Highly variable clinical pictures in dogs naturally infected with Angiostrongylus vasorum

INTRODUCTION. In the past few years, canine angiostrongylosis by Angiostrongylus vasorum has spread in many Countries of Europe. Though awareness of angiostrongylosis is constantly increasing, veterinarians are often faced with the challenging variability of its clinical course (Schnyder et al., 2017 Parasitol. Res. 116: 31-40). In fact, adult parasites, larvae and eggs elicit complex pathogenetic mechanisms which cause unpredictable clinical signs. This case series presents a high variability of clinical pictures showed by naturally infected dogs living in Italy. MATERIALS AND METHODS. Clinical data of 36 dogs with a copromicroscopic diagnosis of angiostrongylosis and referred as individual clinical cases from 4 regions of Central and Southern Italy are here reported. RESULTS AND CONCLUSIONS. Twenty-three (63.9%) dogs showed variable clinical pictures, while 13 (36.1%) were subclinically infected (Figure 1). Cardio-respiratory signs were present in 19 dogs (52.8%) while 14 (38.9%) had non-specific signs (e.g. diarrhea, weight loss, lethargy). Two dogs (5.6%) showed blood disorders (e.g. hematochezia, hemorrhages) and 1 (2.8%) neurological signs (e.g. shivering, hypersalivation). Cough was the predominant sign, showed by 11 dogs (30.5%), followed by dyspnea (8/22.2%), weight loss (6/16.7%), diarrhea (4/11.1%), anorexia (4/11.1%), syncope (3/8.3%) and lethargy (3/8.3%). Other signs were less frequent (Figure 2). There were 17 (47.2%) dogs shedding L1 while exhibiting no cardio-respiratory signs. While 13 (36.1%) had no clinical signs of infection, 4/19 dogs presenting with clinical signs had neither cough nor dyspnea. These data show the extreme unpredictability of angiostrongylosis, which must be included in the differential even when dogs living in endemic areas have non-specific clinical signs. The frequency of subclinical infections renders routine parasitological analysis mandatory for a timely diagnosis and a prompt treatment with efficacious formulations, to minimize the risk of a sudden onset of a potentially fatal disease.