Dirofilaria repens Nematode Infection with Microfilaremia in Traveler Returning to Belgium from Senegal

Abstract

We report human infection with a Dirofilaria repens nematode likely acquired in Senegal. An adult worm was extracted from the right conjunctiva of the case-patient, and blood microfilariae were detected, which led to an initial misdiagnosis of loiasis. We also observed the complete life cycle of a D. repens nematode in this patient.

Keywords: Belgium; Dirofilaria repens; Senegal; blood; conjunctiva; eye worm; filariasis; human infection; microfilaremia; microfilariae; nematode; ocular infection; parasites; traveler; zoonoses.

Figure

Dirofilaria repens adult worm isolated from the right conjunctiva of a 76-year-old man who returned to Belgium from Senegal, and microfilaria detected by using the Knott test. A) Macroscopic image of the adult. B) Microscopic image of the adult cuticle, showing the typical longitudinal ridges. Scale bar indicates 200 μm. C) Eggs in utero, indicating that the adult is a gravid female worm. Scale bar indicates 50 μm. Panel C has been cropped and contrast was increased to improve visibility of eggs. D) Microfilaria found in the blood of the patient. In a Knott test, microfilariae usually appear stretched out and slightly longer than those observed in a Giemsa-stained blood film. Scale bar indicates 100 μm.