Atypical intraocular migration of Angiostronglus vasorum

INTRODUCTION. Angiostrongylus vasorum is a nematode which usually inhabitsthe pulmonary arteries and right ventricle of wild and domestic canids (Morgan et al., 2005 Trends Parasitol. 21: 49-51). Clinical manifestations vary from insidious and non-specific signs (mostly respiratory and neurological manifestations) to fatal cardiopulmonary insufficiency (Ferdushy et al., 2010 Parasitol Res. 107: 765-71). In extremely rare cases, larvae can migrate through the host’s body and reach atypical tissues such as the anterior chamber of the eye, but the mechanism of migration is still unclear (Colella et al., 2016 Parasit Vectors. 9: 161). This report describes the case of two intraocular A. vasorum specimens in an 18-months old dog living in the countryside of Terni, Central Italy. MATERIALS AND METHODS. The patient was referred for an ophthalmological examination due to the presence of two motile parasites in the anterior chamber of one eye. The medical historyshowed that hehad several episodes of recurrent cough in the past. Physical and imaging (thoracic X-ray and ultrasound) examinations were carried out, along with a complete hematobiochemical analysis and modified Knott test. The intraocular parasites were surgically removed and preserved in 70% ethanol for morphological and biomolecular identification. Serum and aqueous humor were tested forantigens of Dirofilaria immitis (SNAP 4DX Plus, IDEXX, Westbrook, US) and A. vasorum (AngioDetect, IDEXX, Westbrook, US). A stool sample has been examined using the Baermann’s method. RESULTS AND CONCLUSIONS. The intraocular parasites where morphologically consistent with metastrongylid and identified by PCR as A. vasorum. Both serum and aqueous humor yielded positive for AngioDetect test, and larvae of A. vasorum were retrieved at the Baermann’stest. All tests for D. immitis were negative. Thoracic X-ray and ultrasound showed findings compatible with angiostrongylosis, i.e. areas of subpleural lung consolidation. This clinical case demonstrates the importance of including A. vasorum in the differential diagnosis of canine ocular diseases. Furthermore, an update of the current epidemiological distribution of A. vasorum in Italy would be of great help for local vets towards appropriate diagnostic, prevention, and treatment approaches for angiostrongylosis.