental conditions

Introduction: The prevention and control of Actinobacillus pleuropneumoniae in commercial production settings is based on serological monitoring. Enzyme-linked immunosorbent assays (ELISAs) have been developed to detect specific antibodies against a variety of A. pleuropneumoniae antigens, including long-chain lipopolysaccharides (LPS) and the ApxIV toxin, a repeats-in-toxin (RTX) exotoxin unique to A. pleuropneumoniae and produced by all serovars. The objective of this study was to describe ApxIV antibody responses in serum and oral fluid of pigs. Material and Methods: Four groups of pigs (six pigs per group) were inoculated with A. pleuropneumoniae serovars 1, 5, 7, or 12. Weekly serum samples and daily oral fluid samples were collected from individual pigs for 56 days post inoculation (DPI) and tested by LPS and ApxIV ELISAs. The ApxIV ELISA was run in three formats to detect immunlgobulins M, G, and A (IgM, IgG and IgA) while the LPS ELISA detected only IgG. Results: All pigs inoculated with A. pleuropneumoniae serovars 1 and 7 were LPS ELISA serum antibody positive from DPI 14 to 56. A transient and weak LPS ELISA antibody response was observed in pigs inoculated with serovar 5 and a single antibody positive pig was observed in serovar 12 at ≥35 DPI. Notably, ApxIV serum and oral fluid antibody responses in pig inoculated with serovars 1 and 7 reflected the patterns observed for LPS antibody, albeit with a 14 to 21 day delay. Conclusion: This work suggests that ELISAs based on ApxIV antibody detection in oral fluid samples could be effective in population monitoring for A. pleuropneumoniae.This article is published as González, Wendy, Luis G. Giménez-Lirola, Ashley Holmes, Sergio Lizano, Christa Goodell, Korakrit Poonsuk, Panchan Sitthicharoenchai, Yaxuan Sun, and Jeffrey Zimmerman. "Detection of Actinobacillus pleuropneumoniae ApxIV toxin antibody in serum and oral fluid specimens from pigs inoculated under experimental conditions." Journal of Veterinary Research 61, no. 2 (2017): 163. DOI: 10.1515/jvetres-2017-0021. Copyright 2017 W. González et al. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0). Posted with permission

Detection of Actinobacillus pleuropneumoniae ApxIV toxin antibody in serum and oral fluid specimens from pigs inoculated under experimental conditions

Introduction: The prevention and control of Actinobacillus pleuropneumoniae in commercial production settings is based on serological monitoring. Enzyme-linked immunosorbent assays (ELISAs) have been developed to detect specific antibodies against a variety of A. pleuropneumoniae antigens, including long-chain lipopolysaccharides (LPS) and the ApxIV toxin, a repeats-in-toxin (RTX) exotoxin unique to A. pleuropneumoniae and produced by all serovars. The objective of this study was to describe ApxIV antibody responses in serum and oral fluid of pigs