Cytokine dysregulation and lymphopenia in dogs naturally infected with canine parvovirus type 2c.

Canine parvovirus type 2 (CPV-2) infection remains a major cause of morbidity and mortality in dogs, particularly in unvaccinated puppies. Despite its clinical significance, the immunological mechanisms driving disease progression remain poorly understood. In this study, we analysed hematologic parameters, molecular viral typing, and the plasma cytokine profiles of 41 dogs naturally infected with CPV-2c, compared to 15 healthy controls. Lymphopenia and elevated IL-6, MCP-1, IL-8, IL-10, and KC-like levels were strongly associated with mortality. Conversely, lower IFN-γ levels correlated with recovery. Dead dogs exhibited strong correlations between IL-6 and KC-like, IL-6 and MCP-1, and IL-8 and MCP-1. All infected dogs harboured the CPV-2c variant, as confirmed by RFLP and sequencing. Although these results are based on single time-point measurements at admission, they highlight that cytokine profiling, particularly of IL-6, MCP-1 and IFN-γ, alongside lymphocyte counts, may serve as useful biomarkers for disease severity and prognosis in CPV-2c-infected dogs.