Influenza viruses are highly variable pathogens that infect a wide range of mammalian and avian species. According to the internal conserved proteins (nucleoprotein: NP, and matrix proteins: M), these viruses are classified into type A, B, C, and D. Influenza A virus in swine is of significant importance to the industry since it is responsible of endemic infections that lead to high economic loses derived from poor weight gain, reproductive disorders, and the role it plays in Porcine Respiratory Disease Complex (PRDC). To the date, swine influenza virus (SIV) diagnosis keeps on being based in complex and expensive technologies such as RT-qPCR. In this study, we aimed to improved actual tools by the implementation of new bioreceptors molecules; aptamers. First, three different aptamers have been selected using the recombinant NP of Influenza A virus expressed in insect cells, as target. Then, these molecules have been used for the development of an Enzyme-Linked AptaSorbent Assay (ELASA) in combination with specific monoclonal antibodies for Influenza A detection. A total of 171 field samples (nasal swabs) have been evaluated with the newly developed assay obtaining a 79.7 % and 98.1 % sensitivity and specificity respectively, using real time RT-PCR as standard assay. These results suggest that the assay is a promising method that could be used for Influenza A detection in analysis laboratories facilitating surveillance labours.

Livestock industry supports the livelihood of around 1.3 billion people in the world, with swine industry contributing with 30 % of total livestock production worldwide. To maintain and guarantee this production, a pivotal point according to the OIE is addressing potential biohazards. To control them, permanent sero-surveillance is crucial to achieve more focused veterinary public health intervention and prevention strategies, to break the chains of transmission, and to enable fast responses against outbreaks. Within this context, multiplex assays are powerful tools with the potential to simplify surveillance programs, since they reduce time, labour, and variability within analysis. In the present work, we developed a multiplex bead-based assay for the detection of specific antibodies to six relevant pathogens affecting swine: ASFV, CSFV, PRRSV, SIV, TB, and HEV. The most immunogenic target antigen of each pathogen was selected as the target protein to coat different microsphere regions in order to develop this multiplex assay. A total of 1544 serum samples from experimental infections as well as field samples were included in the analysis. The 6plex assay exhibited credible diagnostic parameters with sensitivities ranging from 87.0 % to 97.5 % and specificities ranging from 87.9 % to 100.0 %, demonstrating it to be a potential high throughput tool for surveillance of infectious diseases in swine.