Dirofilaria repens
![](/Images/godic/202501/09/D_repens_LifeCycle2359.png")
![Retroocular nodule of a Dirofilaria repens worm detected in a 20-year-old woman, Rostov-na-Donu, Russia. The cyst (arrows) is shown by computed tomography scan (A) and magnetic resonance imaging (B). Ultrasonography image (C) shows a worm-like structure inside the cyst (arrow), and color Doppler imaging (D) shows marginal vascularization of the lesion).](/Images/godic/202501/09/Dirofilaria_repens_occular_cyst2359.jpg")
Dirofilaria repens is a filarial nematode that affects dogs and other carnivores such as cats, wolves, coyotes, foxes, muskrats and sea lions. It is transmitted by mosquitoes. Although humans may become infected as aberrant hosts, the worms fail to reach adulthood while residing in a human body.