Field efficacy of Advocate® (Bayer Animal Health) in the treatment of dogs naturally infected with Angiostrongylus vasorum

INTRODUCTION. Angiostrongylus vasorum lives in the pulmonary arteries and heart of dogs and other animals, that become infected ingesting L3s in gastropod intermediate hosts. Dog angiostrongylosis can be subclinical for a long time, but most often it causes varying clinical pictures that, if untreated, are life-threatening. Despite the clinical importance of the disease and the current geographic expansion of A. vasorum, few therapeutics are licensed to treat the infection. Advocate® (Bayer Animal Health) spot on has been marketed a decade ago to treat dog angiostrongylosis in single or repeated administrations. This study aimed at monitoring the efficacy of Advocate® in treating dog angiostrongylosis in clinical settings from different geographical regions of Italy. MATERIALS AND METHODS. A total of 75 naturally infected dogs, namely 15 from Abruzzo (Site A), Lazio (Site B), Molise (Site C), and 60 from Campania (Site D) regions, were included. After a clinical examination, each dog received (day 0) a single dose of Advocate®. All dogs were clinically examined and subjected to the Baermann’s test at intervals of 28 days and, when still positive, they received another Advocate® administration until negativization at the Baermann’s test and at the clinical observations. RESULTS AND CONCLUSIONS. All dogs from sites A-C tested Baermann-negative after one dose of Advocate® (efficacy on site 100%). Fifty animals from site D received two administrations, at day 0 and +28 (efficacy on site 83%), while a third dose at day +56 was necessary for the remaining 10 dogs (efficacy on site 100%). All dogs showed a complete clinical recovery in concomitance with the Baermann’s negativization. Overall, the efficacy of one, two or three Advocate® topical doses was 20%, 87% and 100%. This study confirmed the efficacy of Advocate® in treating dog angiostrongylosis. As previously shown (Di Cesare et al., 2014, Prax. Vet, 35: 22-26; Traversa et al., 2013, Parasitol. Res, 112: 2473-2480; Willesen et al., 2007, Parasitol. Res, 147: 258-264), some cases require repeated administrations to cure the infection, especially, as for dogs from Site D, in the case of intense local parasitological pressure that may lead to severe infections with high parasite burden.