Osteomyelitis related lameness across animal species: pathophysiology, etiology, epidemiology and experimental model approaches.

Osteomyelitis is an inflammatory disorder resulting from the invasion of opportunistic pathogens into bones and bone marrows, causing necrosis and affecting multiple animal groups. It represents one of the most prevalent musculoskeletal diseases, imposing substantial economic losses and raising significant animal welfare concerns across livestock and poultry industries. The pathophysiology of osteomyelitis is characterized by mechanisms of disease development, clinical age, the specific anatomic site in the bone, and structural differences between adults and juveniles. The inability of animals to communicate their discomfort restricts the early diagnosis and treatment of osteomyelitis lameness. Furthermore, osteomyelitis-related lameness is complicated by multiple independent factors, including monomicrobial and polymicrobial infections, latent infections from immune suppression, and emergence of antimicrobial resistance. Chronic osteomyelitis necessitates surgical debridement or additional drug delivery systems in treatment regimen, in addition to antimicrobial drugs. This study proposes a novel framework describing osteomyelitis related lameness linking species-specific patterns with shared pathogenesis. Additionally, this review discusses the pathophysiology, clinical manifestation, epidemiology, and etiology of osteomyelitis related lameness in multiple animal species, particularly livestock and poultry. Furthermore, the development of new antimicrobial compounds and drug delivery to combat osteomyelitis requires an appropriate animal model mimicking the nature of the disease. Thus, this review also presents the pros and cons of existing animal models in osteomyelitis research, including animal welfare concerns of the experimental osteomyelitis models to tackle polymicrobial osteomyelitis.