Procalcitonin meausurements in dogs with dirofilariosis: An indicator of inflammatory response?

Abstract

Dirofilaria immitis infection in dogs elicits a variable inflammatory response that can lead to pulmonary and systemic complications. Identifying reliable biomarkers to assess inflammatory activity may enhance clinical management, particularly in chronic or subclinical cases. This observational cross-sectional study aimed to evaluate the potential utility of procalcitonin (PCT) and C-reactive protein (CRP) as indicators of systemic inflammation in dogs naturally infected with D. immitis. Forty-three dogs from a hyperendemic area were included, comprising 34 infected animals and 9 healthy controls. Serum concentrations of PCT and CRP were measured using validated ELISA and immunochromatographic techniques, respectively. Clinical data, imaging findings, and parasitological parameters such as parasite burden and pulmonary hypertension were also recorded. While CRP levels were significantly higher in infected dogs compared to healthy controls (p = 0.0009), indicating an active inflammatory response, PCT concentrations did not differ significantly between groups (p = 0.3946). Notably, a significant correlation was found between PCT levels and age (p = 0.0167), suggesting a possible influence of ageing or chronic exposure. No associations were observed between biomarker levels and sex, breed, body condition, parasite burden, or the presence of clinical signs. A non-significant trend toward lower PCT and CRP levels in dogs with higher parasite burden may reflect immunotolerance in chronic infections. These findings support the use of CRP as a sensitive inflammatory biomarker in canine dirofilariosis, whereas the diagnostic value of PCT appears limited under non septic conditions. Further studies are necessary to evaluate PCT dynamics throughout disease progression and treatment, and to explore its potential as parts of a multimarker inflammatory panel in veterinary medicine.