The impact of outdoor living space access on the dairy cow metabolome profile.

COVID-19, initially understood as a purely respiratory infection, is now defined as a multisystemic disease with comprehensive and long-lasting clinical effects (, ), affecting millions of people worldwide. With the increase in reports of persistent symptoms, the World Health Organization (WHO) defined this condition as Long COVID (LC) and highlighted the need for new clinical approaches to understanding the disease. This condition is defined by manifestations that last at least 2 months, appearing up to 3 months after infection and not explained by other diagnoses (). The pathophysiology of LC remains poorly understood. Proposed mechanisms include viral persistence in tissues, prolonged immune dysregulation, reactivation of latent viruses (EBV, HHV-6), molecular mimicry, autoimmunity, alterations in gut microbiota, and microvascular thrombosis with endothelial dysfunction ().