Clinical, hematological, biochemical, and biomarker alterations in neonatal canine sepsis

Sepsis is one of the leading causes of mortality during the first weeks of life in canine neonates, and early diagnosis is essential to reduce these rates. This study aimed to evaluate changes in clinical, hematological, biochemical, and biomarker parameters (procalcitonin, C-reactive protein, and troponin I levels) in neonatal sepsis in dogs. Descriptive statistics, normality testing, group comparisons, and Pearson or Spearman correlations were performed, with significance set at p < 0.05. Biomarker cut-off values were determined using ROC curve analysis based on sensitivity and specificity above 80%. Thirty-one neonates were included, with 17 animals in the sepsis group (SG) and 14 in the control group (CG). In the assessment of clinical parameters, signs of systemic infection, such as diarrhea, erythema of the body, omphalitis, ecchymoses or hematomas, and cyanosis or necrosis of the extremities, were observed. Neonates in the SG showed bradycardia (p<0.05), hypothermia (p<0.05), and reduced neurological reflexes (p<0.05). Leukopenia (p<0.05), hyperlactatemia (p<0.01), hyperkalemia (p<0.05), and increased cardiac troponin I (p<0.01) were observed in the SG. A negative correlation was detected between the leukocyte count and the lactate concentration (r = -0.59; p<0.01) and between the neutrophil count and the troponin I concentration (r = -0.57; p<0.01). A positive correlation was observed between body temperature and leukocytes (r = 0.54, p < 0.01). Additionally, there was a trend toward thrombocytopenia, hypoglycemia, and increased CRP in the SG, although these findings did not reach statistical significance. The origin of the infections was predominantly maternal (intrauterine or via mastitis), with isolation of beta-hemolytic Streptococcus from uterine swabs (41.2%), Staphylococcus sp. from uterine swabs and milk (35.3%), and Streptococcus sp. from milk only (23.5%). Future serial studies are needed to characterize biomarker kinetics during infection. Early diagnosis of neonatal canine sepsis relies on litter monitoring, clinical signs and laboratory tests, including leukopenia, bacterial culture, lactate (≥3mmol/L), and cardiac troponin I (≥0.1ng/dL).