Use of oral fluids for efficient monitoring of influenza viruses in swine herds in Colombia

34 Background: Influenza A virus (IAV) surveillance in swine is critical due to the direct impact of 35 the disease in pork industry but also because IAV are prone to interspecies transmission (from 36 human to pigs and vice versa), and therefore its monitoring is critical from public and animal health 37 perspectives. Currently there are several diagnostic techniques available to detect IAV infection 38 Received: May 17, 2021; Accepted: October 5, 2021 Corresponding author: Karl Ciuoderis. Laboratorio Genómico One Health, Universidad Nacional de Colombia, bloque M15, Medellín, Colombia. E-mail: coord_cwohc@unal.edu.co This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. eISSN: 2256-2958 Rev Colomb Cienc Pecu from nasal samples in swine, however, other samples such as oral fluids (OF) have been 39 implemented as novel alternatives for pathogen detection. The OF allow an efficient and feasible 40 detection of diseases at lower cost at a herd level, with lower risk of stress for animals. Objective: 41 Describe a surveillance strategy of IAV at herd level during respiratory disease outbreaks in swine 42 farms in tropical settings using porcine oral fluids. Methods: Active surveillance strategy was 43 conducted in five selected swine farms with past records of respiratory disease. Swine OF were 44 collected for IAV testing. An OF sample was described as a pen-based specimen collected from a 45 group of >20 pigs per pen and/or per barn (if they were stall-housed individually but having close 46 contact between them). IAV infection was investigated in OF by rRT-PCR testing, and confirmed 47 by viral isolation in cell culture. Results: IAV detection was conducted in five purposively selected 48 farms between 2014-2017. We investigated a total of 18 respiratory disease outbreak events. From 49 the total 1444 OF samples tested, we found 107 (7.4%) positives to IAV by rRT-PCR. 50 Additionally, 9 IAV isolates were obtained, and all were further identified as H1 subtype. 51 Conclusions: Results of our study demonstrated how OF can be easily implemented as a novel, 52 user-friendly, welfare-friendly, accurate and cost-effective sampling method for active 53 surveillance and monitoring of IAV infections in swine farms in tropical settings. 54