Detection of Anti-Influenza A Nucleoprotein Antibodies in Pigs Using a Commercial Influenza Epitope-Blocking Enzyme-Linked Immunosorbent Assay Developed for Avian Species

Abstract

Influenza virus causes acute respiratory disease in pigs and is of concern for its potential public health significance. Many subtypes of influenza virus have been isolated from pigs, and the virus continues to evolve in swine populations. Current antibody assays have limited antigenic recognition, and accurate, broad-spectrum, high through-put screening tests are needed to detect infections in swine herds and to aid in the implementation of control measures. In the current study, a commercial blocking enzyme-linked immunosorbent assay (ELISA) developed for the detection of Influenza A virus nucleoprotein antibodies in avian species was evaluated for the detection of anti-influenza serum antibodies in swine. Serum samples used to evaluate the test were archived samples from influenza research conducted at the U.S. Department of Agriculture-Agricultural Research Service-National Animal Disease Center and included samples from influenza-inoculated pigs (H1N1, H1N2, H2N3, and H3N2), contact-infected pigs, vaccinated pigs, and negative controls. Based on samples of known status (n = 453), a receiver operating characteristic (ROC) curve analysis of the ELISA results estimated the optimized diagnostic sensitivity and specificity at 96.6% (95% confidence interval [CI]: 92.3, 98.9) and 99.3% (95% CI: 97.6, 99.9), respectively. By using the cutoff established in the ROC analysis, the assay was evaluated in pigs infected with 2 isolates of the 2009 pandemic H1N1 virus. Overall, the assay showed excellent diagnostic performance against the range of influenza subtypes investigated and could serve as a useful screening assay for swine.

Genome plasticity of triple-reassortant H1N1 influenza A virus during infection of vaccinated pigs

“…Eleven 3-week-old specific-pathogen-free piglets were selected from a serologically IAV-negative swine herd and moved to the University of Minnesota animal research units. The IAV-negative status was confirmed by testing individual nasal swabs with RRT-PCR targeting the M gene (Slomka et al, 2010;Spackman & Suarez, 2008) and serum samples by ELISA (Influenza Ab Test kit; IDEXX Laboratories) for antibodies against NP (Ciacci-Zanella et al, 2010). Viral RNA was eluted using 50 ml of each sample into 50 ml elution buffer using an Ambion MagMax virus RNA isolation kit (Life Technologies).…”

Pathogenicity and Transmission in Pigs of the Novel A(H3N2)v Influenza Virus Isolated from Humans and Characterization of Swine H3N2 Viruses Isolated in 2010-2011

“…A total of 56 3-weekold conventional pigs were obtained from a healthy herd free of SIV, porcine reproductive and respiratory syndrome virus (PRRSV), and Mycoplasma hyopneumoniae. Upon arrival, pigs were confirmed seronegative to SIV by Flock Check AI MultiS-Screen diagnostic kit (Idexx Laboratories, ME) as described previously (7). All pigs were treated with ceftiofur crystalline free acid (Pfizer, NY) and enrofloxacin (Bayer HealthCare AG, NJ) to reduce bacterial contaminants prior to the start of the study.…”

A multi-virus detectable microfluidic electrochemical immunosensor for simultaneous detection of H1N1, H5N1, and H7N9 virus using ZnO nanorods for sensitivity enhancement

“…The promising and conventional assays such as ELISA (enzyme-linked immunosorbent assay) [7], real-time polymerase chain reaction (RT-PCR), or western blots have been generally performed to monitor the influenza A virus [8][9][10]. However, the traditional methods face limitations that usually require long-time processing, trained personnel, or wellequipped laboratory where several expensive equipments are placed.…”