[Difficulties in diagnosis of human dirofilariasis outside known enzootic areas]

Human non-visceral dirofilariasis, a mosquito-borne disease of carnivores (dogs), is chiefly due to Dirofilaria repens in France and is well known in the Mediterranean basin. This zoonosis can be misdiagnosed in northern areas of France. We present and discuss two human cases diagnosed in Abbeville and Amiens (Picardy) by histological examination.

The former case appeared as an axillary tumefaction occurring in a 41-year-old women 6 months after holidays in Montauban (southwestern France), the other as an intraorbital 'tumor' in a 53-year-old man who travelled for professional purposes in Central Europe and North America. Morphological, clinical, and epidemiological data of these human infections are discussed and the diagnostic features in tissue sections for species identification are reviewed.

Increasing travel customs during the last decades favour the emergence of zoonotic parasites unusually in human hosts. Outside known enzootic areas, diagnosis is often delayed until pathological examination. In France, the incidence of human dirofilariasis has steadily increased and must be considered in the workup of cutaneous or intraorbital nodules.