Molecular tracing of dissemination routes of Salmonella spp, Hepatitis E virus and other viruses as fecal indicators in pigs at slaughterhouse Ianiro G.1, Pavoni E2., Alborali G. L.2, Guadagno F.2, Delibato E.1, Treglia I.1, De Sabato. L.1, Monini M.1, Ostanello F.3, Di Bartolo I.1 1 Istituto Superiore di Sanità, Rome, Italy 2 Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna "Bruno Ubertini", Brescia, Italy 3 University di Bologna, Scienze Veterinarie, Bologna, Italy RESULTS & DISCUSSION 4th One Health European Joint Programme Annual Scientific Meeting - 11th-13th April 2022, Orvieto, Italy AIM The aim of this study was to investigate the occurrence of Salmonella spp. and hepatitis E virus (HEV) in pig slaughterhouses, and to identify critical points of the slaughter chain associated with the fecal contamination of carcasses. To this purpose, the detection of animal fecal indicators (porcine adenovirus PAdV, Torque teno sus virus TTSuV and group A rotavirus RVA) was also performed. Swabs were collected from 2 abattoirs in Italy at the end of the slaughtering cycle before cleaning. Environmental (floor, lairage, and trucks), equipment (knives and splitter) and external part of carcasses were sampled. HEV, RVA, TTSuV, PAdV and Salmonella spp. were detected by Real time PCR. Salmonella detection was confirmed by EN ISO 6579- 1:2017. Artificial contamination of samples was performed by using murine norovirus (MNV) to assess the nucleic extraction recovery rate. No samples were positive for HEV. Salmonella spp. was detected in one slaughterhouse, in 2 swabs sampled on the floor under the evisceration station and at lairage (Table 1). The result highlights the presence of Salmonella spp. positive pigs, able to shed the pathogen in feces in both the contaminated areas. In both abattoirs, the presence of PAdV was revealed (7/23 swabs) in several points, including external part of carcasses which was probably cross-contaminated by feces for improper handling (Table 1). Sus TTV was also revealed in both abattoirs (6/23) (Table 1). However, since it can be retrieved in blood and feces, we cannot establish if it is linked to fecal contamination. CONCLUSIONS Results confirmed that Salmonella spp. carriage may occur in pigs at slaughterhouses. HEV is rarer and co-infection with other viruses is frequent. The application of GHP is a main factor for managing carcass contamination at slaughterhouse. METHODS Funding acknowledgement This work was partially supported by funding from the European Union’s Horizon 2020 Research and Innovation programme under grant agreement No 773830: One Health European Joint Programme and from Italian Ministry of Health, grant RF-2016-02361926 (Ricerca Finalizzata anno 2016). Sample Recovery Rate (MNV) HEV TTV PAdV RVA Salm spp. Sampling Site Date ISS1 Not sampled Floor truck after washing ISS2 33.22% 0 0 pos 0 pos Lairage pens (floor) before cleaning 14 July 2021 ISS3 22.38% 0 pos 0 0 0 Scalding water tank caroussel arm 14 July 2021 ISS4 21.92% 0 0 pos 0 0 Surface at 2-knives system tank 14 July 2021 ISS5 100.00% 0 0 0 0 0 Carcass splitter surface 14 July 2021 ISS6 100.00% 0 pos 0 0 0 Evisceration knife 14 July 2021 ISS7 11.19% 0 pos pos 0 pos Evisceration step (floor) 14 July 2021 ISS8 22.22% 0 0 pos 0 0 Outer surface of 3 carcasses after evisceration 14 July 2021 ISS9 100.00% 0 pos 0 0 0 Outer surface of 3 carcasses after evisceration 14 July 2021 ISS10 68.30% 0 0 0 0 0 Outer surface of 3 carcasses after evisceration 14 July 2021 ISS11 95.93% 0 0 0 0 0 Outer surface of 3 carcasses after evisceration 14 July 2021 ISS12 100.00% 0 0 0 0 0 Outer surface of 3 carcasses after evisceration 14 July 2021 BS1 100.00 0 0 pos 0 0 Floor truck after washing October 2021 BS2 37.57 0 0 0 0 0 Lairage pens (floor) before cleaning October 2021 BS3 42.82 0 0 0 0 0 Carcass splitter surface October 2021 BS4 12.44 0 0 pos 0 0 Scalding water tank caroussel arm October 2021 BS5 25.14 0 pos 0 0 0 Evisceration