Measurement of cortisol in dogs infected by Dirofilaria immitis.

Abstract

Cortisol, a steroid produced in the adrenal cortex, is a key hormone used as a measure of stress. Some studies demonstrate that prolonged stress, is associated with reduced survival, fecundity and immunity and that cortisol levels are related to the presence of parasites in some species, with discrepant results. This study aims to investigate the potentially stressful effects of the infection of Dirofilaria immitis in dogs by measuring the levels of serum cortisol before and after the adulticide treatment. The serum of 92 dogs undergoing adulticide therapy was analyzed on days 0, 30, 60 and 90. Furthermore, parasite burden, presence or absence of pulmonary hypertension, and presence or absence of microfilariae, were determined on day 0. The results demonstrated stress in dogs infected by D. immitis, especially in those with presence of pulmonary hypertension. Moreover, at the end of the treatment, when the parasites were eliminated, the levels of cortisol decreased, although remained above reference ranges. These results are similar to other studies which evaluated the effect of several parasites in dogs. More studies are necessary, but results indicated that cortisol could be used as a supporting biomarker in the clinical staging of dogs with heartworm disease.