Neutrophil myeloperoxidase index in juvenile dogs with parvoviral enteritis

Canine parvovirus is one of the most common causes of infectious enteritis in puppies worldwide. Although various biomarkers have been evaluated to predict prognosis in dogs with parvoviral enteritis (CPE), many are not feasible in routine practice. The neutrophil myeloperoxidase index (MPXI; derived from the Advia 2120 hematology analyzer, Siemens), has shown promise as a marker of inflammation and disease severity in other species. We compared the MPXI in 47 client-owned dogs with established prognostic indicators, including total WBC, neutrophil and lymphocyte count, and serum concentrations of total thyroxine, cortisol, and C-reactive protein (CRP). The MPXI in dogs with CPE did not differ significantly from healthy controls when measured at admission ( p = 0.444), at 24 h ( p = 0.332), or at 48 h ( p = 0.279) after admission. At 24 h after admission, MPXI had a strong positive correlation with serum cortisol ( r = 0.87; p < 0.001) and CRP ( r = 0.71; p = 0.003) concentrations and a strong negative correlation with WBC ( r = −0.82; p < 0.001), neutrophil ( r = −0.77; p < 0.001), and lymphocyte ( r = −0.90; p < 0.001) counts, as well as serum thyroxine concentration ( r = −0.78; p < 0.001). MPXI did not distinguish between diseased and healthy animals. However, increased MPXI in dogs with parvoviral enteritis may indicate the presence of immunoparalysis and be associated with a worse prognosis. Larger prospective studies, including mortality data, are warranted to evaluate MPXI as an accessible and cost-effective prognostic biomarker in CPE.