Presence of toxin-producing bacterial pathogens and associated risk factors in neonatal diarrhea of piglets on commercial sow farms in Vietnam

Background and Aim: Neonatal piglet diarrhea (NPD) remains a significant challenge in the swine industry, contributing to elevated pre-weaning mortality, reduced productivity, and increased economic losses. In Vietnam, despite the growing importance of commercial pig production, comprehensive studies investigating the epidemiology of NPD and associated bacterial pathogens are lacking. This study aimed to assess the prevalence of Escherichia coli, Clostridium perfringens, and Clostridioides difficile and to identify risk factors contributing to NPD on Vietnamese sow farms. Materials and Methods: A cross-sectional study was conducted on 40 commercial sow farms across North, Central, and South Vietnam between August and December 2023. Structured questionnaires captured data on farm characteristics, management practices, and health interventions. Fecal samples from symptomatic piglets aged 1–14 days were pooled and analyzed using multiplex quantitative polymerase chain reaction to detect virulence genes of E. coli (F4, F5, F6, LT), C. perfringens (alpha, beta, and epsilon toxins), and C. difficile (toxins A and B). Logistic and ordinal regression models were applied to assess associations between risk factors and pathogen prevalence. Results: All farms tested positive for at least one pathogen. C. perfringens was the most prevalent (97.37%), followed by E. coli (46.49%) and C. difficile (39.47%). Co-infections involving multiple pathogens were common (64.91%), with C. perfringens consistently present in all mixed infections. Key virulence genes detected included LT (35.96%), alpha toxin (95.61%), and toxin A (20.17%). Significant risk factors included farm type, region, weaning performance, and peripartum antibiotic administration route. Notably, farms using mixed-feed antibiotics exhibited higher E. coli prevalence. Larger farms and those practicing early piglet relocation also showed increased pathogen diversity. Conclusion: This study presents the first national-scale assessment of bacterial pathogens in NPD across Vietnamese sow farms. The findings highlight the high burden of toxin-producing bacteria, frequent co-infections, and multiple farm-level risk factors. Interventions such as targeted vaccination, optimized antibiotic use, improved weaning practices, and enhanced regional surveillance are essential for mitigating NPD impacts and improving piglet health outcomes in Vietnam.