A case report of exudative epidermitis in a large-scale multiparous pig farm in China under the background of African swine fever prevention

Background Since the outbreak of African swine fever in China in 2018, many pig farms in China have implemented very strict biosecurity measures to prevent and control African swine fever. Against this backdrop, the adaptation, isolation and acclimatization of newly commissioned sows have all been simplified accordingly. Case presentation The sow farm is located in the northern part of Shandong Province,China, and uses negative-pressure air filtration. It has a total of six production lines, each with a basic sow population of 3,300. After commissioning in December 2023, an outbreak of exudative epidermitis occurred in April 2024, affecting five production lines (A, B, C, D, and E)with a maximum incidence rate of 76.67%.Through quantitative PCR, bacterial culture, histopathological examination, and metagenomic sequencing, the primary pathogens were identified as Staphylococcus suis and Staphylococcus aureus . The clinical manifestations included skin ulcers in piglets, greasy crusts all over the body, and irregular ulcers on the head and neck, hooves, and abdomen of sows. The etiological analysis suggested that the outbreak might be related to the acclimatization of introduced breeds, production management, deworming, and porcine circovirus. Conclusions This case report documents an outbreak of exudative epidermitis caused by a mixed infection of Staphylococcus suis and Staphylococcus aureus, resulting in substantial losses. It highlights the importance of controlling bacterial diseases, in addition to viral diseases, under the backdrop of African swine fever prevention and control. Once an outbreak of exudative epidermitis occurs, measures such as sow cleaning and deworming, reducing environmental bacterial load, enhancing piglet resistance, minimizing piglet wounds, treating sows, and treating piglets can be implemented to control the epidemic.