The Treatment of Contagious Ecthyma in Lambs with a Local Anaesthetic/Antiseptic Wound Formulation Lowers Serum Amyloid A Responses

Contagious ecthyma (CE) is a widespread, highly contagious zoonotic skin disease of small ruminants caused by the Orf virus (ORFV), leading to substantial economic losses and welfare concerns. There is no specific treatment, with topical antiseptics and oral or parenteral antibiotics often administered for preventing secondary infections, risking antimicrobial resistance. This study assessed the effect of treating CE in lambs with an antibiotic-free topical anaesthetic/antiseptic formulation (Tri-Solfen^®; T-S; Medical Ethics, Australia/MultiSolfen^®; M-S; Dechra, UK). Serum amyloid A (SAA), a marker of systemic inflammation, was measured in both experimentally and naturally infected lambs allocated to treated and untreated groups. Samples were collected prior to (T0) and at 2 (T2), 7 (T7) and 14 (T14) days post-treatment in experimentally infected lambs and at T0, 10 (T10) and 20 (T20) days post-treatment in naturally affected lambs. In the experimental infection, SAA concentrations were lower in the treated group than in controls at T7 and significantly lower at T14. In the natural outbreak, SAA concentrations significantly decreased over time in the treated group, with a consistent trend toward lower values than in controls. These findings indicate that this therapeutic formulation reduces systemic inflammatory responses in lambs affected by CE, supporting its use as an alternative to antibiotics.