A First Human Case of Ocular Dirofilariosis due to Dirofilaria repens in Northeastern France

We report the first case of ocular dirofilariasis to be diagnosed in northeast France (Alsace region), in a man who presented with a suborbital mass after a journey to Senegal. Microscopic examination of the surgical specimen identified Dirofilaria repens. 1. Introduction Dirofilariasis is a zoonosis occasionally associated with orbital floor infection. The natural definitive hosts are dogs and, more rarely, cats [1–3]. The adult female nematode usually lives in the heart or subcutaneous tissues and sheds microfilariae into the bloodstream [2–4]. The microfilariae are then transmitted by Culex, Aedes, or Anopheles mosquitoes, which are also intermediate hosts [1, 2, 4]. Humans are a dead-end host for this nematode, which can cause pulmonary, ocular, or subcutaneous lesions [2, 5–8]. Human orbital dirofilariasis is uncommon. Such patients may present with cysts resembling benign or malignant eye tumors [3, 9]. We report the first case of ocular dirofilariasis due to Dirofilaria repens to be diagnosed in Alsace, France. The patient presented with an inflammatory periorbital tumor-like lesion. 2. Case Report A 60-year-old man living in Rosheim, Alsace (northeast France) presented with a nodule on the left orbital floor on 8 July 2008. His only recent travel was to Casamance, southern Senegal, in April 2008. Physical examination showed a palpable nodular lesion of the left orbital floor, while magnetic resonance imaging showed an inflammatory nodular lesion. Inflammatory cholangioma, eyelid lymphoedema, or allergies were considered as possible diagnoses. Antibiotic and steroid therapy had no impact on his symptoms, and the nodule was surgically removed in September 2008. It measured 5？cm along its longest axis. Microscopically, it consisted of polymorphic inflammatory granuloma tissue containing plasmocytes and eosinophilic polymorphonuclear cells, with an epitheliogigantocellular granuloma surrounding a nematode cross-section (Figure 1(a)). The surgical specimen was transferred to our laboratory (Laboratoire de Parasitologie et Mycologie Médicale de Strasbourg) for precise identification of the parasite. The nematode cross-section was composed of a thick laminated cuticle with external longitudinal ridges. A polymyarian muscle fiber was visible, surrounded by a pseudocoelomic cavity. Lateral chords and male gonads were visible in some other sections (Figure 1(b)). Ocular infection by an immature male Dirofilaria repens nematode was diagnosed. The patient made a full recovery after surgery, and no further treatment was required. Figure 1: (a) Inflammatory